So, I've been having a strange problem with my car when I try to start it. This problem has been happening on and off for the past few weeks, immediately after installing solid shifter base bushings . I have taken it in to the dealer where one of my friends work and he wasn't able to pinpoint where the issue is originating. So, I come to you guys in the hopes that I'm not the only one who has experienced this problem and hopefully some of you may have some suggestions of what to fix in order to make this go away. I have not had the ignition recall done yet, it will be done sometime this week when they can fit me in.

So, on to the problem at hand, which I don't think has anything to do with the shifter bushings since I didn't have to unplug any wires. When I try to start my car the security light comes on for about two seconds and then goes away. When that happens it also, about 75% of the time, flashes service airbag, the other 25% of the time it doesn't flash anything after the security light but the car still won't start. Also, every once in a while it will also flash power steering with airbag message. The oddest thing, though and the reason I haven't let the dealership have their way with it, is that when it finally starts up normally it doesn't flash any warning messages, which leads me to believe that nothing is truly wrong with any of the parts in question. I am leaning towards it being the BCM, the SIR or the PCM on their way out.

Here is a video of when I turn the key to the run position and leave it:
You'll notice that after about two minutes all the lights light up like normal except for the fact that it is flashing the service airbag message. Also, during that two minutes you will notice that it flashes a few other messages that don't stay for long, and worry me that it is a computer problem more than a sensor issue.

Here is another video showing more of what it is like on a day to day basis:
You'll notice in this one that it does the security light thing and the warning messages, but after a few key turns in and out of run everything lights up just fine and the car starts without any trouble and has no airbag messages.

Another reason, why I am posting this here is because I have had the car shutdown on me twice, luckily it was on side streets, but when it did, it flashed service esc and power steering but no the airbag and the car started up just fine after that.

Also, here is a list of codes that my friend was able to pull from the various computers, maybe by looking at the certain codes that are here one of you will be able to help me pinpoint the issue before I spend a boat load of money on this.

PSCM:
C0845 06
BCM:
U2172
U2129
U2113 00
U2111 00
U2108 00
U2105
TDM:
B3055
SIR:
B1370 06
B0081 71
PCM:
P0628

Again, the only thing that was changed the day that all of this started were the shifter base bushings, which I wouldn't think that could cause any of this.

Also, sorry for the wall of text, and any help is appreciated.

 

Couple of things to look at before you install a new BCM. ($194.79 ACDELCO Part # 216171 )

You said you installed shifter base bushings, did you disconnect a ground? Come in contact with any wires that may have accidentally been cut? Have you tried going back to the old bushings to see if the problem goes away?

The thing that has me convinced this is a wiring/ground issue is the fact that the lights are flickering in the first video when the key on, flickering and dim as well. CANBUS systems are very very very sensitive to ground problems or residual voltage issues. Any sort of interference or shorting of something in the wiring harness ANYWHERE along the system will throw the whole car into chaos.

 

I didn't mess with any of the wires in the center console, as far as unhooking anything or cutting them, but I did have to unhook the holding clip that holds them to the shifter bracket and move them to the side in order to get the bracket out. I didn't disconnect any grounds, that I know of, while doing the swap. Are there any other grounds in that area besides the one right below the e-brake handle? Also, funny story about the bushings, the ones that were in there when I took the bracket and everything out, happened to be solid, which the previous owner never told me about. So, I decided that since I paid for the new ones and it would cost more than the worth of the bushings to send them back, I would use them, plus they fit better than the ones originally in there.

I will take a closer look at the bundle of wires to see if there is anything out of place when I get off work tomorrow.

 

I am correct in assuming that this problem started immediately after you installed the bushings, and when I say immediately, like the very next time you put the key in the ignition? Common problem with these new GM's is wires being broken literally inside the rubber jacket anywhere on the harness, ive seen this in particular where engine connectors are. I mean its very well possible that your BCM is bad, maybe shorted out somehow, I dont know, but i find it very interesting that you would do bushings and then have a problem immediately after. Usually when that happens you have to back trace your steps to find what may have gone wrong.

 

Yeah, it happened immediately after the install, everything was ok, and didn't show any signs of something being wrong, up until that point. Do you know if the run of wires from the BCM to the SDM module right below the e-brake can be replaced by myself without having to go to the dealer?
Thanks for the responses, I've never really dug into the electrical aspect of cars yet, other than audio, so all of this is foreign to me.

 

It looks like it is #15 in this picture: RELAYS & MODULES/BODY. Fits: 2008 Chevrolet Cobalt LEVEL 4 PERF/SC (SS) 2 DR | Nalley Buick GMC Brunswick
I just can't find a part number for it.

 

I doubt that harness is even sold by GM let alone it being a replaceable section. It's really going to require a bit of inspection to see where there might be a problem, check the connector at the bcm for any loose connections where it goes into the main connector, check for any cuts in the harness at all, although its probably unlikely as i think most of that section has loom around it. I would suspect something literally at the connector itself. I had an issue with my old integra where the pins inside the connector at the 3 ECU plugs would wiggle, especially if someone was in the passenger seat and had their foot resting on the kick panel where the ECU was, everytime the pins wiggled inside the connector, my AFR would change a full point on my gauge and the car would stutter. I had to replace all 3 ECU connectors and fill the back of the connectors with a clear silicone to prevent them from moving inside the connector.

 

Alright, thanks, I'll definitely look through it with a fine tooth comb tomorrow, hopefully there's nothing too terribly wrong with it.

 

Worst case scenario the BCM is shorted out and fried, you can buy the BCM on rockauto, but it will likely have to be programmed, as I believe that is what holds the programming for the keys and keyfobs. I gotta be honest with you though, most cobalt's that I see with electrical gremlins like these don't end well.

 

Before you get to freaked out go back and check only the things you touched. Completely rule them out before you get into anything else on the harness. Three more thing you get into the more likely you are too scree something else up. Like spawns said these cars are very sensitive to bad grounds. Check that before anything.

 

Did you do any dash/console work? I mean did you disturb any plastic inside the car....

If you then you may have pulled on a wire or plug.

Like the other two said retrace your steps.

 

Id like to see if your issue gets fixed once you have the ignition replaced. My car does some funny stuff too on occasion and im thinking it may be the ignition since it recently **** out on me and wont turn at all.

 

May sound dumb but check your batter cable lugs. I had one snap off for no reason aside from possibly a bad crimp. It gave me similar issues to what you are having. Since it was still touching but broken