Does my 2000 SW2 have ABS

[GSmithFL]

Our 2000 SW2 has no brake pressure, straight to the floor. AutoZone wants to know if it has AbS. Never noticed any ABS pulsing and I can’t test it now.

Can I tell by looking under the hood? There is a silver box behind the battery, but I do not know what that is.

[billr]

Yes, you can tell by looking, and that "silver box behind the battery" is a pretty good description of an ABS module. I don't have a picture handy, but somebody else will point you to one if there is still some doubt.

What are your intentions here, are you going to try making this a DIY project? If so, give us some idea of your skills/experience and tools available.

Did this problem come on suddenly, or did the brakes slowly get worse?

With any brake problem, start by checking fluid level in the reservoir and looking under the car, behind each wheel, for fluid leakage.

Does this car have a lot of rust on the under-body? If so, look for leakage all along each brake line.

[GSmithFL]

Originally Posted by billr

Yes, you can tell by looking, and that "silver box behind the battery" is a pretty good description of an ABS module. I don't have a picture handy, but somebody else will point you to one if there is still some doubt.

What are your intentions here, are you going to try making this a DIY project? If so, give us some idea of your skills/experience and tools available.

Did this problem come on suddenly, or did the brakes slowly get worse?

With any brake problem, start by checking fluid level in the reservoir and looking under the car, behind each wheel, for fluid leakage.

Does this car have a lot of rust on the under-body? If so, look for leakage all along each brake line.

Hey billr, thanks for the quick reply.

My wife came out of work yesterday and immediately the pedal went to the floor. When I got there, I had the same result. Pumping the pedal does nothing.

The car is a rust-free Florida car, and I see no signs of leakage under the hood. The reservoir is full.

I have a mobile mechanic I usually use, but need to buy parts before he shows up. I thought maybe the box between the battery and master cylinder might be an ABS module since my ‘98 SL1 does not have it.

Should I check the lines first anyway?

[Waiex191]

Here is my '99 master cylinder. It has ABS. There are a couple extra connectors and it is large. Note all 4 tubes are inline.


My '98 does not have ABS. It has a smaller MC and the tubes are not 4 in a row. More like two pairs, with one above another. It is much like the MC in this Gen3 SL2 that I pulled a transmission from at the junkyard yesterday. You can see two of the tubes.


In this picture you can see the silver thing hanging out of the car. It is the PCM module.


Look at your master cylinder. That is the easy way to tell.

[GSmithFL]

The pics are awesome! Thanks!

I have to drive back up to the office and look at the master cylinder. I will keep you posted!

[onlinebiker]

Drum brakes in rear = no ABS.

[Waiex191]

Originally Posted by onlinebiker

Drum brakes in rear = no ABS.

Not true! Unless that is a Gen3 thing. My '99 has ABS and rear drums.

Edit: a recent thread showing rear drums and ABS on a 2000 SL1.
http://www.saturnfans.com/forums/sho...d.php?t=234862

[MobileSaturn]

Originally Posted by Waiex191

Not true! Unless that is a Gen3 thing. My '99 has ABS and rear drums.

Edit: a recent thread showing rear drums and ABS on a 2000 SL1.
http://www.saturnfans.com/forums/sho...d.php?t=234862

Correct. You can also see here that from 1999 on forward, all Saturn S-Series' came with rear drums, regardless of ABS.

[Waiex191]

Interesting link, thanks. So onlinebiker's statement is true for pre-94 Gen1s.

[fdryer]

GSmithFL, below are battery, pcm, brake master cylinder and abs unit. Autozone asked whether or not abs is used because the counter person was probably looking for two(?) different brake master cylinders. Before second guessing about abs, the most likely reason for pedal to the floor with the master cylinder still full of fluid is a worn out brake master cylinder. ABS is mechanically invisible to all brake systems because valves are closed with brake fluid passing thru the abs unit to brakes. ABS goes on standby when ignition is turned on, engine running and car driven. When emergency braking is detected where one or several wheels locks up, abs takes over to prevent brakes from locking up and takes over braking as long as the brake pedal is pressed down. When abs activates to control braking, valves open and close, becoming a visible presence in the braking system. Release brakes and abs goes back to standby, invisible to normal braking until another braking event occurs requiring abs intervention.

