Changing the ECTS (Engine Coolant Temp Sensor)

[wolfman]

The ECTS is a two wire sensor used by the PCM to measure engine temperature and set engine/transaxle operating parameters accordingly. On 91'-95' SOHC and DOHC engine equiped "S" series Saturns, there is a SEPERATE sensor used for the gauge. On these cars, the ECTS is the TWO WIRE sensor located just below where the upper radiator hose attaches to the engine. (The other ONE WIRE sensor nearby is used for the gauge) On 96'-02' SOHC and DOHC engine equiped "S" series Saturns, the ECTS is in the same location, but also operates the temperature gauge. (The other one wire sensor is deleted)

To change the ECTS in either case you'll need:

13mm DEEP WELL socket (6 point variety recomended)
and a socket wrench.
Perhaps a pair of needle nose pliers

Obtain the "NEW style" all brass ECTS from SATURN, it will come ready to install with nothing else needed.

DO THIS ONLY ON A COLD ENGINE!

Proceed as follows:

Remove the air snorkle running from the front of the car to the throttle body. (Or air filter housing on 91'-94' SOHC)

Locate the ECTS as described above, the electrical connector is held on by a plastic connector with two little "ears" on it that grip the lip of the ECTS. It can be hard to see. To remove the connector, SQUEEZE the plastic hood about 3/8 in. BELOW WHERE THE WIRES GO IN with either your fingers or needle nose pliers and GENTLY pull away from the engine. DO NOT PULL ON THE WIRES! If the connector does not easily release, reposition your fingers (or the pliers) and squeeze/pull again. Eventually you will find that "magic spot" and the connector will come off quite easily.

Inspect the inner portion of the connector for any signs of corrosion. If corroded, it should be REPLACED (Available from Saturn) but cleaning it can sometimes do the trick.

Remove the coolant resevoir tank cap to relieve any pressure in the system, then put it back on TIGHTLY to avoid excess coolant loss when the sensor is removed.

HAVE THE NEW SENSOR READILY AVAILABLE BEFORE THIS STEP!
Using your 13mm deep well socket, remove the old ECTS from the engine by turning it counter clockwise. Keep the socket as straight as possible over the sensor. (When it comes free from the block, some coolant will spill out, DON'T PANIC)

Quickly thread the new ECTS into the hole BY HAND to minimise coolant loss and prevent crossthreading.

Using the 13mm deep well socket, tighten the new ECTS into the engine by turning it clockwise. Keep the socket as straight as possible over the sensor to avoid damaging it. Keep turning until you feel it "bottom" in the hole but DO NOT OVERTIGHTEN IT!

You reconnect the electrical connector by placing it over the end of the new sensor and then GENTLY pushing in on it while SLOWLY rotating the connector. When everything lines up, it will then just pop into place.

Reinstall the air snorkle.


NOTES:
Coolant loss will be minimal but messy. You should NOT need to top up the coolant as less than an once or so will leak out. You "can" rinse off or mop up the spilled coolant if you wish (recommended) Keep PETS AWAY some (green) antifreeze is POISONOUS to them but tastes "sweet".

You "should" reset the PCM after changing this (or ANY sensor) this does NOT require any special tools, just disconnect the NEG battery cable for about 15 secs.

When remeoving the electrical connection from the sensor, TRY using your fingers FIRST (a little contortionary talent helps) use pliers as a "last choice"

DO THIS ONLY ON A COLD ENGINE!

[Luke]

Fm Wolf
DO THIS ONLY ON A COLD ENGINE!
The best way to insure this is to start the project the following morning.

[Shawn]

Very helpful, thank you Wolfman! One question: How much should I expect to pay for the new ECTS?

[wolfman]

$12-$15

[amazinghl]

~$20 when I bought mine from saturn.

[DualCamCoupe]

So the ECTS's threads don't need any anti-seize?

[wolfman]

You should not have to change this again, and if purchased from Saturn, the new ECTS threads will already have a sealant applied to them right out of the box...so as posted it's ready to install.

[Lurker1999]

If your local dealership is charging ridiculous prices you can order the ECTS from www.saturnparts.net which will get you a sensor shipped from Saturn of Colma, California for $11.27 plus roughly $5-6 UPS ground shipping.

[cris_thomas]

Let me reiterate what Wolfman said

DO THIS ON A COLD ENGINE

I did this yesterday and let thew engine cool down for about an hour and half or so. It was still warm to the touch. Warm does not equal cold. I pulled the ECTS and had a rag ready to catch the few onces of coolant I knew where going to spill out. Well about three quarts later it finally stopped spewing. I got coolant all over everything!

Also, like Wolfamn said, be careful removing the electrical connector. I ended up braking the old ECTS in half. Which freaked me out as I almost thought I wasn't going to be able to get it out.

Anyway, after I replaced the missing coolant I noticed that the new ECTS made a huge difference on the idle smoothesness of the car.

[Luke]

FM Luke

The best way to insure this is to start the project the following morning.......

[Craig]

My son and I (mostly him, I just oversaw it) did one on his '94 SL2 this afternoon since it always started hard and ran rough when cold. The old one had a big crack in it, yikes! Put the new one in and it started right up and idled like it should. Didn't reset the PCM because we ran out of time, but will do that tomorrow.

[JohnS_98]

I just happened to stumble across this thread.
When I looked under the hood, sure enough mine was leaking. It was leaking so slow that it didn't leave any drips on the driveway. There was only dried "crusty" coolant around the sensor.
I paid about $12 from Saturn of Rochester for the sensor. It is good to go now!

[dcamden]

To you other shadetree mechanics make sure you follow Wolfmans advice and use a 13mm 6 point socket. I had the cooling system drained as I was changing the thermostat also. I tried to remove the sensor with a 1/2" 6 point (the same right?)WRONG! Most times the 1/2" and 13mm interchange but not here. Had to wait for the wife to come home so I could make a trip to Sears for the right socket. Don

[2NDSOUT]

Well, yesterday was a fun day...

