Circuit Description
The fuel level sensor changes resistance based on fuel level. The powertrain control module (PCM) or the engine control module (ECM) monitors the signal circuit of the fuel level sensor in order to determine fuel level. When the fuel tank is full, the sensor resistance is high and the PCM/ECM senses a high signal voltage. When the fuel tank is empty, the sensor resistance is low and the PCM/ECM senses a low signal voltage. The PCM/ECM uses the signal circuit of the fuel level sensor in order to calculate the total remaining fuel percentage in the tank. The PCM/ECM sends the fuel level percent via a discrete input to the instrument panel cluster (IPC) in order to control the fuel gage.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0462 Fuel Level Sensor Circuit Low Voltage
Conditions for Running the DTC
The ignition is ON, with the engine ON.
Conditions for Setting the DTC
| • | The total resistance of the circuit is below 37 ohms. |
| • | The fuel level signal is 0 percent. |
| • | The above condition is present for greater than 10 seconds. |
Action Taken When the DTC Sets
The PCM/ECM records the operating conditions at the time the diagnostic fails. The PCM/ECM displays the failure information in the Failure Records on the scan tool.
Conditions for Clearing the DTC
| • | The DTC becomes history when the conditions for setting the DTC are no longer present. |
| • | The history DTC clears after 40 malfunction-free warm-up cycles. |
| • | The PCM/ECM receives the clear code command from the scan tool. |
Diagnostic Aids
| • | Use the Freeze Frame and/or Failure Records data in order to locate an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data may aid in determining the number of miles since the DTC set. The Fail Counter and Pass Counter can also aid in determining the number of ignition cycles that the diagnostic reported a pass and/or fail. Operate the vehicle within the same freeze frame conditions (RPM, engine load, vehicle speed, temperature, etc.). This will isolate when the DTC failed. |
| • | Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Instrument Cluster Schematics Connector End View Reference: Engine Controls Connector End Views in Engine Controls - 5.3L, Powertrain Control Module Connector End Views in Engine Controls 3.8L or Inline Harness Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Does the scan tool indicate that the Fuel Tank Level Remaining parameter is less than the specified value? | 4% | Go to Step 3 | Go to Diagnostic Aids |
Does the scan tool indicate that the Fuel Level parameter is greater than the specified value? | 98% | Go to Step 5 | Go to Step 4 | |
4 | Test the signal circuit of the fuel level sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 6 |
5 | Inspect for poor connections at the harness connector of the fuel level sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 7 |
6 | Inspect for poor connections at the harness connector of the PCM/ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 8 |
7 | Replace the fuel level sensor. Refer to Fuel Level Sensor Replacement in Engine Controls - 3.8L or Fuel Level Sensor Replacement in Engine Controls - 5.3L. Did you complete the replacement? | -- | Go to Step 9 | -- |
8 | Replace the PCM/ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 9 | -- |
9 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
