SaturnFans.com
what's new (beta) - classifieds - forums - photos


Go Back   SaturnFans.com Forums > Models > Saturn Aura > Aura General
Register FAQ Members List Groups Calendar Chat Room Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Display Modes
Old 10-17-2010, 11:33 PM   #1
Anjey
Member
Anjey is on a distinguished road
 
Join Date: Feb 2005
Location: Los Angeles
Posts: 149

1996
Default temp & cooling questions - sensors wiring

Please help me figure an intermittent cooling problem in my 2007 Aura XE.

The temperature gauge shows slightly over the center mark sometimes and sometimes it is just above the 1/4 mark.

It has nothing to do with the outside temperature, it does that when cold and it does that when hot.

I noticed the following:

1) When driven on a FWY the gauge tends to move above the center mark and stays there. Typically on a flat surface or when I drive down hill with the RPM up to 2000 and a little acceleration.

When the slope changes and the car down shifts and the RPM is between the 2500 to 2900 the engine "cools down" so the gauge drops down to 1/4 mark. That occurs when driven uphill with more acceleration pedal pressed.

So for instance at 65MPH, 75 F outside during driving from Las Vegas to Los Angeles, with the drive train hot, the speed is constant, outside temperature constant. Only RPM changes and the gauge reading changes.
The pattern is: more load on the engine - cooler, less load - hotter.

2) During city driving there is absolutely no pattern in which the gauge goes up. But when it crosses the middle mark - it tends to stay there all the time.

3) There are times the gauge won't ever go above the center mark no matter how I drive and how hot it gets outside. Sometimes I drive a 100 miles and the gauge won't move from the 1/4 mark.

4) When the gauge is above the center mark, the fans on the radiator are ON, the speed is low (because they don't make much noise) I can hear them only when I lift up the hood.

5) When the gauge is over the center mark - the car won't 'cool down' by just sitting idle. The car can idle for 5 minutes with fans on, outside temperature at 65 F and the gauge reading won't drop down a bit and stays at the center all the time.


Therefore I'd like to ask:
- which sensor controls the gauge?
- Which sensor controls the fans?
- What controls the fans? (ECM or just a separate relay with a temp sensor)
- which temperature turns on the fans? - meaning which temperature triggers the LOW speed and HIGH speed fans?


Is it possible that the gauge is bad?
How do I figure if the engine is hot - or is just showing incorrect gauge reading?
Can a broken gauge cause FANS to turn on?
Can anyone provide a circuit diagram for the temperature gauge and the sensors and explain how that system works?

Please help me with this problem, because the dealership was unable to fix it 3 times - the car has overheating history, the coolant reservoir exploded once and was replaced under warranty and there was once a leak from a hose - another warranty repair - the coolant can be smelled inside the cabin and it leaves residue on the inside of the windshield. The coolant is being added during regular oil changes.
The car is still under warranty but was diagnosed at a GM dealership and they found no problems.
Last time they left it at iddle for couple of hours and the gauge didn't go over the center (at least that's what they told me)

Any suggestions?

Last edited by Anjey; 10-17-2010 at 11:46 PM..

REWARD EXCELLENCE!

Add to Anjey's Reputation
Rate the quality of this post and help Anjey reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
Anjey is offline   Reply With Quote
SaturnFans.com Sponsored Links
Old 10-18-2010, 09:43 AM   #2
Low Saturn
Super Member
Low Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to beholdLow Saturn is a splendid one to behold
 
Low Saturn's Avatar
 
Join Date: Aug 2003
Location: San Jose, CA
Posts: 15,271
 

2008 AURA XE
Default Re: temp & cooling questions - sensors wiring

Quote:
Originally Posted by Anjey View Post
- which sensor controls the gauge?
The engine coolant temperature sensor (ECTS)

Quote:
Originally Posted by Anjey View Post
- Which sensor controls the fans?
The engine coolant temperature sensor (ECTS)

Quote:
Originally Posted by Anjey View Post
- What controls the fans? (ECM or just a separate relay with a temp sensor)
Input from the engine coolant temperature sensor to the ECM. Then ECM then takes those readings and determines when to turn the fan on.

Quote:
Originally Posted by Anjey View Post
- which temperature turns on the fans? - meaning which temperature triggers the LOW speed and HIGH speed fans?
I'd have to look that one up in the service manuals.

