P0462

P0462-FUEL LEVEL SENSOR 1 CIRCUIT LOW





For complete wiring diagrams refer to Diagrams/Electrical.


Theory of Operation

The fuel level rationality will set a fault for a fuel level reading that does not change over an accumulated mileage threshold to keep stuck high or stuck low fuel levels from disabling OBD monitors. If the vehicle is fitted with a saddle tank fuel system this feature includes diagnostics for both of the sending units and diagnostics for a siphon tube that has become disconnected or plugged. The power up test looks to see a large enough fuel level voltage change from the last key-off to the following engine run. The engine run test looks to see a fuel level voltage change over an accumulated mileage.

- When Monitored:

Ignition on and battery voltage above 10.4 volts.

- Set Condition:

The Fuel Level Sensor 1 input voltage is below the minimum acceptable value. One Trip Fault. Three good trips to turn off the MIL.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test


1. FUEL LEVEL SENSOR VOLTAGE BELOW 0.4 OF A VOLT


NOTE: Diagnose and repair any system voltage DTCs before continuing with this test.


NOTE: Diagnose and repair any communication DTCs before continuing with this test.

Start the engine and allow it to reach operating temperature.


WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

With the 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. FUEL LEVEL SENSOR

Turn the ignition off.

Disconnect the Fuel Pump Module harness connector.

Ignition on, engine not running.

With the scan tool, read the Fuel Level Sensor voltage.

Did the Fuel Level Sensor voltage change from below 0.4 of a volt to above 4.0 volts?

Yes

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

No

- Go To 3

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





Turn the ignition off.

Disconnect the C4 Cluster harness connector.

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 POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 4

4. (N4) FUEL LEVEL SIGNAL CIRCUIT OPEN





Measure the resistance of the (N4) Fuel Level Signal circuit from the Fuel Pump Module harness connector to the C4 Cluster 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 POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

5. INSTRUMENT CLUSTER

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

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 BODY VERIFICATION TEST-VER 1. Body Verification Test

No

- Replace and program the Instrument Cluster.
- Perform BODY VERIFICATION TEST-VER 1. Body Verification Test