My transmission went out in my 2010 suburban around thanksgiving, we had replaced the tranny a year ago so it was under warranty. The shop that put in the new transmission called me, I picked up the vehicle and noticed it was shifting more like it was in tow mode and at regular shift intervals. I drop the gear shifter down into the manual shift mode, and on the instrument cluster nothing changed, it acted as though it was still in drive. I tried hitting the tow mode button, and nothing happened. I took it back to the shop, they ran all the wire and ran diagnostics again and said their best guess was that it was a BCM (they said it was also throwing code P0826). I took it back I installed a new shifter, because I had seen where some of the wires on other peoples gear shifters had broken and mine were getting close. That did not fix it. I ordered a new BCM pre-programmed and installed it today, and still it’s not working. I’m at a loss, it almost feels like to me the transmission was programmed faulty, but the shop wouldn’t even listen to that suggestion. Has anybody ever experienced anything like this? Could a faulty connection into the transmission because in this problem? Any suggestions? I’d rate myself a novice when it comes to mechanicing.

Also I do know that these features were working before I took the vehicle to them. Because I have been using the manual mode to shift since the transmission was going out.

 

|P0826 CHEVROLET code possible causes

• Check other engine related codes first
• Faulty Engine Control Module (ECM)
• Engine Control Module harness is open or shorted
• Engine Control Module circuit poor electrical connection
• Faulty Transmission Control Module (TCM)

|What is P0826 CHEVROLET code meaning?

The Automatic Transmission Control Module (TCM) receives transmission-related information from the Engine Control Module (ECM) via serial data. When the ECM receives invalid transmission-related information, it notifies the TCM. The TCM then sets the appropriate Diagnostic Trouble Code (DTC).

 

Unfortunately , your trans shop either is not equipped to troubleshoot this problem or doesn't want to.