03+ cluster crashing PCM reflash

[RADustin]

In GMT-800, I have a P01 truck (2001) that is now P59 swapped with a 03 cluster. Everything is working except during a reflash of the PCM I have to unplug the gauges for it to work. The gauges will reflash with IPChammer fine. I tried using either 1 of 2 possible ignition feeds for the IPC, as the 2001 has two and the IPC only needs 1- didn't make a difference.

Can anyone think of what may be going on? I guess my next plan of action is to log the bus with the logger program during a reflash event. Using EFILive for the tuning tool, it just errors saying no communication. Same error I get when people have aftermarket radios.

Thanks

[antus]

Some devices through hardware fault or bad design wont silence when requested by the flash tool. Its likely your cluster is one such device. If thats the case you cant do anything about it, other than flash on the bench or disconnect the offending cluster.

[RADustin]

I tried a different cluster, another 2003 stock cluster. Same results.

The P59 trucks have a more integrated BCM, and my thought is this BCM is telling the IPC to hush while re-flashing. But I need to confirm that, and see if there is a work around like with the volt gauge.

[RADustin]

to follow up- its a shifty experience. sometimes it works, sometimes it doesn't. It has a higher chance to work if I reflash the pcm soon after turning the ignition on. If the ignition is on for a few minutes, it'll generally fail. But cycling key, or unplugged IPC will allow the reflash.

Due to it sort of working and finding strange workarounds, I haven't datalogged it or worked this any further.

[Phoenix]

I know that sometimes people have more success when they remove the Onstar and radio fuses.

[RADustin]

It's definitely the IPC. I tried all sorts of different combinations of pulling fuses. Only works reliably when IPC is dead or completely unplugged. Also truck doesn't have onstar.

There was never a problem before I swapped the IPC...very strange.

[antus]

Maybe its looking for a module thats not installed in your vehicle but was in the donor vehicle, and without it having initialised everything it thinks should be there it might not be able to go silent, or something like that. Something that doesnt trigger a CEL so you dont know its doing it.