Quote:
Originally Posted by Anjey View Post
Is it possible that the gauge is bad?
Anything is possible.

Quote:
Originally Posted by Anjey View Post
How do I figure if the engine is hot - or is just showing incorrect gauge reading?
You need to connect a scan tool to the car. You'd need to compare what the actual temperature being read by the sensor compares to what the readings on the gauge say. But before you do that, you need to know what each mark on the gauge corresponds to what temperature reading.

I'd start by connecting a scan tool to the car before its driven. Engine temperature should be pretty close to the ambient temperature outside. The drive the car normally for 20 minutes or so. Take another look at engine temperature. It should read the whatever the accepted operating temp of the engine is. I don't know exactly what that is right now, but it should be around 220 degrees.

Quote:
Originally Posted by Anjey View Post
Can a broken gauge cause FANS to turn on?
No. If the fans aren't turning on at the proper temperature or time, I'd suspect a bad or faulty engine coolant temperature sensor, relay or relays.

Quote:
Originally Posted by Anjey View Post
Can anyone provide a circuit diagram for the temperature gauge and the sensors and explain how that system works?
Its a pretty simple system. Readings from the ECTS are sent to the ECM. The ECM has predetermined values of when the fans turn on and off and at what temperatures. Once those values are reached, a signal from the ECM is sent to a relay which triggers the fan or fans to turn on.

Most of those steps will be overridden by turning on the A/C.

...
Mike

-1991 Turbo SL2 - Gone, but not forgotten.
11.809 @ 116.488 mph
www.differentracing.com

-2001 Chevrolet Suburban
-2011 Rally Yellow Chevrolet Camaro 2SS RS

REWARD EXCELLENCE!

Add to Low Saturn's Reputation
Rate the quality of this post and help Low Saturn reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
Low Saturn is offline   Reply With Quote
Old 10-18-2010, 02:01 PM   #3
golftango
Senior Member
golftango is on a distinguished road
 
golftango's Avatar
 
Join Date: Jan 2003
Location: CT
Posts: 1,685
 
Default Re: temp & cooling questions - sensors wiring

I know some other GMs (HHR comes to mind) has the coolant temp when scrolling through all the menu items on the OBC. Can this be retrofitted into the Aura? Programming?

...
'12 Honda Pilot EX-L & '13 Suzuki Kizashi S 6MT

REWARD EXCELLENCE!

Add to golftango's Reputation
Rate the quality of this post and help golftango reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
golftango is offline   Reply With Quote
Old 10-19-2010, 12:11 AM   #4
greenman
Senior Member
greenman is a jewel in the roughgreenman is a jewel in the roughgreenman is a jewel in the rough
 
Join Date: Mar 2010
Posts: 1,923

2009 AURA XE
Default Re: temp & cooling questions - sensors wiring

If it's still under bumper-to-bumper I would try another dealer (if that's possible where you live). Maybe that dealer is waiting for your BtoB to expire.

Like Mike said it's a pretty simple system. Either the gauge is reporting the true coolant temp in which case you have low coolant or a bad coolant thermostat or the sending unit has gone pear-shaped & is misreporting to the gauge. A bad gauge is a more remote possibility...certainly a more complicated repair.

Since you are adding coolant you have a leak somewhere. How much are you having to add? If you have coolant odor inside the cabin it's quite possible your heater core is leaking (& you do not want to have to pay for that repair...trust me). But your car is pretty young to have a leaking core.

They did change the coolant thermostat right (cheap & easy to do on most cars)?

Last edited by greenman; 10-19-2010 at 12:18 AM..

REWARD EXCELLENCE!

Add to greenman's Reputation
Rate the quality of this post and help greenman reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
greenman is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Air temp and Coolant temp sensors the same? JonP S-Series Tech 15 03-28-2009 06:44 AM
temp sensors 02satman S-Series General 5 06-29-2008 09:24 PM
AIT & ECTS.....the same but different temp sensors? dildog S-Series Tech 7 07-21-2006 10:39 PM
'95 SC2 Temp Sensors Djets S-Series Tech 2 08-25-2002 09:51 PM
temp sensors........ darse S-Series Tech 5 01-14-2002 08:42 PM


All times are GMT -5. The time now is 02:56 AM.

Advanced Forum Search | Advanced Photo Search


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
SaturnFans.com. The Saturn Enthusiasts Site.