DTC Descriptor
DTC P0462: Fuel Level Sensor Circuit Low Voltage
Circuit Description
The fuel level sensor changes resistance based on fuel level. The fuel level sensor has a signal circuit and a ground circuit. The engine control module (ECM) applies 5 volts on the signal circuit to the sensor. The ECM monitors the changes in this
voltage caused by changes in the resistance of the sensor in order to determine fuel level.
When the fuel tank is full, the sensor resistance is low, and the ECM signal voltage is high. When the fuel tank is empty, the sensor resistance is high, and the signal voltage is low.
The ECM uses inputs from the fuel level sensor in order to calculate the total fuel percentage remaining in the fuel tank. The ECM uses the fuel level information for the evaporative emission (EVAP) and misfire diagnostics. The fuel level information is
sent to the instrument panel cluster (IPC).
If the ECM detects a signal voltage lower than the operating range of the sensor, this DTC sets.
Conditions for Running the DTC
| • | DTC P0462 runs continuously once the above conditions are met. |
Conditions for Setting the DTC
| • | The ECM detects that fuel level signal voltage is less than 0.25 volts. |
| • | The above condition is present for more than 10 seconds. |
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records. |
| • | The fuel gage defaults to empty. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the MIL after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a 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.
Reference Information
Schematic Reference
Instrument Cluster Schematics
Connector End View Reference
Instrument Panel, Gages, and Console Connector End Views
Electrical Information Reference
Circuit/System Verification
- Ignition ON, observe the scan tool Fuel Level Sensor voltage parameter. The reading should be between 0.25-4.25 volts.
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the fuel level sensor through the access panel under the rear seat.
- Ignition OFF, test for less than 10 ohms of resistance between the low reference circuit terminal and ground.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the control module. |
- Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal and ground.
| ⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the control module. |
| ⇒ | If greater than the specified range, test the
signal circuit for a short to voltage. If the circuit tests normal, replace the control module. |
- If all circuit/connections test normal, test or replace the fuel level sensor.
Repair Instructions
