Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.

Observe the 4WD Signal in the ECM Data List. The 4WD signal should display Enabled when you shift into 4WD and Disabled when you shift into 2WD.
- If the scan tool display does not match the transfer case range switch state, repair the transfer case system refer to Diagnostic Starting Point - Transfer Case for BW 4485-NR3 or Diagnostic Starting Point - Transfer Case for MP 3023/3024-NQH.
- If the scan tool matches the transfer case range switch state, continue with testing.
Program the HPCM with the latest software version and retest for DTCs.
- If the DTC resets, replace the HPCM.