U1403

U1403-IMPLAUSIBLE FUEL LEVEL SIGNAL RECEIVED





For a complete wiring diagram Refer to Diagrams/Electrical.


- When Monitored:
Ignition on.

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







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview.

Theory of Operation


The Totally Integrated Power Module isn't receiving a fuel volume signal from the Fuel Level Sensor. The PCM received the Fuel Level signal from the TIPM over the CAN C Bus circuit. The signal the TIPM is sending over CAN C is implausible.


Diagnostic Test


1. ACTIVE DTC
Ignition on, engine not running.
With a scan tool, select View DTCs.
Is the DTC Active at this time?

Yes


- Go To 2


No


- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition




2. CAN C HARDWARE DTCS ALSO ACTIVE
With a scan tool check for DTCs in the TIPM.
Are any CAN C Hardware related DTCs active at this time?

Yes


- Diagnose and repair the DTC(s).
- Perform the appropriate VERIFICATION TEST.Body Verification Test


No


- Go To 3




3. FUEL LEVEL SENSOR




Turn the ignition off.
Disconnect the Fuel Pump Module harness connector.
Ignition on, engine not running.
Using a fused jumper wire, jump the (K900) Sensor Ground circuit to the (N4) Fuel Level Sensor No.1 Signal circuit in the Fuel Pump Motor harness connector.
Did the Fuel gauge level change from empty to full?

Yes


- Replace the Fuel Level Sensor.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test


No


- Go To 4




4. (N4) FUEL LEVEL SIGNAL CIRCUIT OPEN




Turn the ignition off.
Disconnect the C7 TIPM harness connector.
Measure the resistance of the (N4) Fuel Level Signal circuit from the Fuel Pump Module harness connector to the C7 TIPM harness connector.
Is the resistance below 5.0 ohms?

Yes


- Go To 5


No


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




5. (N4) FUEL LEVEL SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT




Measure the resistance between the (N4) Fuel Level Signal circuit and the (K900) Sensor Ground circuit from the Fuel Pump Module harness connector.
Is the resistance below 5.0 ohms?

Yes


- Repair the short between the (K900) Sensor Ground circuit and the (N4) Fuel Level Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test


No


- Go To 6




6. (K900) SENSOR GROUND CIRCUIT OPEN




Disconnect the C2 PCM harness connector.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (K900) Sensor Ground circuit from the Fuel Pump Module harness connector to the TIPM harness connector.
Is the resistance below 5.0 ohms?

Yes


- Go To 7


No


- Repair the open in the (K900) Sensor Ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test




7. POWERTRAIN CONTROL MODULE (PCM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connector at the Powertrain Control Module (PCM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Powertrain Control Module connectors.
Refer to any Technical Service Bulletins that may apply.
Were there any problems found?

Yes


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


No


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