The check engine light and the Traction failed service stab sys popped on exactly 4 days after we bought this 2006 with 120k miles.

Advance auto won't scan codes because they are scared of the chinese virus and Autozone could only get a P0113 and a P0128

They say that their system will not get the bcm codes. I don't know if that is true or not.

Anyway, should I just order a new thermostat, coolant temp sensor, and MAF from Rockauto? I can get all the parts for less than a dealer scan fee.

I also took it to a car wash and sprayed the engine bay a little after the check engine light but before the traction failed light.

 

@bassackwards admittedly a novice here BUT learning as I go...

sounds like you have some work cut out....check out this thread (it was re the full suite of repair guides, sounds like that might help you) BUT also look at the other comments re a scanner (I don't know much about as I haven't a need but maybe send a msg over to that poster to get more info)

https://www.hummerforums.com/forum/h...ide-oem-43208/

 

HUMMER DTC P0128

Make:HUMMER Code:P0128 Definition:ECT Excessive Time To Enter Closed Loop
Description DTC P0101, P0102, P0103, P0112, P0113, P0116, P0117, P0118, P0500, P0502 and P0503 not set,
ECT sensor less than 158ºF at startup, IAT sensor more than 19ºF, MAF sensor from 24-75 g/sec with the average more than 15 g/sec, engine run time from 120-1600 sec Cause:

• Check the operation of the thermostat (it may be stuck open)
• Coolant level is too low, or the coolant mixture is incorrect
• ECT sensor signal circuit has a high resistance condition
• ECT sensor is damaged or it has failed

Hummer H3 P0113: IAT Sensor → High Input Problem
IAT Sensor 3.5L Testing

 

Firestone pulled the codes for me again. Now I just have the P0113 and a host of other codes.

C0306
C0327
B0790
C0186
C0268
C0276

I guess a couple of these could be caused by the yaw sensor but I can't find it. Driver side floorboard is wet and the sunroof flooded me in a heavy downpour today.

 

Firestone can't trace/repair the open wire to the IAT? 1 step at a time, fix the IAT sensor wiring, clear codes, in the meantime dry the interior then scan for codes again.
Btw, your chassis codes point to the tccm (#3):

 

I didn't ask them to fix it, just scan for codes. Interestingly the P0128 was gone.

I thought that the P0113 code meant that the voltage was too high. A broken wire would be too low right?
BTW someone installed a K&N intake tube and a cone filter at one time. I'm not as worried about the P0113 code as all these others that seem more expensive to fix.

Can all of these codes be erased temporarily ? It seems odd that I got all these at the same time unless the problems already existed.

This truck has sat outside in TN downpours for weeks, it seems odd that they come up after we get it home.

When I shift from 4hi to 4hi lock I don't hear any noise, should I? 4 low works as it should I think .

 

How To Test The Intake Air Temp (IAT) Sensor (GM 3.5L)
DID YOU CLICK ON THE >>>BLUE TEXT<<< I POSTED ABOVE? (posted again,6pages read and learn)All you need to correct all your codes, is multi-meter, soldering iron and/or electronic contact cleaner.

diagnostic trouble code P0113 (IAT Sensor Circuit High Voltage) that you retrieved from the PCM's memory is right on the money.

The most likely cause will be that the circuit is ‘open’ somewhere inside the MAF sensor (remember the IAT sensor is part of the MAF sensor assembly).

To be a bit more specific, by ‘open’ I mean that somewhere in the two wires or the IAT Sensor, there's a break in the wire or that the IAT sensor is fried.

 

I haven't even messed with the IAT sensor yet being that yesterday was a holiday and today was Sunday. While I was out I just stopped by and got it scanned to hopefully learn more about the traction failed issue.

We did change out the transfer case fluid before this started. It looked like a strawberry milkshake. We replaced it with Dexron VI.
We sprayed everything pretty well with a high pressure car wash to clean all the oil and funk off the front diff and brake rotor areas from a transmission cooler like leak. The trans was overfull so I'm sure that someone knew about the leak already.

I inadvertently unplugged the encoder motor while the key was on and caused a 4wd fault that seems to have self corrected.

I am not hearing any noise at all when shifting between 4 high and 4 high lock

 

While P0113 is not going to leave you stranded on the side of the road, it is important to not ignore it. If you allow your Hummer H3 to run lean for too long of a period of time, it’ll develop other problems with the engine.

 

I get that. It is not a daily driver yet. Some of these other codes seem major and I'd like to correct them as well.