Checking The Lock-Up Function

If Transmission control module (TCM) receives information from Brake control module (BCM) that a wheel sensor is off, then Transmission control module (TCM) turns off the lock-up function during engine braking. hen the Lock-up function will be constantly open and the engine receives idle rpm during engine braking.

Fault cause 

• Look for the cause of the fault in the brake control module (BCM).

Fault symptom 

• Automatic transmission/Lockup does not work