I had bought my ECTS to replace on my wife's 92 SL1 and finally had the day to do it, with no rain or anything. I had been telling my wife about replacing the ECTS for about a month, and yesterday was the day. I had downloaded Wolfman's procedure, which was helpful...except for when I got to taking the old ECTS out and putting the new one in....

I took my wife to work, so her car was sitting with a cold engine for 24 hours. She didn't drive it at all Saturday night going into Sunday, so I could replace the ECTS. I went and bought a deep well 13 MM socket for socket wrench and went to work...

When I got back and started in on her car, and took the old ECTS out (which was ALSO a Brass ECTS...but the car ran hot...explain that one!!) Her entire contents of Antifreeze leaked out all over the engine...I was just anticipating a few slow leaks...not a gushing stream of antifreeze!!!! Her entire coolant tank had to be refilled (luckily I had bought a container of Prestone earlier that morning). Her coolant was a beautiful bright green...so I know that there are no leaks or contaminations. Now my question is, why would the entire content of antifreeze leak out and not just a little, I know that it obviously flows through the engine block, but why would this happen even on a completely cold engine?? I did EVERYTHING per wolfman's post.

Anyone have an idea?

The car runs better now and idles around 1000 RPMS and runs cooler, the fan kicks on to cool the engine down when the needle hits right at about the 3/4 mark past the half way point.

[David 93 SL2m]

I recommend changing this sensor at the same time the coolant/antifreeze is changed. First drain the coolant/antifreeze from the cold engine (radiator and engine block). Unscrewing the cap on the overflow reservoir will relieve pressure and allow most of the coolant/antifreeze to drain. Then swap the temperature sensors. Some coolant/antifreeze might still come out so have some rags handy - but it shouldn't be pints and pints that flow out after removing the old sensor.

[bigbird]

Originally posted by 2NDSOUT
Now my question is, why would the entire content of antifreeze leak out and not just a little, I know that it obviously flows through the engine block, but why would this happen even on a completely cold engine??

If you took off the overflow tank cap, air can enter the system and the coolant will gush out. If you had left the cap on tight, then coolant would only dribble out of the ECTS threaded hole in the block.

[ZoomEquipd]

Originally posted by bigbird
If you took off the overflow tank cap, air can enter the system and the coolant will gush out. If you had left the cap on tight, then coolant would only dribble out of the ECTS threaded hole in the block.

I can attest to that, did mine the other day, didn't take off the overflow tank cap, nice gush of anti-freeze all over the engine. Then i remembered that i had forgotten to do that. A lesson learned i guess. Taking off the cap will allow the pressure to equal out.

Do you just wash the engine off w/ some water from a hose to get it clean? My dad said to take it to the car wash and use the pressure washer on it.. i'm worried that the pressure would cause damage??

[bigbird]

Originally posted by ZoomEquipd


Do you just wash the engine off w/ some water from a hose to get it clean? My dad said to take it to the car wash and use the pressure washer on it.. i'm worried that the pressure would cause damage??

I agree with you. The less pressure the better. Just use a garden hose and rinse off all the antifreeze.

[DrPimper]

Here is a trick I am supprised to not have found on any saturn form i have visited and every saturn page I have visited has advice on installing the ECTS (all of us saturn owners know is a common problem with out beloved saturns)

Follow Wolfman's instructions with the Driver Side of the Car Jacked up so the Coolant does not flow out at you while you are changing the ECTS. I take full credit for this ECTS Installion tip and I thought of it before the second time I had to change the ECTS on a sautrn.

[Spazie]

I'll try your suggestion when I change mine, DrPimper. Thanks! I'll report my findings here. I should be doing it next weekend.

[2NDSOUT]

Hey Spazie,

Be careful when you go for the wire connector...there is a plastic piece that covers the wires which is attached to the sensor piece. I pulled it off and thought I had broke the plastic cover, but it snaps right back on.

[freakerz]

I bought meters, you know for oil, temp and volt.. you say "DO NOT PANIC", well I PANIC and I returned the product to Canadian Tire LOLOLOL.. I didn't read your post in time I guess =( .. oh well, 40$ for something else.. like paint..

[wolfman]

Just read this after a few weeks. Important note: Put the cap BACK ON the resevoir tank TIGHTLY after removing it to relieve any pressure on a STONE COLD engine. The cap is a ONE WAY VALVE. If you still get a huge amount of coolant loss out the tiny ECTS port when the sensor is removed, either:

1. The engine was indeed NOT stone cold, or:
2. The resevoir tank cap seal or cap one way vent valve in it is bad.

You should not get a huge amount of coolant loss if the directions are followed to the letter and the system is intact (sealed) and the cap is good and securely tightened, after being initially removed to vent any residual pressure.

[cozkramer]

I'd just like to say Hi to everyone.. The house has a '96 SC2 that I get to work on for some reason. I mainly deal in old pre '72 cars so this aluminum and plastic thing is new.. Bear with me plz.. :) I've read over this forum for a few days and will say, WOW! What a great buncha guys!

So, onto the reply.. I cannot stress enough Wolfman's "Don't Overtighten" statement.. There's a photo to follow.. I'd like to add, Do NOT use a 1/2" Socket Wrench to install this! Stick with a 3/8 or 1/4. It may have only cost me an extra $17 for another part, but the time and agravation, not to mention scare factor was not worth it!

