Powertrain Control Module (PCM)

P0462-FUEL LEVEL SENSOR 1 CIRCUIT LOW




For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation

The Fuel Level Sensor is attached to the side of the Fuel Pump Module. The sending unit consists of a float, an arm and a variable resistor track (card). The fuel transfer pump is also attached to the Fuel Pump Module. A constant 5-Volt signal is supplied to the resistor track of the fuel gauge sending unit. The resistor track is a variable resistor used to vary the voltage signal depending on fuel tank float position. As fuel level increases, the float and arm move up, which decreases voltage. As fuel level decreases, the float and arm move down which increases voltage. When the fuel tank level is measured below 15%, the following fuel system monitors are shut off: P0191 (Fuel Pressure Idle Diagnostic portion of it), and DTCs P0300, P0301, P0302, P0303, P0304, P0305, P0306. The TIPM will illuminate the MIL lamp immediately after this diagnostic runs and fails. The TIPM will turn off the MIL lamp after the diagnostic runs and passes in four consecutive drive cycles.

- When Monitored:
Ignition on and battery voltage above 10.4 Volts.

- Set Condition:
The signal voltage from the sensor falls below a calibrated value for a calibrated amount of time.





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

1. ACTIVE DTC
1. Ignition on, engine not running.
2. With the scan tool check for active DTCs.

Is the DTC active?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION - 6.7L diagnostic procedure. Intermittent Condition Test

2. CHECK THE FUEL LEVEL SENSOR
1. Ignition on, engine not running.
2. Disconnect the Fuel Pump Module harness connector.
3. With the scan tool check for DTC P0463.

Did DTC P0463 set after unplugging sensor?

Yes

- Replace the Fuel Level Sensor.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 3

3. CHECK THE (N4) FUEL LEVEL SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND




1. Turn ignition off.
2. Disconnect the TIPM C7 harness connector.
3. Measure the resistance between ground and the (N4) Fuel Level Sensor Signal circuit at the TIPM C7 harness connector.

Is the resistance below 10k Ohms?

Yes

- Repair the (N4) Fuel Level Sensor Signal circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 4

4. CHECK FOR THE FUEL LEVEL SENSOR SIGNAL CIRCUIT SHORTED TO THE (G109) FUEL LEVEL SENSOR RETURN CIRCUIT




1. Measure the resistance between the (N4) Fuel Level Sensor Signal circuit and the (G109) Fuel Level Sensor Return circuit at the TIPM C7 harness connector.

Is the resistance below 10k Ohms?

Yes

- Repair the short between the (N4) Fuel Level Sensor Signal circuit and the (G109) Fuel Level Sensor Return circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Replace the Totally Integrated Power Module (TIPM).
- Perform the BODY VERIFICATION TEST. Body Verification Test.