FixVault

Possible Causes

Possible Causes 
ENGINE BRAKE DTCS PRESENT
WIN DTCS PRESENT
(K321) BTSI CONTROL CIRCUIT SHORTED TO VOLTAGE
SHIFTER LEVER ASSEMBLY

Always perform the NAG1 Pre-Diagnostic Troubleshooting procedure before proceeding. Refer to  DTC-Based Diagnostics/MODULE, Transmission Control (TCM) - Standard Procedure  .