Deserttaco

iTrader: (1)

About 10 years ago I purchased an 06 GTO as a donor for my 70 Chevelle project. After I drug the car home, I fixed some wiring and was able to get the car started. I disassembled the car and sold off a bunch of it. I kept the Engine, Transmission, Bumper to bumper wiring harness, BCM, PIM, Steering Column, Pedals, and just about everything you could use in a swap. I also have the original key and FOB that came with the GTO, it unlocks the car so the battery is good). I had a security light on the cluster, so I did the PIM relearn procedure, and now the security light is off, but I still get no crank, and no start, No communication..

The car Chevelle project was put on a back burner for a while, and over the last 2 years or so I've gotten back into it. This weekend, I was hoping to start the car for the first time, and ran into some issues. I disconnected and removed the ABS, (and all of the wiring that went with it...) I reconnected the GM HS LAN so that So that circuit used to be PCM->EBCM->PIM->DLC (there are two wires that are a twisted pair for this circuit). Now it is connected PCM->PIM-DLC. The car is a manual transmission so there is no TCM in the circuit. After a bunch of troubleshooting I figured I'd plug in my ELM327 and Torque Pro to see what was going on, and I have no communication to the PCM. I checked all of the connections in the DLC, (+12, Both Grounds, both the HS LAN+ and HS LAN-, and even the UART from the BCM). Measured the power, and it's +12.48 (engine off), Grounds are ~2.0 Ohms (respect to the battery negative). I can see some data on the LAN and UART pins (voltage fluctuates ~2.5V +/- .5V or so... When I plug in the ELM, the phone connects to the Bluetooth adapter, but there appears to be no communication with the PCM...

I'm wondering if this PCM is bricked? It's never been hooked up to, never tuned, and basically stock. The first time I powered it up yesterday, I was missing the HS LAN +/-, but I got them hooked up today. I tried to jumper out the PIM with the HSLAN wires, and the signal was basically 2.5V solid. No fluctuations, and there was still no communication with the PCM.

Any next steps? suggestions?

Jontall

It still needs the BCM to operate and I hope that you have it... This will help:
https://www.dropbox.com/sh/bf4xvfch6...a/Uploads?dl=0

Deserttaco

iTrader: (1)

Thanks for the help! I'll scour these today. I have the factory manuals, and have been scouring them for a few days, but it's really nice to have the whole circuits in one place... I do have the BCM and the PIM from the original car as well as the original key from the GTO. If I select the unlock button on the key fob, the lights on the car flash and the security light turns off. When I turn the key, I hear relays clicking when I transition from off to accy, accy to on, and on to start. I think today, I'm going to try to get my hands on another OBDII scanner and just make sure that I'm not chasing my tail.

Jontall

You really need a Tech II with this setup... It sounds like something is not linked: ECM> PIM> BCM> Fob. E40 ECM is very hard to brick but easy to unlink and with a Tech II you can relink everything.

Deserttaco

iTrader: (1)

Found a guy locally that has a tech II that is willing to come take a look on Sunday...

Deserttaco

iTrader: (1)

Just to follow up, When I removed the ABS computer, I opened up the HS, I had to reconnect them, so I used the 06 GTO FSM to get all of the right wires connected. As it turns out the Helms manual has an error in it (at least when compared to the wiring harness I have). According to the schematic, C1 pin1 should be Tan/Black... But in my connector C1P1 is Tan... C1Pin2 should be Tan, but in my connector C1P2 is Tan/Black. So If I hooked up stuff according to the color codes, I crossed these two wires. So I de-pinned the connections I made at C206 (when I removed the EBCM). Volia! Communications to the ECM...


Now is when the fun came... I read the codes and had: P0449 (EVAP), P0532 (AC Refrigerant), P0601 (Checksum Error), P0632 (Theft Deterrent Fuel Disable), and U0121 (lost communication with ABS). The two I was concerned about was the P0601, and the P0632. I tried to read the ECM, but got an error from HPTuners. So I sent them the file, their tech support sent it back about 2 hours later and said that it was fixed now. I loaded the tune, and still had the same problems. I found a GM Tech with a Tech 2 that said he could help me re-write the ECM to a stock calibration file to see if that would get rid of the fault. As it turns out (after a few hours of messing with it) I didn't write the tune correctly. I selected Write Vehicle, instead of Write Entire... After I selected Write entire, the P0601 disappeared. I disabled VATS1 and VATS2, and the car cranked. I removed the spark plugs and cranked it for about 45 seconds to make sure I had oil pressure (~30 PSI when cranking with no plugs), Reinstalled the plugs, put about 2 gallons of fuel in the tank and after about 30 seconds of cranking the car came to life...

Jontall

That's great news... Be sure to check/clean all the ground wires because they cause problems too.