So I've just pulled an upstream sensor, the '05 connector is D-Shaped, whereas the '08 is rectangular, plus the pin assignments are different, it's Pin-E on an '05.

The heater measured 3.2 Ohms, however Pin-E has no connectivity to GND so it cannot be used as I suggested.

So hummerz is correct, It will have to be probed back to the PCM connector in order to check the circuit.

 

I'll see if I can get those readings tomorrow. With ignition on but the engine not started, I read a full 12v between pin c and D. Ill see If it reads any continuity to ground. I would expect it to. I'll fool around with it and take the readings if I have time tomorrow. It would be nice if I had any small connectors to get a reliable connection between my multimeter and the pins on the connector so I can yank on the wire while getting a reading. Alligator clips might suffice.

 

if you have replaced the old O2 sensor you can just cut the wires from the old one and use the pigtail to do your testing.

 

Not sure who is still following at this point but I'll keep this updated in case it helps anyone else. The dealer said they tested all the wires and they tested good. They said they'd warranty the sensor one more time, and if the code throws again, it's definitely the pcm that's bad. They also said after replacing the sensor, they drove it a lot and went over bumps and the light still wouldn't come on. Milage in was 102606 and milage out was 102609, so i don't think they really thoroughly tested it.

On my 10 mile drive home, the light came back on. It will be going in tomorrow for the pcm replacement. I just have to make sure I have the tune to flash on the new one. Hopefully, this fixes all my problems. I'll try and get them to cover the pcm replacement under warranty since we had no issues until the second we drove off the lot after getting the transmission replaced, and there was definitely wiring harness damage due to the transmission replacement. Also we've had to pay a few hundred in a misdiagnosed o2 sensor replacement

 

thanks for the update, keep us posted on the PCM update

Neal

 

we're all following

It's good you're keeping your post updated, your experiences are valuable.

Intermittent faults can be notoriously difficult to trouble shoot, you'll only know for sure that you've found it over a period time, or if you nail it down with evidence.

Hopefully the PCM replacement works OK and solves the issue..

 

The dealer said they'd cover the cost of the pcm replacement. This was about 2 weeks ago. Tuesday, after it had sat for more than a week with nothing done on the lot, they called and said because of the supercharger, they cannot program the ecu. We called bs on that. They can program the ECU then flash the supercharger tune without issue. I can understand from a liability standpoint, but it's not like im telling them to drive the vehicle. All they have to do is program it, then flash the tune. They should be able to do it without starting the vehicle. Hell, I'm sure they have a way to bench program them. And anyway, they caused the screw up so they need to figure it out. We've crossed the liability line a year ago anyway.

On top of all this, they STILL didn't fix their wiring disaster under the truck. I told them not to put the ecu in until the wire is properly secured and not going to short on any metal.

It's still sitting there, and we've told them they need to figure it out. We've given them the tune and all the resources they need. They recommended we take it to our local Vengence Racing to get it programmed, which we will do if they can't get their act together. I even talked to the mechanic himself, who I can tell knows he screwed up. He wanted nothing to do with me.

I also talked to another service rep when I brought it in again. He said that it is common and their mechanics have pinched wires when doing 6l80s. Though uncommon on the hummers because of the extra room, it's still possible.

 

I'm not sure that the dealership tools Tech2 or GDS/VCI have any way to accept and program a third party tune. I know a Tech2 cannot - that can only program things as it comes from the factory. I'd assume that the newer GDS/VCI setup cannot either. You might have to let them install the new PCM, program it to the vehicle with the VIN then take it to some performance place that has HPTuners or EFILive to flash the calibration for the supercharger.

 

I have the tune and the device to flash the tune and I gave it to them to use. The only thing that needs done is the ecu programmed to the truck so the vins match and everything. I have no idea how ecu programming works. My assumption is they plug it into the vehicle and program it with a tech 2. I don't know if the vehicle has to be started or not. My assumption is no, but i could be wrong. Either way, the supercharger can be bypassed by zip tieing open the bypass valve. That would work well enough for an initial start. Then they just have to load the tune.

The problem is I don't have the tools to do the actual vin programming. I can't find any resources online on how to do this. Hell, if I can do it myself, I will.

 

For replacing the PCM they will need to use a Tech2 of GDS, connect it to a computer and set the VIN and any options that might be required. Vehicle is not running for that part. Once that is done then a security relearn is needed for it to be able to start. Once that is done two options -strap the bypass open, start it up and do a crank variation relearn OR first flash the SC tune, then start it and do the crank variation relearn.