Originally Posted by Faslane

I have a 09 base automatic 19k miles. known the car its whole life, no accidents or issues, It is my wife's 2nd car and she does not drive it much but it gets started and moved around the shop weekly to move cars around make some room or to get another car out. I started having the no start situation where you push start and the gauges sweep then blank with only the check engine light symbol showing and no start. I googled and learned a lot, I found and cleaned all the grounds, battery checked and replaced checked all the connection while battery out and eve took the tray out to check cables, blue connectors at BCM, all the easy free things to check, I came to my opinion of replacing the BCM, I went to the dealership and bought a brand new BCM. I have a Tech 2 and a membership at tis web and also have Tech 2 Win using my MDI 2 as pass through. Got it home installed set up BCM, Crank relearn, unlocked radio ect. started great. All went great except I could not calibrate the brake switch, I tried everything, the brake lights were on all the time as well, It also said the service warnings on dash for suspension and traction systems, I have read tons of forum threads about this issue and had a good feeling it was a connector somewhere, cleaned and checked all connectors or connections that are usually the culprit, no change. I then ordered a brake switch off ebay even tho I had a feeling it was not the issue from all the information from all the threads I have read. I installed the brake switch from ebay turned ignition on fired up the tech 2 went to calibrate and no deal, same as before. I went another month or so reading and learning and nothing changed the situation, I even tried through tis web with the mdi 2 an no dice. One day I went to advance auto parts to get something for another car and thought what the heck ordered another brake switch for her vette. It was the BWD brand, unhooked the negative side of the battery installed that brake switch I powered up turned key on, perfect, showed hit brake to start on dash, pushed the brake started the car, have brake light working correctly no service on dash, was able to turn traction control on and off it was perfect, I was so happy, I went through with the tech 2 and every module was 0 codes! I started putting everything back together and left it running while doing so and after 10 minutes BING traction control light came on and 2 seconds later the check engine light came up and the service stability reading on the dash, the brake lights still worked perfect. I fired up the tech 2 right then and I had 5 codes in the ecm, had 3 in the BCM, had 3 in the EBCM and 1 in the TCM. I cleared everything thinking it may been a clitch or something from monkeying around with things. They all cleared and started the car back and same issues they all came back rather quickly this time like in 5 seconds. I cleared one more time, I was going to right everything down from each module to make this post, and the codes came back as before the same exact codes in each module as before, I will list them bellow any help would be appreciated I have a connector or module dead somewhere IMO I would like and need some guidance any way thanks in advance. The brake lights are still working correctly as well.
Lane

ECM
P150C TCM engine speed request circuit
P0700 TCM request mil illumination
U0121 lost comm. with ABS
U0101 lost comm. with TCM
P2544 Transmission torque request circuit

BCM
U2108 lost comm. with ABS and traction control
U2106 lost comm. with TCM (I Think)?

EBCM
U0100 lost comm. with ECM/PCM
U0101 lost comm. with TCM
U0073 control module comm. bus off

TCM
U0073 lost comm. bus A off

Driver Door Module
U1017 lost comm. with ECM

ESCM No comm. ? suspension control may be in EBCM ??
EFCM No comm. ????

Thanks again
Lane