I am fixing an '06 H3 for a friend. She hit a tree awhile back, dislocated the drivers front wheel from the truck, it sat for about year and a half or so (outdoors in Florida) before i got parts to fix it. I have all the mechanical stuff fixed, it starts ... sometimes ... runs/drives/stops, abs light is off, everything seems ok on low speed drives.

But when I scan it, I get 40 OEM Hummer diagnostic codes and 6 body codes. Every sensor is represented in the codes, IAT, MAP, ECT, O2's, MAF, fuel trims, etc. The weird this is, I get a bank 1 lean and rich code, maf sensor high and low code, ect coolant low code (but its totally full). It's like every single code that could be present, is.

Where do I start? Is it a wet/corroded terminal BCM? I highly doubt every single sensor went bad.

There was a leak I noticed once while moving it, but the drivers front tire was removed, so it was leaning away from the BCM, and that's where the water was pooled. What kind of electronics are located on the drivers kick panel side, or around the transmission hump?

 

I've mostly worked on old school stuff, like '60s and 70s cars. Converted my '66 mustang to EFI with '90 mustang wiring harness/ecu and aftermarket programming and maf/throttle body. So I understand the concepts. Does an obd2 car need to be driven after a lengthy time with no power to relearn all the highs and lows for the sensors? Do I need to perform the 4 GM drive cycles and maybe these codes will clear themselves? Just really have nowhere to go here. I don't want to throw parts and/or my time at it.

 

Check the oem battery terminals! The H3 is very sensitive to Low voltage/poor connectivity at the terminals and it acts weird so start there!

 

If it has a sunroof and leaked, likely the BCM got wet, even if there was no puddle on that side.

You did not mention the battery, after sitting hooked up to a vehicle a LONG time they can be damaged.

 

It sat without a battery. It has a brand new one now. I believe it does have a sunroof, but I do know for a fact that there was a leak in there. Haven't pulled the BCM out to inspect it for corrosion or signs of water intrusion.

There's no check engine light, the service stability system went away after I drove down my driveway and got above like 15mph, nothing in the dash info center, truck runs normally (have the passlock starting issue though). I suppose a wet BCM could cause some issues that are unexplainable huh? Just weird that there's 40+ error codes and no check engine light, lol

 

Replace the bulb on your check engine light!

 

lol

all the lights work, they are illuminated when the key is in the acc position before trying to start.

I didnt sign on for all of this, I was here to just fix her wreck damage. Think im gonna package this one up and send it off. lol

 

Did you clear the codes, drive and check for codes again?

 

Customer: I now have major problems with my car!
Service Advisor: When did you first notice there was a problem with your car?
Customer: Over a year ago.
Service Advisor: We will repair it, and it could be costly. There's another option, the auto salvage will take it.