Diagnostic Test

1) ACTIVE DTC
NOTE: Diagnose all CAN B and C communication failures before continuing.

Ignition on, engine not running.

With a scan tool, read ACC DTCs.

Is the DTC active at this time?

Yes
1. Go To 2).
No
1. The conditions that caused this code to set are not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors, pay particulate attention the CAN circuits.
2. Perform ACC MODULE VERIFICATION TEST .
2) ECM/PCM ACTIVE ON THE CAN C BUS
With the scan tool, select ECU View.

Verify that the ECM/PCM active on the bus.

Is the ECM/PCM active on the bus?

Yes
1. Go To 3).
No
1. (Refer to ELECTRONIC CONTROL MODULES - ELECTRICAL DIAGNOSTICS ) article for NO RESPONSE diagnostic procedures.
3) DTCS STORED OR ACTIVE IN THE ECM/PCM
Are any DTCs active or stored in the PCM Module?

Yes
1. Refer to the appropriate Engine ELECTRICAL DIAGNOSTICS article and perform the diagnostics for the DTCs.
No
1. Go to 4).
4) ACTIVE DTCS IN THE FCM
With the scan tool, select ECU View and select FCM.

With the scan tool, read active DTCs.

Are any Communication DTCs active in the FCM relating to the PCM?

Yes
1. (Refer to ELECTRONIC CONTROL MODULES - ELECTRICAL DIAGNOSTICS ) article for the diagnostic procedures.
No
1. Replace and program the ACC Module in accordance with the Service Information.
2. Perform ACC MODULE VERIFICATION TEST .