Temp Computer Problem? Lots of Codes and Communication issues

[NEOhio_Sonic]

Hi all. New to the forum and not sure if this is the best place to post for suggestions, but I'll give it a go. Sorry about the long text, I want to be detailed.

Had my Sonic for a little over 5 years. Nice car, no major issues. Now it's out of warranty and the issues are starting ... surprise, huh?

Drove the car home for an hour yesterday, was coming to the end of an offramp, red light, hit the brakes (was going just a smidge too fast for the offramp), hit a semi-decent sized pothole while I was stopping. I thought I felt the anti-locks kick in for a second over the pothole... odd?

Drove the last couple minutes home ... no issue other than I thought I heard a faint odd sound. Got home, turned off the car, went inside for about 5 minutes. Had to make another trip. Turned on the car ... all of a sudden the CEL (check engine light) was on, PSL (Power Steering Light) was on, the Traction Light was on, and my trip odometer had all dashes!!

Wasn't happy at that point! Turned the car off, back on, same thing. Went to put the car in reverse, gearshift worked, but car wouldn't go. Was like I was in neutral. Put it in drive and that worked, although roughly. Power steering did NOT work at this point.

Turned the car off, restarted, same thing!!! Worried now. Went in the house, called a few people, waited 15 minutes, went and started the car, everything seemed fine EXCEPT the CEL was on. The other lights were off and all parts of transmission / power steering worked fine!

Drove the car for 10 minutes, stopped, started, fine, except for CEL. Stopped at AutoZone, they put the code gizmo on it and said it had about 5 or 6 codes dealing with communication; "Lost comm. with PS module", "Lost comm. with trans. module", "Lost comm. with Fuel Pump module", etc.

By the time I was done talking to him and he went back in the store, I started the car again and the CEL light was out. Car ran fine on the way home.

The last two years I've had nothing but issues with the GM service department where I bought the car, I don't want to go back there.

Any ideas what this sounds like? To me, I'd guess when I hit that pothole braking a little harder than I should've been, the computer dropped all it's communications for a moment? Again, I had no problems until 10 minutes later after I got home and stopped / started the car.

All seems to be working now. I don't have the extra funds for random diagnostics and made-up issues from the dealership, but not sure what to do. Any suggestions would be appreciated.

Thanks in advance!

 

[gnonne]

Similar situation on my wife's 2012 1.8 auto sedan happened last winter. Drove it for hours then parked overnight, outside temp was about 0 F. Next morning started fine, drove 45 min to a store and parked. It was about -15 F at the store and the car cooled down very quickly while I was inside for an hour (I later found the t-stat was going bad.)

Came out and every light lit up, would not engage in gears, etc. Restarted a few times and eventually got it to drive with CEL on. Stopped at a parts store, they scanned half a dozen communication codes, then light went out.

Car has run fine ever since.

I think we both had the same issue. The harness jarred loose for a fraction of a second, in your case due to the pothole, mine due to the temperature drop.

Not much can be done about this. Maybe you could have a trusted tech pull the major harness connectors and put them back together with dielectric grease, but that's about it.

 

[NEOhio_Sonic]

Hi,

Thanks very much for your reply. I did a quick search before I posted in the forum, and I think I saw you may have posted this under "Christmas Lights" or something to that effect It sounded like the same problems, but with a different cause. I'm glad to hear the car ran fine after that. I think I'm going to run this for the weekend, and if there's no problems, just go with it. If I get a few extra $$ in the coming months, I will probably do as you suggested and try to find a decent mechanic and have him look at the wiring harness connector(s).

Thanks again for the suggestion, and have a great day!

 

[OssiansFolly]

The harness jarred loose for a fraction of a second, in your case due to the pothole, mine due to the temperature drop.

This was the first thing I thought. A harness somewhere slipped. I'd just go back through things under the hood and under the car to make sure everything you can see is snug. Just double and triple check them all.

Also, hello fellow NE Ohio person.