Diagnostic Test

CHECK FOR AN ACTIVE DTC

NOTE:

Make sure the battery is fully charged before proceeding.

Turn the ignition on.
With the scan tool, read the active DTCs.
Does the scan tool display: U1733-87-LOST COMMUNICATION WITH CTM?

Yes
- Perform the U1733-87-Lost Communication with CTM diagnostic procedure. Refer to BODY CONTROL MODULE (BCM) - DIAGNOSTIC CODE INDEX - 500 - EXCEPT ELECTRIC .
No
- Perform the Stored Lost Communication DTCs diagnostic procedure. Refer to STORED LOST COMMUNICATION DTCS .