U1403

U1403-IMPLAUSIBLE FUEL LEVEL SIGNAL

U1403-Implausible Fuel Level Signal:

WHEN MONITORED
Ignition on.

SET CONDITION
The fuel level message that 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 receives a fuel level signal over CAN B from the Cluster Module. Once the message is received from the FCM, it passages the fuel level message via CAN C to the PCM.

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 DTCs.

Q: Is the DTC active at this time?

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

2. U0019-NO COMMUNICATION ON THE CAN B BUS CIRCUIT ALSO ACTIVE

With a scan tool check for DTCs in the FCM.

Q: Is the U0019-NO COMMUNICATION ON THE CAN B BUS CIRCUIT active at this time?

YES: Refer to Body Control Systems for the U0019-NO COMMUNICATION ON THE CAN B BUS CIRCUIT diagnostic procedures. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Replace and program the Powertrain Control Module. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test