U1403

U1403-IMPLAUSIBLE FUEL LEVEL SIGNAL

U1403-Implausible Fuel Level Signal:

WHEN MONITORED
Ignition on.

SET CONDITION
The fuel level message the PCM is receiving is implausible. The circuit is continuously monitored.

POSSIBLE CAUSES
- CAN B Open or shorted
- Cluster module
- Front control module
- PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Theory of Operation
The Front Control Module isn't receiving a fuel level signal over CAN B from the Cluster Module. The FCM has to send the PCM a fuel level signal over CAN C. The signal the FCM sends over CAN C is implausible.

DIAGNOSTIC TEST

1. ACTIVE DTC
Ignition on, engine not running.
With a scan tool read DTCs.

Q: Is the DTC active at this time?

YES: Go To 2
NO: Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

2. CAN B BUS HARDWARE DTCS ALSO ACTIVE
With a scan tool check for DTCs in the FCM.

Q: Are any CAN B Hardware related DTCs active at this time?

YES: Perform BODY VERIFICATION TEST VER 1.
NO: Replace and program the Powertrain Control Module per Service Information. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test