Overview:
Fault Code 12 indicates an internal failure of the Transmission Controller.

Detection:
The Transmission Controller checks the program memory every time the key is turned on. If the Transmission Controller detects a failure within the program memory, it sets this fault code.

Fallback:
This fault causes an in-place fallback while moving and a failure during system initialization.

Possible Causes:
1) Improper configuration software
2) Transmission controller

Shop Talk:
Key on. If the fault is present, the system should automatically detect the problem and set the code. If the fault is not present at key on, operate the vehicle and attempt to duplicate the driving conditions that triggered the fault code. Possible triggers include heat and vibration.