Diagnostic Test

VERIFY DTC IS ACTIVE
NOTE: Ensure the IOD fuse is installed and battery voltage is between 10 and 16 volts before proceeding.
1. With the scan tool, read active DTCs.
Q: Is this DTC active?

Yes :
- Go To 2
No :
- Refer to *STORED LOST COMMUNICATION DTCS .
CHECK FOR ANY OF THE FOLLOWING ACTIVE DTCS
1. With the scan tool, read all active DTCs from all modules.
NOTE: Check for FCM configuration, CAN B or C hardware electrical, VIN Missing/Mismatch, battery or ignition related DTCs.

Q: Does the scan tool display any active DTCs to the conditions listed above?

Yes :
- Diagnose and repair the DTC. Refer to appropriate DTC.
No :
- Go To 3
VERIFY THAT THE ECM/PCM IS ACTIVE ON THE BUS
1. Turn the ignition on.
2. With the scan tool, select System select.
3. Verify that the ECM/PCM is active on the bus (not grayed out).
Q: Is the ECM/PCM active on the bus?

Yes :
- Go To 4
No :
- Refer to the appropriate No Response test procedure in this article.
CHECK FOR ADDITIONAL COMMUNICATION RELATED DTCS
1. With the scan tool, select Special function.
2. Select all DTCs.
Q: Is there more than one module with active DTCs "Logged Against" the ECM/PCM?

Yes :
- Replace/update the ECM/PCM in accordance with the service information.
- Perform the appropriate VERIFICATION TEST.
No :
- Replace/update the module that set this DTC in accordance with the service information.
- Perform the appropriate VERIFICATION TEST.