The black twisty thing is a #4 Fluted Screw Extractor.
http://cozkramer.servebeer.com/saturn/broken.jpg

[sierrap615]

Originally posted by ZoomEquipd
Do you just wash the engine off w/ some water from a hose to get it clean? My dad said to take it to the car wash and use the pressure washer on it.. i'm worried that the pressure would cause damage??

don't use a pressure washer, that would be very bad. on his old cars from the 60s or 70s, this may have worked. but on today's cars the damage would two fold. first there are countless sensors and modules and solinoids and blahblahblah, much more then any older car. second, and more importently, all the wiring connection have weather seals, which work great normally. but with a lot of pressure, not only will the weather seals fail, when the pressure returns to normal, water becomes trapped inside the seals and connectiors, and its not that it may corrode, its that it WILL corrode.

[Luke]

Fm Sierrap
second, and more importently, all the wiring connection have weather seals, which work great normally. but with a lot of pressure, not only will the weather seals fail, when the pressure returns to normal, water becomes trapped inside the seals and connectiors, and its not that it may corrode, its that it WILL corrode.

Point, very, very well made...

[JayNYC]

Wolfman, you are amazing! I changed this part a few eeks ago and my gas mileage has gone from 175 miles per tank to 310!!! This part paid for itself in under a week!


Thanks!

-Jason

[sps SOHC]

Originally posted by JayNYC
Wolfman, you are amazing! I changed this part a few eeks ago and my gas mileage has gone from 175 miles per tank to 310!!! This part paid for itself in under a week!


I'm not getting too great gas mileage. I'm replacing my radiator so I'm going to replace this too. Right now I think I'm getting around 240-260 miles a tank. I don't really know because my odometer is broken. :ugh:

[sierrap615]

Originally posted by sps SOHC
I'm not getting too great gas mileage. I'm replacing my radiator so I'm going to replace this too. Right now I think I'm getting around 240-260 miles a tank. I don't really know because my odometer is broken. :ugh:

you may want to throw in another $10 and change the thermostat too.

[freedominco]

followed these instructions and it took ten minutes

[Kentai]

Should I have to change my ECTS on my '01 SL1 after 25k miles (I part-time deliver pizza in it, miles rack up fast)? Would it make a difference in my mpg? Any improvement would be fantastic considering the current gas prices...

[amazinghl]

Would help if you tell us what you're getting now.

[Kentai]

Pretty consistent around 240 on a full tank that I run nearly down to E. :) What I was curious about is whether or not this new all-brass sensor comes stock on my car already or not, since it's a '01? And don't tell me to go look, that would require... uh... effort.

[freakerz]

Saturn 93 SL1 ECTS: 13mm DEEP WELL :D

http://www.saturnfans.com/photos/data/500/7096ects1.jpg

[geeminator]

I guess this is another good thing to replace after I replaced my valve cover gasket and spark plugs/wires the other day...The car has stumbling idle after it warms up unless it's the computer "relearning"...Or is there some other issue I need to address?...no codes being thrown and spark plug gap is at .040 Car is a 97SL2.

[zippy_LiL_sL1]

Yup, just looked at the old ects about ten minutes ago. It was cracked all the way around. 10 minute successfull swap out.. following wolfman's instructions. I am noticing a considerably cooler running engine. Maybe gas mileage will improve as well?

[sps SOHC]

my engine temp never goes above quarter now w/ the new ECTS and the radiator. I would think that it should...

[Razorbak]

Originally posted by wolfman

Using the 13mm deep well socket, tighten the new ECTS into the engine by turning it clockwise. Keep the socket as straight as possible over the sensor to avoid damaging it. Keep turning until you feel it "bottom" in the hole but DO NOT OVERTIGHTEN IT!

FYI, the torque spec is 8 Nm (71 in-lbs).

[canaryrx8]

can someone post a pic of the location for a 2000 sl2? either my search criteria was off or ...? but I could not locate one. Thanks!

[Razorbak]

The forum search database isn't working very well right now. (Forum owner is testing out new features.) Check the pictures in the following thread, and then look under your car's hood in the same location as the lower sensor that the wrench is turning...

http://www.saturnfans.com/forums/showthread.php3?s=&threadid=37884

[canaryrx8]

sweeet. Thanks!!

[joyrider]

Wolfman, you are awesome. It would have taken me forever just to find the right socket.
BTW, I think removing the battery (I have a 95) is a good idea--there was no way my short fingers could reach the plastic connector. With the battery out of the way I had no trouble.
The only sad news is I discovered that the damn thing had already been replaced :hothead: so I did not solve my problem (d'oh!!)

[HomeComing99]

Wolfman - you ARE awesome. Just did mine on a cold engine. I would say I lost maybe 1/2 cup of coolant. I wedged a towel under the hole and it soaked all the coolant right up! No mess.

I forgot to unkook the battery for 15 seconds. Will I still be ok?

Tomorrow I am having my thermostat replaced. Hoping the car will run like new after these two cheap and easy fixes.

[sierrap615]

I forgot to unkook the battery for 15 seconds. Will I still be ok?


most likey yes, but do not expect any miracles right away, the PCM will adapt in time(at least a few hundard miles). dissconnecting the battery(or as i perfer, pulling the PCM B fuse) will erase the PCM's keep alive memory(KAM or RAM) and make things a lot faster(rarely more then 5 miles)

[HomeComing99]

Sierra,

I just moved from Lisle, IL up to the cold north last year! We would have been nieghbors!

I can certainly find the fuse and pull it. I didnt figure pulling a fuse would do much. Is that in my regular fuse box? Do I have to do anything special?

Thanks!

[Luke]

Fm >> HomeComing <<

> Is that in my regular fuse box? <

Yes, you should find it in the fuse box, which is located in front of the battery. In taking the top of the fuse box off, just look on the inside top to see where the actual fuse is located. The inside Top has a full outline of every fuse and their respective locations.

[HomeComing99]

Replaced the sensor last night. Pulled the fuse this morning.

OH MY GOD - This is a new car. It idles about 1000% better, runs better and the trans is as smooth as silk. Not bad for a car with 87k miles!

