Diagnostic Test

1) CHECK FOR DTC U0401-IMPLAUSIBLE DATA RECEIVED FROM ECM/PCM
NOTE: This DTC must be active for the results of this test to be valid.

Turn the ignition on.

With the scan tool, record and erase DTCs.

Cycle the ignition switch from off to on.

With the scan tool, read DTCs.

Does the scan tool display: U0401-IMPLAUSIBLE DATA RECEIVED FROM ECM/PCM?

Yes
1. Go to 2).
No
1. Refer to INTERMITTENT CONDITION diagnostic procedure.
2. Refer to ABS-INTERMITTENT CONDITION TEST .
2) CHECK IF FCM CAN BUS DTCS ARE PRESENT
With the scan tool, read FCM DTCs.

Are there any FCM CAN BUS DTCs present?

Yes
1. Refer to DIAGNOSIS AND TESTING and diagnose the appropriate symptom.
2. Perform ABS VERIFICATION TEST .
No
1. Go to 3).
3) CHECK IF ENGINE DTCS ARE PRESENT
With the scan tool, read Engine DTCs.

Are there any Engine DTCs present?

Yes
1. Refer to the appropriate Engine ELECTRICAL DIAGNOSTICS article and diagnose the appropriate symptom.
2. Perform ABS VERIFICATION TEST .
No
1. Using the schematics as a guide, check the Anti-Lock Brake Module pins, terminals, and connectors for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace the Anti-Lock Brake Module per the Service Information.
2. Perform ABS VERIFICATION TEST .