Was brake fluid ever replaced? Mileage of this car?

[fetchitfido]

'98-'02 had no rear disc option; only drums.

'91-'97 SC2's w/ABS got rear disc
'91-'97 SL2's probably got rear disc by default w/ABS
SOHC's I don't think had the disc option (though they should have...).
SW2's were generally treated like SOHC's as far as 'default' options go.

With a bit of work any model can have rear disc swapped on; hardest part is finding (and receiving) the correct parking brake cables.

[mattwithcats]

I thought if you had traction control, you had ABS tooo ?

[fdryer]

You are correct but GSmithFL stated not noticing abs pulsing. Many drivers are unaware of the zinging sounds abs makes as soon as a car is driven above 5 mph when abs exercises its motor as the last test before going into standby mode. Some drivers, like me are reminded from time to time, to slow down in some turns taken at higher speed than posted when braking and an uneven surface allows wheels to momentarily lose traction when abs automatically activates. The 'foot massage' when abs activates as feedback. I've taken one turn close to work where the short radius turnoff is flat, concrete and slightly rough. At a higher than normal speed when I brake at the beginning of this turn, the wheel(s) losing traction brakes and slows down faster than the other wheels maintaining traction when abs detects the differential wheel speeds and activates abs braking. I can (as well as anyone else) activate abs on sandy, gravel, pebbled, wet, icy, snowy ground as low as 10 mph. Losing wheel traction in any wheel while braking automatically forces abs to take over braking.

Traction control is the exact opposite of abs and uses the abs to deliberately reduce engine power and apply braking to the spinning wheel. Electronic spark timing is reduced then injector pulses are shortened to reduce engine power in concert with braking applied in extreme acceleration events like attempting to spin wheels from an icy patch of ground or trying to get out from a snowed in parking spot. A slipping drive wheel that's spinning faster than the other drive wheel is detected as differential wheel speeds so the abs tells the EFI system to reduce power and if that doesn't help, braking the spinning wheel occurs. Yes, braking the spinning wheel since its doing nothing to provide traction so abs brakes that wheel until it matches the opposite drive wheel. Some, including me, have felt the disconnect between pedal and engine when this occurs.

[fetchitfido]

TC requires the ABS system to function.
Exception:
'91-'94 5spd's did NOT have TC even with ABS.

TC button on 3rd gens is harder to find than on 2nd gens; not that it's actually hard to find but it's not 'right on top of the stereo' obvious either.

[fdryer]

Correct. My bad for not mentioning not every abs unit has traction control. Early abs didn't have tc due to sophistication and the importance of getting on the bandwagon with other manufacturers adding abs as standard when it was an option. My L300 may be considered a 3rd gen Saturn but a different model altogether, from its European heritage (Vectras?). Mine has abs and tc. I don't care for tc as I rarely get into extremely poor parking spots with snow covering the car the next day and rarely encounter icy slick roads where traction is lost. I count on salted roads to allow minimal traction without inadvertently sliding around.

[Waiex191]

I hated my traction control. It does not understand that to get up a steep New England hill that momentum is king. It trumps a bit of wheelspin.

[billr]

Have you checked to see if the brake push-rod is still connected to the pedal lever/arm? It is hard to imagine there is a big leak if the MC is staying full, but have you checked all over for leaks yet?

[alordofchaos]

Originally Posted by GSmithFL

There is a silver box behind the battery, but I do not know what that is.

small, flat (about as thick as a deck of cards)?

That's your Power Control Module (PCM), your car's main computer. It's only there on 3rd gens (in 2nd and 1st gens, it is under the driver side dash)

edit: NVM, I see waiex already answered the question

[GSmithFL]

Howdy y'all... as we got under the car, the leak became more apparent. It was actually a brake line that we didn't see the first day as it was raining.

I'll have to do the other side, too. But we were back on the road that afternoon.

Sorry about the slow response - dealing with a toddler takes all my internet time.

Thanks!