P0462
DTC P0462 (3.6L LY7)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P0462
- Fuel Level Sensor 1 Circuit Low Voltage
Diagnostic Fault Information
Circuit/System Description
The primary fuel level sender and the secondary fuel level sender changes resistance based on fuel level. The engine control module (ECM) monitors the signal circuits of the primary fuel level sender and the secondary fuel level sender in order to determine the fuel level. When the fuel tank is full, the resistances of both fuel level senders are low and the ECM senses a low signal voltage on both the signal circuits of the primary fuel level sender and the secondary fuel level sender. When the fuel tanks are empty, the resistances of the fuel level senders are high and the ECM senses a high signal voltage. The ECM uses the signal circuits of the primary fuel level sender and the secondary fuel level sender in order to calculate the percentage of remaining fuel in the tank. The ECM sends the fuel level percentage via serial data circuit to the instrument cluster in order to control the fuel gauge.
Conditions for Running the DTC
* The engine is running.
* The system voltage is between 10-18 volts.
Conditions for Setting the DTC
* The primary fuel level sender output is less than 0.25 volt.
* The above condition is present for about 60 seconds.
Action Taken When the DTC Sets
* The fuel gauge defaults to empty.
* The driver information center (DIC) displays the FUEL LEVEL LOW message.
* The ECM records the operating conditions at the time that the diagnostic test fails. The 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.
Reference Information
Schematic Reference
Instrument Cluster Schematics (Instrument Cluster Schematics)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Fuel Gauge Description and Operation (Fuel Gauge)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
Ignition ON, observe the scan tool Fuel Level Sensor parameter. The reading should be between 0.9 - 2.5 volts.
Circuit/System Testing
Note: If equipped, the following tests can be performed at an inline connector. See schematics for the corresponding terminals to test at.
1. Ignition OFF, disconnect the harness connector at the primary fuel level sensor.
2. Ignition ON, verify that the scan tool Fuel Level Sensor Left Tank parameter is greater than 4.5 volts.
• If less than the specified range, test the primary signal circuit terminal A for a short to ground. If the circuit tests normal, replace the ECM.
3. If all circuits test normal, perform the fuel level sensor component test before replacing the primary fuel level sensor.
Component Testing
1. Ignition OFF, remove the primary fuel level sender.
2. While sweeping the primary fuel level sensor through its full range of motion, test for a minimum value less than 41 ohms and a maximum value greater than 119 ohms between signal terminal A and the low reference terminal D.
• If not within the specified range, replace the primary fuel level sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Primary Fuel Level Sensor Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for the ECM replacement, setup, and programming