Thanks for all your help!!!

[Razorbak]

FYI, to no one in particular... if you're attempting to determine if your ECT sensor is faulty, and you want to test this theory before buying/ordering a new part, you can temporarily swap out the Intake Air Temperature (IAT) sensor on the inlet to the air filter box and put that in the ECT sensor's place to see if that resolves the problem. The IAT sensor is the same as the old resin-style ECT sensor, but it's probably not cracked because it's surrounded by air rather than hot water and antifreeze.

[flapjabby]

Jacked up driver's side as suggested and lost very little fluid.

One note, on my '94 SOHC, the two wire sensor isn't actually right under where the radiator hose is connect to engine, that's the sensor for the gauge, the ECTS for the fan (the two wire sensor that this thread is about) is actually down and under a few inches away from the one wire sensor. I first mistakenly replaced the one wire (green) sensor which has a slightly different connector than the two wire.

ECTS Part # 21025106 ($17 in Phoenix,AZ).

I also pulled the PCM B fuse and replaced it to reset.

How long after I replace the ECTS should I expect to see results? Immediately after replacing, the engine still revs up to 3k rpm on start, then drops to 2.5k-2k rpm while in neutral/park. In gear it's around 1k rpm.

[green]

My 95 SW runs 2500 rpm after starting up. After taking it totranny shop, the mechanic disconnected the engine coolant temperature sensor #12117087. It's a two wire connector with white coating with two butt connectors. What wires does it connect to (where are they located color, green or black?) Thanks.

[green]

Dear Wolfman:

I've got a new engine coolant temperature sensor part #12117087 from Saturn. The temperature gauge is not working and the dealer didn't give me a diagram or instructions. The mechanics at tranny shop disconnected the sensor 95 SW1 and it's missing. The new part has white coating and two butt connectors. I don't know where it goes to. I only see one wire being loose close to the connector and under the air housing. Please help.

[Razorbak]

That part number you keep referencing is the replacement CONNECTOR, not the sensor itself. It needs to be hooked up to the single wire from the engine harness that feeds the dash temperature gauge. I don't know offhand what color the wire is, since my FSM only covers the 1996 model year, which only uses one dual-wire sensor, but if you have a loose single wire in that area, I would venture to guess that's probably it.

[green]

After getting my 95 Saturn from tranny shop the horn didn't work neither temp gauge. After putting a connector temp gauge works but engine light remains on. Is something wrong with the wiring so the engine light remains on and the horn does not work?

[flapjabby]

I replaced ECTS, reset PCM-B, and have driven over 150miles, yet my engine on '94 SOHC still idles around 2500 rpm in park/neutral. Temp gauge reads ok, about in the middle.

Do I need to have more patience and let the car go more miles before I see results or is there another issue I should look into getting fixed?

thanks in advance!

[denclar]

Called my friendly local Saturn dealer to get a price on an ECTS and the Parts Dept. quoted me $20 but said they recommend also replacing the contact thing that connects to the ECTS--another $30.

From what I'm reading here, that sounds like a rip off.

Anyone have an opinion?

Also I called the Service Dept. and they quoted me a price of $160 to replace ECTS and contact. $110 labor?

I'm really losing faith in this dealership.

Two questions--

First--is it a good idea to replace the contact as well as the ECTS?

Second--my SES light isn't on, but my 97 SC2 (5 speed) idles at about 1000, I'm getting about 24-25 mpg, and my temp gauge never goes above 1/4 even in the hottest Florida weather. Could I have a bad ECTS but no light?

Thanks

[Luke]

Fm >> denclar <<

> First -- is it a good idea to replace the contact as well as the ECTS? <
If the "contact" is not damaged, then I would simply replace the ECTS
>> Second -- my SES light isn't on, but my 97 SC2 (5 speed) idles at about 1000, I'm getting about 24-25 mpg, and my temp gauge never goes above 1/4 even in the hottest Florida weather. Could I have a bad ECTS but no light?<<
Big time -- Yes, you could have a bad ECTS, with no fault being sent to the computer, thus no Check Engine Light.

[David 93 SL2m]

I'm getting about 24-25 mpg, and my temp gauge never goes above 1/4 even in the hottest Florida weather. Could I have a bad ECTS but no light?The temperature gauge reading indicates that most likely the thermostat is broken - stuck in the "open" position.

If the PCM sees the engine is not up to normal operating temperatures (via the coolant temperature sensor) then it will adjust the fuel/air ratio so that the engine will consume more gasoline in an effort to bring the engine up to normal operating temperatures more quickly. But if the engine never reaches normal operating temperatures, then it will continue to keep that ratio of fuel to air on the "rich" side - and fuel economy will suffer. Based on this and the symptons described I'd guess the thermostat needs to be replaced.

Since we need to drain the coolant in order to replace the thermostat, it would not hurt to replace the coolant temperature sensor at the same time. Since the temperature gauge on the dashboard is working and since the fuel economy is suffering, I'd guess the coolant temperature sensor is most likely okay. The coolant temperature sensor is $14 plus or minus $5. But for less than $20 and with the coolant drained I'd probably just replace it as cheap insurance.

By the same token, this is also a decent time to think about replacing the upper and lower radiator hoses...

Tip for draining the coolant from the S-Series: there is a drain valve at the bottom of the radiator on the passenger side and there is a 10 mm drain bolt for the engine block located near the underside of the thermostat.

[Razorbak]

If the "contact" is not damaged, then I would simply replace the ECTS

I think it's rare for the connector to be damaged, unless someone tried to force it on the sensor in the wrong orientation. A more likely problem is corrosion inside the connector that should be obvious even to an untrained eye. If in doubt, just reach down beneath the head, disconnect the connector, and examine it. If it's not corroded, it's probably fine and doesn't need to be replaced. Then you can save some money. Just check it yourself for free. :yes:

FWIW, I would change the ECT sensor before replacing the thermostat. You don't have to drain the coolant to replace the sensor. You will to replace the 'stat. Start with the easy stuff first and then see if that corrects your apparently "low" dash temperature gauge readings.

