U1403

U1403-IMPLAUSIBLE FUEL LEVEL SIGNAL





For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams.

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.

- When Monitored:
Ignition on.

- Set Condition:
The fuel level message the PCM is receiving is implausible. The circuit is continuously monitored. One trip fault.





WARNING: On vehicles equipped with the high voltage system, you must thoroughly read and follow all High Voltage Safety procedures. In addition, before performing any diagnostic or service procedure near a high voltage component, you must perform the High Voltage Power Down. Failure to follow these instructions may result in possible serious or fatal injury

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. ACTIVE DTC
1. Ignition on, engine not running.
2. With a scan tool, select View DTCs.

Is the DTC Active at this time?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.

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

Are any CAN B or CAN C Hardware related DTCs active at this time?

Yes

- Testing and Inspection Perform the appropriate diagnostic procedure.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 3

3. (N4) FUEL LEVEL SIGNAL CIRCUIT OPEN




1. Turn the ignition off.
2. Disconnect the Fuel Pump Module harness connector.
3. Disconnect the C2 Cluster harness connectors.
4. Measure the resistance of the (N4) Fuel Level Signal circuit from the Fuel Pump Module harness connector to the C2 Cluster harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 4

No

- Repair the open in the (N4) Fuel Level Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

4. (N4) FUEL LEVEL SIGNAL CIRCUIT SHORTED TO GROUND




1. Measure the resistance between ground and the (N4) Fuel Level Signal circuit in the Fuel Pump Module harness connector.

Is the resistance below 100 Ohms?

Yes

- Repair the short to ground in the (N4) Fuel Level Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 5

5. (N5) FUEL LEVEL SENSOR RETURN CIRCUIT OPEN




1. Measure the resistance of the (N5) Fuel Level Sensor Return circuit from the Fuel Pump Module harness connector to the C2 Cluster harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 6

No

- Repair the open in the (N5) Fuel Level Sensor Return circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

6. (N4) FUEL LEVEL SIGNAL CIRCUIT SHORTED TO THE (N5) FUEL LEVEL SENSOR RETURN CIRCUIT




1. Measure the resistance between the (N4) Fuel Level Signal circuit and the (N5) Fuel Level Sensor Return circuit in the Fuel Pump Module harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Repair the short between the (N5) Fuel Level Sensor Return circuit and the (N4) Fuel Level Signal circuit.
- Perform the BODY VERIFICATION TEST Body Verification Test.

No

- Go To 7

7. POWERTRAIN CONTROL MODULE (PCM)

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

1. Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Replace and program the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.