cobalt electronics problem

[gearbolt]

I have a 2007 chevy cobalt with 90k miles on it. I bought it brand new and have never had any issues with it until the other day. I was driving down the freeway and the power steering randomly shut off, the dash gauges started going crazy, the transmission shift assist shut off and it began shifting real hard and jerking...o and the worst part? the check engine light came on!!

I proceeded to bring it to the dealership thinking I have no worries because of that golden "100k mile bumper to bumper warranty" I bought. Wrong!
2 hours later they charge me 200 bucks and tell me that they found the problem. The negative battery terminal was loose and they went ahead and tightened it for me and everything should be good. I left annoyed but also glad the problem was fixed....Wrong! 2 days later same problem occured. My car now sits in a park and ride. Can anyone help me out with this problem or just maybe reassure me that I should be pissed at this crappy dealership for the BS they put me through?

 

[Tuner923]

your descriptions of symptoms seems to vary between threads.. so what type of work had been done to the vehicle before these "symptoms" started? custom stereo, sound system install, aftermarket fog lights, remote starter, anything electrical related?

 

[white balt]

Did you get you power steering motor replaced?
There was a huge recall on power steering motors for all cobalt.

sent from my inspire!

 

[gearbolt]

Aftermarket radio installed, thats about it. And yes I did the recall about a year or so ago...but when I brought it in, the service manager said people were having alot of problems similar to this even after doing the recall.

 

[Tuner923]

any chance the radio install was a hack job? My stock radio is connected to the BCM and is multiplexed to receive inputs from vehicle speed sensors(speed sensed volume control and Dimmer input from the ambient solarsensor). I assume the base models had at least this minimal feature. Either way a signal to the BCM is getting fudged from something somewhere. someone needs to start some daig on it with a labscope.

after thought: Of course the stock radio is connected to the BCM silly me for doubting it. when you shut the car off and open the door, radio goes off right? that's a result of the switch in the door jam sending a signal to the BCM to shut it off... (thinking out loud)

 

[gearbolt]

Tuner923-- I think you just saved me! I installed the radio myself. Have installed many car radios but am in no way professional. Everything went smoothly except for one wire which did not match anywhere on any wiring diagram and did not match on the wiring harness. I connected it to the last wire that was left over, thinking it was the only plausable solution to the problem. I have had problems with the radio when the sunlight comes up in the morning, the radio would sometimes turn off. Would this cause so many other electrical problems such as power steering failure and the like though? Also, I have had this radio installed for 6 or 7 months with no problems whatsoever...Did I finally just blow something because of an incorrect wiring connection?

 

[Tuner923]

I'm not going to say for sure that the radio is the exact cause. Though it is most certainly an avenue that should be further investigated. Other things to check include looking for corroded/loose connectors, wire conditions, battery voltage under load. you said the CEL came on.. what was the code? was it a Body module code?

Electronic Diag is really nothing more than process of elimination and some educated guessing there is NO manual or procedure to diagnose electrical complaints it's all intuition and experience.