[denclar]

My thinking is that since on my model the ECTS sends information to both the temp gauge and the computer, the water temp may be OK but the sensor is sending low readings to both the gauge and the computer.

[Razorbak]

My thinking is that since on my model the ECTS sends information to both the temp gauge and the computer, the water temp may be OK but the sensor is sending low readings to both the gauge and the computer.

My thoughts exactly.

[mgrace74]

I was having this same problem last week with the two lights flashing on and off. Today my car overheated and when I checked the coolant, it was full of what looks like mud. My heater also stopped working today. Does anyone know if this could be related to the ECTS?

TIA.

Mike

[blimey]

So, I went to the dealer to get a new ECTS for my '95 SL1. Based on what I read here, I wanted to be sure to get the all-brass part. The parts guy hands me a part that looks a lot like this one; {photo robbed from another post here}

http://207.115.56.29/webdn95v403/saturn/pic02.jpg

The above part has a hollow plastic/resin top, and doesn't look anything like I expected it to look like. I expected it to look like this part shown in the how-to w/pics thread;

http://207.115.56.29/webdn95v403/saturn/pic03.jpg

Does anyone know the exact part# for the ETCS for a '95 SL1? Did the part # change when the part went all-brass? How does Saturn differentiate between the ETCS and the sensor used for the gauge? {is there a more specific name for the sensor used for the gauge?} Not to mention the air intake temp sensor, is that the same part# as the ETCS, and has it gone all-brass too?

So did the parts guy try to give me the wrong part? I think he gave me the gauge sensor, even though I asked for the ETCS. Any part #'s or other help appreciated.

[David 93 SL2m]

Saturn part number 21025106 is the brass coolant temperature sensor for all 1991 to 2002 Saturn S-Series cars. This is used in the lower port of all 1991 to 2002 cylinder heads. This sends information to the PCM (computer) for things like adjusting the gasoline and air ratio, helping decide whether to turn or off the radiator fan, etc. This is not only the temperature sensor for the coolant but also the same part that is used for sensing the air temperature and for sensing the transmission temperature. This has a connector for a double wire harness.

Saturn part number 21020124 is the coolant temperature sensor for 1991 to 1995 only Saturn S-Series cars. This is used in the upper port of 1991 to 1995 cylinder heads. This sends information to the temperature gauge on the dashboard. This has a connector for a single wire harness.

If the two sensors get mixed up then the best way to identify them is by the connector for the wire harness. One wire harness has one wire and the other wire harness has two wires; the connectors are different and these parts cannot be accidentally swapped.

The next time I buy one of each I will photograph them and post them here...

[blimey]

Thanks David!

[meribona]

Followed Wolfman's instructions this afternoon and was able to switch out the ECTS on my 98 SL2 with no problems.

Some observations that may be helpful to others:

1) The ECTS I took out was indeed the old resin-tipped version. Odd thing was, however, that the tip wasn't cracked --- even after 68,650 miles.

2) It took me a few minutes to find out where the ECTS actually was. The diagram in the Chilton's manual is too small to be helpful, but I did eventually find it. Look below the air intake, slightly inboard (i.e. going toward the passenger side) of the battery and you should see two wires out in the open that aren't encased in a sheath or black plastic conduit. Follow the wires to the engine block and you'll find the ECTS. Removing the battery will make accessing the ECTS easier.

3) Be sure to have rags and buckets handy because it seems like you'll spill at least a 1/2 cup of collant regardless. I jacked up the driver side of my car in the front and back by about 4 inches or so to minimize coolant spillage. I still got spillage however so I ended up draining about a gallon of collant from the radiator stopcock drain near the passenger side front tire. Removing the cap on the surge tank helps the draining process immensely.

4) I've only driven 3 miles on my new brass-tipped ECTS but I appear to reach operating temperature (~25% on the temp gauge) much sooner now. On the old ECTS, the temp gauge needle would be stuck at zero for several minutes after startup. As far as idle goes, the engine seems marginally louder than it used to. The big difference, however, is that the idle sound is now constant whereas on the old ECTS it would change volume depending on speed, engine temperature, etc.

[dp97sc2]

I just changed mine today....
time to complete about 1/2 hour.
.
.
.
price for part =$25 with tax ouch!
.
.
.
knowing my idle, temp and fuel econ is right again...priceless!
.
.
fuel econ before change=only 18mpg!
fuel econ after ??? (probably 33-37mpg based on past)

next on the list is prolly replace the control arms. Im figuring this could easily be a 1/2 day job.
p.s. the old one I pulled out was the resin type, 225K miles and it WAS cracked.

[rlalonde]

I changed my ECTS this past weekend. Made a world of difference. I was getting intermittent problems that I could not nail down. Found out that one of the pins on the coolant sensor was broke off and just connecting when "it wanted to". Anyway, once again, thanks to Wolfman the problem is fixed!!!!

[allogene]

I have a 96 SL1 and my Coolant temp light just started flashing the other day. I checked the coolant reservior (which was low) and added coolant. It has been about 48 hours and the light is still flashing.

My idle level is sub 1000 at idle (usually about 800) and I still get 300+ miles per tank. The car has ~83K miles. I am curious if the ECTS could cause the light to flash? Could it be something else?

I checked the coolant today I had to add more coolant. There is no puddle or signs of leakage. I was thinking that the coolant was just low and once the system was pressurized the level readjusted?

Any help would be appreciated. I really do not want to take the car to the dealership.

[Daryl92sc2]

I was able to find the new style brass sensor at NAPA P/N TS5587 for the low price of $8.99 + tax.

[Daryl92sc2]

Changed ECTS with new brass sensor, it doesn't pull the 15 code (or any other), but it still just runs until it gets warmed up, then dies again.
Any other sugestions?

[robotpm]

By following these instructions I was done in under 10 min.

Thanks wolfman with your info it was a breeze.

[PimpcessYellie]

PLEASE HELP ME!!!!!.... im a girl that doesnt know all that much about my 97 sc1 with 87kmiles... my problem is that my temp usually stays around or between the 1/4 and 1/2 marks but once it reaches the 1/2 or raises to between 1/2 and 3/4 (NOW CAUSE OF THE SUMMER) my coolent resevoir overflows from the cap between a mix of liquid anitfreeze and steam...at a red light or in a parking lot is the only time u'll notice this...just today my boyfriend and i changed ...well didnt really change...there was no thermostat on my car...probably from the old owner...so we put one on...180degree...so we drove it around and even with the new thermostat the resevoir still steamed and overflowed WITH a thermostate on it...i also got my waterpump changed within the last yr / 20,000 miles....o...another rpoblem...last summer i was getting 300miles to a full tank and now im getting 200...wats up with that...ive been reading about these ects and my boyfriend and i are gonna replace it tomorrow...any other suggestions or people with this problem??? please contact me ASAP! :eek:

[hosstics]

I just changed the ECTS today on my 93 SL2. Just for the record, I currently have 227,000 miles on this car and the ECTS has never been changed. I changed it due to research on this site, which has been extremely helpful. My check engine light would go on randomly and my coolant temperature light would flash even more often. Also, I would experience rough idle when in Drive and stopped at a traffic light or stop sign. It feels as though the car is going to stall and I need to give it some gas. Funny thing is, this doesn't happen all the time and I haven't been able to notice a pattern. I bought the replacement ECTS at Auto Zone (part# TU227) and it is of the brass type. The old ECTS was actually in pretty decent condition, although I have never seen a used one before to compare it against. I had no problem replacing it, aside from some difficulty resetting the connector, by following instructions on this site and the Chilton's manual, but things were not so good after I started the car once done. The fan kicked on immediately after starting the engine and stayed on and the coolant light on the dash and the check engine light both illuminated and did not go out. I did have the negative battery cable disconnected while replacing the ECTS. Although I did not let the car run more than a few minutes and did not drive it, what happened? What did I do wrong? Could the new ECTS be defective? Is the connector bad? Any advice would be greatly appreciated...

[sierrap615]

one of two things are possible, if the SES light is flashing chances are you are somehow in diagnostic mode, which is normal acceived by jumpering the A and B termials of the ALDL. but more likely - if the SES light is steady then there is a problem with the sensor or the wiring. check the pins on the sensor to make sure they haven't folded over and are shorting out or have broken off, and make sure ether your or the part guy at autozone haven't confused the one-wire sender and the two-wire sensor - use this for reference - http://www.saturnfans.com/photos/showphoto.php/photo/19837/

[hosstics]

Thanks for the information sierrap615. I had already removed the Autozone ECTS, returned it, and reinstalled the original part. I plan on stopping by my local Saturn dealer and purchasing the OEM ECTS and if they have it, the connector. Hopefully, this will resolve the issue I have been having. Any other suggestions on why my car feels as though it is going to stall? I was also thinking it might be the fuel filter, but not sure if I can perform this one myself.

[Norseman]

I just changed my out on a 1996 SC2. The most difficult part of the procedure was removing the wire connector. You have to contort your hands to get in there. I was trying to find "ears" to squeeze on the white portion where the the wires entered. I kept trying to feel around with my fingers feeling for tabs of some sort. After looking at the new sensor, I tried feeling around the black portion of the connector and was not sure what I felt. After awhile of just squeezing around the black portion it finally came off.

I removed and recapped the coolant overflow container and jacked up the driver front. I put some paper towels underneath the area and only a small amount of coolant dripped out. After replacing the sensor, I disconnected the negative battery cable for 20 seconds.

The first thing I noticed after starting the engine was how much smoother it was. I drove it for about 5 miles. When I come to a complete stop and idling, the engine is smoother. The interior panels don't rattle as loud as before...lol

:yes:

[96sl2]

Wolfman thank you so much for posting these directions I did this to my 96sl2 and wow what a difference up into this point I had no idea what the heck was going on with my car then I stumbled across this and you guys described all the symtoms my car had so I used your guide to replace the ECTS and its like I bought a new car. :) :) :) :) :) :) :)

[David 93 SL2m]

...and its like I bought a new car.Next try replacing your upper motor mount, also known as the torque axis mount. It is less than $100 (even if you optionally buy 3 new bolts and 5 new nuts), it can be done in your garage in less than 10 minutes, and the result is most vibration from the engine is eliminated. Over time this component weakens and most people say their car feels like it is brand new after replacing it.

[96sl2]

Thanks for the info David 93 I will replace upper motor mount and post my results thanks again. :) :) :) :)

[andyr13]

The top sensor is the ECTS correct? I just want to make sure I don't buy the wrong one. The lower one is the sensor that controls the temp guage right? Should I replace both or just the ECTS and see if that helps first?
http://www.saturnfans.com/photos/data/650/thumbs/ECTS2.jpg (http://www.saturnfans.com/photos/data/650/ECTS2.jpg)

[PurdueGuy]

Replaced my ECTS today - went very smoothly using these directions, and only about a soda capful of coolant came out (did the jacking up the driver's side, and removed & put back on the tank cap). Car seems to be running about the same, which is very well, fortunately. The engine temp still doesn't go more than a hair above 1/4, though. Will be considering replacing the thermostat next, unless gas milage improves enough to make me not bother with it. :)

[bgates2b]

Just curious.

