"CES" Light on but Cant Pull Codes??? - Chevy Cobalt Forum / Cobalt Reviews / Cobalt SS / Cobalt Parts
Problems and Service Talk about any mechanical problems you are having

Closed Thread
 
LinkBack Thread Tools Display Modes
post #1 of 54 (permalink) Old 08-31-2012, 01:52 PM Thread Starter
Newcomer
 
Join Date: Aug 2012
Posts: 15
"CES" Light on but Cant Pull Codes???

Hello, This is my first post but not my first problem w/ this Cobalt. I start the car and the CES and TC light are on and POWER STEERING is displayed on the cluster. The electric assist steering is inop and I also notice the tach needle twitching while engine is running. The park brake indicator light flickers as well as the DRL's. I attempt to drive the car and the trans shifts very hard and prematurely shifts into OD so the car lugs.
I attempt to pull codes w/ my scanner and communcation link failure is shown. I borrow another scan tool with the same end result. I cant seem to communicate w/ the PCM...
-All fuses check good (w/ test light)
-Have power on pin 16 at DLC and ground at pins 4 and 5 at DLC

One question that I have is: Do all these problems share a common ground that could be loose?
I have looked at all the TSB's I can find and nothing matches.
I have read of come corrosion issues at the UHFB but nothing official.

I know there are some very sharp techs on here and I thank you in advance for any help.
Ben
1972cst is offline  
Sponsored Links
Advertisement
 
post #2 of 54 (permalink) Old 08-31-2012, 02:58 PM
Super Moderator
YourCobalt.com Premium Member


 
Coby7's Avatar
 
Join Date: Oct 2011
Location: Magnetic Hill, New-Brunswick
Posts: 11,820
Garage
What year? Bet it's a pre 07.

Every minute spent angry is a happy minute lost for ever and ever!!!
Drives 2016 Cocoa Buick Encore 1.4L Turbo auto KL4CJDSB2GB652675
Drives 2016 Sunset Orange Trax LT1 1.4L Turbo auto 3GNCJPSB8GL142716

Never drive faster than your guardian angel can fly
Coby7 is offline  
post #3 of 54 (permalink) Old 08-31-2012, 03:28 PM Thread Starter
Newcomer
 
Join Date: Aug 2012
Posts: 15
Im sorry, I should have been more thorough... this thing has made me a little !
2006 Cobalt 2.2 auto

Last edited by Coby7; 08-31-2012 at 07:42 PM. Reason: deleted one space to many.
1972cst is offline  
 
post #4 of 54 (permalink) Old 08-31-2012, 04:05 PM
Super Moderator
YourCobalt.com Premium Member


 
Coby7's Avatar
 
Join Date: Oct 2011
Location: Magnetic Hill, New-Brunswick
Posts: 11,820
Garage
OK, makes sense now because an 07 up would not run with Open "ECM" ground. 05-06 ignition module is seperate from "PCM" which is the reason yours even starts. You probably have an open "PCM" ground.(G105) this would make all your present failures make sense. G105 is on the transmission case just as it butts to the engine block visible in the front. G103 is bolted to the sub frame below drivers side headlight or ABS module if you have one. I've posted G107 but ignore it for your problem.
If you lose your "PCM" ground you can't pull codes because OBDII as lost it's signal path.





---------- Post added at 07:05 PM ---------- Previous post was at 06:54 PM ----------

For trouble shooting try grounding the "PCM" case to see if symptoms disappear.

Every minute spent angry is a happy minute lost for ever and ever!!!
Drives 2016 Cocoa Buick Encore 1.4L Turbo auto KL4CJDSB2GB652675
Drives 2016 Sunset Orange Trax LT1 1.4L Turbo auto 3GNCJPSB8GL142716

Never drive faster than your guardian angel can fly

Last edited by Coby7; 08-31-2012 at 07:41 PM.
Coby7 is offline  
post #5 of 54 (permalink) Old 08-31-2012, 07:43 PM
Super Moderator
YourCobalt.com Premium Member


 
Coby7's Avatar
 
Join Date: Oct 2011
Location: Magnetic Hill, New-Brunswick
Posts: 11,820
Garage
Any more questions? Might have forgotten something.

Every minute spent angry is a happy minute lost for ever and ever!!!
Drives 2016 Cocoa Buick Encore 1.4L Turbo auto KL4CJDSB2GB652675
Drives 2016 Sunset Orange Trax LT1 1.4L Turbo auto 3GNCJPSB8GL142716

Never drive faster than your guardian angel can fly
Coby7 is offline  
post #6 of 54 (permalink) Old 08-31-2012, 09:20 PM Thread Starter
Newcomer
 
Join Date: Aug 2012
Posts: 15
Quote:
Originally Posted by Coby7 View Post
Any more questions? Might have forgotten something.


Just one more question Coby... how do you do that?????
Your knowledge on this information baffles me! You must work in tech support or something.
I will try to supply a temporary ground to the ECM for testing purposes. Where is the ECM exactly? There are two modules mounted in front of the underhood fuse block. I think the big one is what Im looking for???
1972cst is offline  
post #7 of 54 (permalink) Old 08-31-2012, 09:31 PM
Newcomer
 
HerBalt's Avatar
 
Join Date: May 2012
Location: Kelowna BC Canada
Posts: 15
The one the cover clips on to. a quick way to check if its the ecm ground is to run a wire right to the metal shell of it to a known ground. Just tape it (temporarily obviously) and start the car. if it all goes away, thats your culprit. If not, double check your new ground before moving on to more trouble shooting.

Coby7 is an amazing asset to this site!
HerBalt is offline  
post #8 of 54 (permalink) Old 08-31-2012, 10:00 PM Thread Starter
Newcomer
 
Join Date: Aug 2012
Posts: 15
Ok just tried grounding the ECM case to a known ground w/ alligator clip jumper wire and nothing changed. All problems still present, cant communicate w/ scan tool either.
1972cst is offline  
post #9 of 54 (permalink) Old 08-31-2012, 10:55 PM
Expert
 
Join Date: Apr 2011
Posts: 985
Garage
try the same thing as above with the PCM. I dont know if its a metal case or not.
You could always check the actual ground connection as well, but if its insulated wire you may not see a break in the circuit, so that grounding trick will tell you if the PCM is indeed the culprit without having to replace the whole ground path.
acoutu is offline  
post #10 of 54 (permalink) Old 09-01-2012, 06:15 AM
Super Moderator
YourCobalt.com Premium Member


 
Coby7's Avatar
 
Join Date: Oct 2011
Location: Magnetic Hill, New-Brunswick
Posts: 11,820
Garage
"PCM" case on a 2006 will all be oxidized. Make sure you clean the spot you ground to. Same with chassis ground you use. "PCM" is the module with two connectors, the one closest to fuse block.

---------- Post added at 09:15 AM ---------- Previous post was at 07:56 AM ----------

Hope this works because the other option is that your "PCM" processor has failed. Also a possibility, but the flickering headlights kinda point to a bad ground. Your sure you check the "PCM" fuse. Pull it out and re-insert to make sure the contacts are clean.

Every minute spent angry is a happy minute lost for ever and ever!!!
Drives 2016 Cocoa Buick Encore 1.4L Turbo auto KL4CJDSB2GB652675
Drives 2016 Sunset Orange Trax LT1 1.4L Turbo auto 3GNCJPSB8GL142716

Never drive faster than your guardian angel can fly

Last edited by Coby7; 09-01-2012 at 06:40 AM.
Coby7 is offline  
Sponsored Links
Advertisement
 
Closed Thread

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



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
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome