I am experiencing an issue with StabilitTrak that I have never seen before, hopefully someone can shed some light on this.
The car is a 2014 Z28, E38 ECU, LS7 engine, had cam and headers when I got it. I did some very basic tune changes and the car ran night and day better with basic idle adjustments. I drove the car for about 3000 miles with no SES light or any StabiliTrak issues. One random day in stop and go traffic the service stabilitrak light came on while sitting still. As soon as i started rolling the light went off. This kept up for a few cycles then I got a SES light and the service stabilitrak light stayed on.
Got home and read DTCs, only DTC was P0106. I cleared the code, drove and all seemed well. As soon as i killed the car and restarted it, P0106 came back. It may be a coincidence, but this was the first cool day we had since I got the car. We have had several 90+ days since and I tested this and still had issues.
Now, to the real issue. I know how to completely disable this P0106 test, but it appears to also disable traction control and stability management when I do so. I do not get a "Service StabiliTrak" light, but traction control does not function at all when I disable the P0101, P0106, P0121 using the coolant temp parameters. I dont have a way to test this because if i enable the P0106 test, I immediately get P0106 and that disables StabiliTrak but also generates a "Service StabiliTrak" Light. It is very possible that it is a hardware or wiring issue but I have tested all grounds to ECU and body control unit. MAP reading was around 65KPA at idle, Im not sure what range the P0106 is looking for, but idle vacuum has been the same from day one and this is a new issue.
My questions are:
1) I also have repeatedly got lots of communication DTCs that dont even show up with HP-Tuners, I believe you need a Tech 2 or equivalent to read them because that is what I borrowed. These all seem to be set any time I flash the ECU using HP. Is this a common issue?
2) The gen3 ECUs had tables to set the MIN and MAX acceptable values for P0106 test results. This appears to be gone on the gen4 stuff. Is there something I am missing? Can we still change the acceptable MAP range for P0106?
3) Has anyone seen similar issues with ZL1 or Z28? as far as i know, these two models are the only ones that have the more advanced StabiliTrak system.
4) Does anyone know if the body control unit waits on a successful P0101, P0106, and P0121 before enabling traction control and stability management? If so, disabling these tests could cause this?
Thanks, I would appreciate any input on this issue.