I replaced my ECTS this past weekend. I noticed that the bag in the pictures shows a Saturn bag; mine was in a GM bag. Is this the correct sensor? Do multiple GM engines use the same sensor?

I am concerned because even though the engine is much smoother and quieter, I did not notice a noticable improvement in MPG. At least, not according to my gas gauge.

[EPYNGNDM]

Thanks for this, bought part and socket from Kragen. Did whole job in 30 mins with minimal coolant loss. Also cleaned connector with Q-tip to get off gunk.
Comes on now at 3/4 temperature and pulls down quickly to below half.

Thanks again, Wolfman !

[tenn734]

a big thanks to wolfman and auxmike for the instructions... much much better than any chilton or haynes manual


everything went relatively smoothly
too bad the whole job cost me $150... i went to get a 13 mm deep socket and ended up buying the a whole 100 piece mechanics set.

anyone want to buy a slightly used authentic, genuine saturn ECTS?? ill start the bidding at $25.
j/k

the old resin one has a hairline crack...i feel a lot better now witht he new brass one ...Thanks again!!

[mjo]

Just thought I might add my two cents worth. The ECTS has a 1/8" NPT pipe thread. When you tighten the ECTS, unlike a bolt, it will tighten slowly. It is easy to overtighten and some on our site have stripped their sensor because of this.

[chinch33]

Thanks for all the tips on this everyone. I changed my sensor in no time, and only 1 small drop of coolant came out! depressureized the coolant tank and jacked up driver side of car as suggested. worked great! made a huge difference in how the car runs!

[carbaugh]

I just changed the 2 sensors in my 94 SC2 (DOHC). Mine must be a weird one because it has 2 sensors, but both are TWO WIRE. I haven't noticed much improvement in the temperature reading / fan behavior. Could I have mixed up the sensors? The bottom one has a gray colored tip and is slightly longer. The top one has a ligher colored connector tip. Since these are both 2 wire, what should the colors of the wires be?

I should mention that this car has a new radiator, hoses, thermostat, and water pump, all replaced before I bought the car. The engine doesn't exhibit any tangible signs of real overheating, just the darned gauge.

Fuel mileage is mediocre, around 28mpg.

Any help appreciated!

[williammcginn]

I was lost and now am found. Changed the ECTS as per the Wolfman and the car runs great not bad for $21.02 for the sensor at the dealer, its brass thanks.
Bill
"No one looks good with brown lipstick" Frank Zappa

[Ghostrider359]

I had a feeling my old ECTS was blown...and I was correct...very correct. The tip was melted and cracked...and the connector pins were mangled! I got a new one from the dealership for about $18 plus tax.

I didnt come here to see how to do this...which was my first big mistake. I pull the old one out with the wrong deep well socket...it felt like it was contacting the nut properly...but when I began to turn the rachet more and more, I could hear something leaking...and leaking and leaking and leaking. The engine was not stone cold, but I had left it out in the cold evening for about 2 hours or so. Anyway, the first gen Saturn Haynes manual (from when we had our 'ol '94 SL2) said that all you have to do is undo the resevoir cap to release any pressure (obviously you wait till the motor is cool) and then undo the electrical connector and then unscrew the sensor. Nothing about coolant leaking...though I expected some...but I think a lot more than that came out.

I had a rag under the sensor bung to contain any leakage and it was thoroughly soaked...plus there was a good puddle under the car. Anyway...I found that I couldnt retighten the old sensor...as it was jammed into the socket...so I do my best to contain more fluid and take the socket and get a hammer (the sensor was busted anyway) and got it out...then I quickly screwed in the new sensor by hand and then torqued it down with the proper socket. Probably not the right order of things...but I was panicking.

Anyway...I checked the resevoir...and of course its empty. So I go inside and fill up a pitcher of distilled drinking water and begin filling it back up to the "full-cold" line. I make sure everything is back in place and take it out for a spin...and to be truthful...I raced someone...mainly because they were being a ******* by nearly kissing my arse for almost a mile. So when the guy in front of me got into a turn lane...I floored it to get away...and away I got...it was a second gen Neon...and by the lack of power...probably an ATX...which I dont knock, cause I had a first gen Neon ATX and loved it...but second gens are much much heavier.

Anyway...the whole time the temp needle was just a hair over the 1/4 mark and never changed. I get home from my little test and do a quick check...noticed no leaks...nothing out of the ordinary...lock 'er up and go inside. I come out later to run an errand and drive for about 5 minutes and am welcomed with the low-coolant symbols flashing...I pull over immediately and pop the hood. Again...nothing out of the ordinary...I have an LED flashlight and see no leaks...hear no leaks (I heard the original leak well before I even found it)...nothing. So I get back home and let it cool off. Of course when it was cool enough, I checked the resevoir again...and it did have coolant in it...but not to where I filled it up. It was about halfway to maybe 3/4s filled (in relation to the fill line).

Now I'm a dumbass when it comes to the cooling system...but I've always known you can add distilled water to the system. Did my little acceleration test with the Neon boil off some water? Did the system settle and it turned out that there still wasnt enough even though I filled it?

I think its time for a flush and fill and an oil change anyway...I dont seem to have harmed the car just yet...but I know if I dont keep up with this, there could be a boom...and a second LL0 down the tubes (first died due to too high of oil consumption).

Thats been my night...the fun just never ends with this car. :D Any help would be appreciated! And yes...if it helps you any...you can call me a dumbass! :D

[macaroo]

I must be missing something... I just spent the better part of an hour trying to figure out where the ECTS exactly is on my wife's 1993 SOHC SL.
1. I removed the air intake as per Wolfman.
2. located two sensors on the engine itself the slightly raised one had a single wire. The lower one had a two wires, one of which was yellow as I recall.
3. both sets of wires ran into a huge grouping of wires all tightly taped up.

By the look of the new sensor my wife purchased from Canadian Tire, (single wire, brass fittings, only about 8 inches long) I fugure I MUST be looking in the wrong place. Everyone is talking about how to pinch it out of one area and just connect it. Do you actually need to remove all the electrical tape and bundled harnesses?
Is the harness to replace this thing in the bundle of wires... that makes no sense.

The best photo i could find is here. http://img55.photobucket.com/albums/v169/auxmike/DSCN0551.jpg
but as this is a SOHC, and a different year, this is not much help. If anyone can help me out on this i would appreciate it as I just sent my wife to the mechanic to get it done for 85.00 cdn. the time is 10:21am PST i have about 45 mins before committing to the mechanic.

mac

[David 93 SL2m]

The EGR valve in macaroo's picture of his 1993 SOHC SL doesn't look right. I thought the S-Series didn't start using the linear EGR valve until 1994 for some parts of the US (such as California) and 1995 for the rest of the US and Canada. What do you all think...? :|

Here is his picture:
http://img55.photobucket.com/albums/v169/auxmike/DSCN0551.jpg

[96SServiceLight]

I have a 96 SL2. Do I need to disable the air bags before replacing the ECTS?



The ECTS is a two wire sensor used by the PCM to measure engine temperature and set engine/transaxle operating parameters accordingly. On 91'-95' SOHC and DOHC engine equiped "S" series Saturns, there is a SEPERATE sensor used for the gauge. On these cars, the ECTS is the TWO WIRE sensor located just below where the upper radiator hose attaches to the engine. (The other ONE WIRE sensor nearby is used for the gauge) On 96'-02' SOHC and DOHC engine equiped "S" series Saturns, the ECTS is in the same location, but also operates the temperature gauge. (The other one wire sensor is deleted)

To change the ECTS in either case you'll need:

13mm DEEP WELL socket (6 point variety recomended)
and a socket wrench.
Perhaps a pair of needle nose pliers

Obtain the "NEW style" all brass ECTS from SATURN, it will come ready to install with nothing else needed.

DO THIS ONLY ON A COLD ENGINE!

Proceed as follows:

Remove the air snorkle running from the front of the car to the throttle body. (Or air filter housing on 91'-94' SOHC)

Locate the ECTS as described above, the electrical connector is held on by a plastic connector with two little "ears" on it that grip the lip of the ECTS. It can be hard to see. To remove the connector, SQUEEZE the plastic hood about 3/8 in. BELOW WHERE THE WIRES GO IN with either your fingers or needle nose pliers and GENTLY pull away from the engine. DO NOT PULL ON THE WIRES! If the connector does not easily release, reposition your fingers (or the pliers) and squeeze/pull again. Eventually you will find that "magic spot" and the connector will come off quite easily.

Inspect the inner portion of the connector for any signs of corrosion. If corroded, it should be REPLACED (Available from Saturn) but cleaning it can sometimes do the trick.

Remove the coolant resevoir tank cap to relieve any pressure in the system, then put it back on TIGHTLY to avoid excess coolant loss when the sensor is removed.

HAVE THE NEW SENSOR READILY AVAILABLE BEFORE THIS STEP!
Using your 13mm deep well socket, remove the old ECTS from the engine by turning it counter clockwise. Keep the socket as straight as possible over the sensor. (When it comes free from the block, some coolant will spill out, DON'T PANIC)

Quickly thread the new ECTS into the hole BY HAND to minimise coolant loss and prevent crossthreading.

Using the 13mm deep well socket, tighten the new ECTS into the engine by turning it clockwise. Keep the socket as straight as possible over the sensor to avoid damaging it. Keep turning until you feel it "bottom" in the hole but DO NOT OVERTIGHTEN IT!

You reconnect the electrical connector by placing it over the end of the new sensor and then GENTLY pushing in on it while SLOWLY rotating the connector. When everything lines up, it will then just pop into place.

Reinstall the air snorkle.


NOTES:
Coolant loss will be minimal but messy. You should NOT need to top up the coolant as less than an once or so will leak out. You "can" rinse off or mop up the spilled coolant if you wish (recommended) Keep PETS AWAY some (green) antifreeze is POISONOUS to them but tastes "sweet".

You "should" reset the PCM after changing this (or ANY sensor) this does NOT require any special tools, just disconnect the NEG battery cable for about 15 secs.

When remeoving the electrical connection from the sensor, TRY using your fingers FIRST (a little contortionary talent helps) use pliers as a "last choice"

DO THIS ONLY ON A COLD ENGINE!

[edlee]

You should not need to disconnect anything extra if you disconnect and remove your car battery. Removing the car battery makes it easier to access the engine coolant temperature sensor as well. I use a socket wrench with an extension to reach the bolt that holds down the battery closest to the engine.

[Grandpa Joe]

Hi all,

This is my first time posting here and am looking for help with my father's '98 SL1. Immediately after we start the car the temp guage goes to the halfway mark. The car sometimes sputters and dies, but will usually restart after a short wait. I picked up an Actron OBDII code reader when they were on clearance at Kragen Auto Parts for $19. Great deal. The only code it shows is P0117. I replaced the ECTS and the thermostat and that hasn't solved the problem. Is there anything else I can check related to code P0117 that could be causing the problem?

A few things to note: I did not (yet) replace the pigtail connector for the ECTS. We mistakenly did not disconnect the battery terminal before doing the procedure. How important is this, and would it help to do it now? Also, when replacing the ECTS, I learned that my father had been using only water and no coolant in the system. He did this because he said it was using water too quickly (not leaking) and didn't want to keep loosing costly fluid. Where could the water be going, and could this lack of coolant in the system be affecting the sensor and possibly triggering the P0117 code?


I appreciate all the help anyone could give.

Thanks in advance,
Ken