* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P0463
- Fuel Level Sensor 1 High Voltage
Diagnostic Fault Information
Circuit/System Description
The fuel level sensor changes resistance in response to the fuel level. The engine control module (ECM) monitors the signal circuit of the fuel level
sensor and the type of fuel in order to determine the fuel level. For regular unleaded fuel the ECM monitors a constant signal. When the vehicle has
approximately 20% or greater ethanol for E85 fuel applications, the ECM controls a pulse cycle signal where it monitors the signal and calculates
the fuel level percentage only during the on pulse of approximately 100 ms.
When the fuel tank is full, the sensor resistance is low and the ECM senses a low signal voltage. When the fuel tank is empty, the sensor resistance
is high and the ECM senses a high signal voltage. The ECM uses the signal circuit of the fuel level sensor in order to calculate the percentage of
remaining fuel in the tank. The ECM sends the fuel level percentage via the serial data circuit to the instrument cluster in order to control the fuel
gauge.
Conditions for Running the DTC
* The ignition is ON, with the engine running.
* The system voltage is between 11-18 V.
Conditions for Setting the DTC
* The sensor output is greater than 3.5 V.
* The above condition is present for greater than 30 seconds.
Action Taken When the DTC Sets
* The fuel gauge defaults to empty.
* The low fuel indicator illuminates.
* 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.
Diagnostic Aids
A defective fuel level sensor most likely will not set DTC P0463. The sensor has a 500 ohm default resistor that will prevent it from meeting the
code setting criteria of this DTC. Look for problems in the wiring and in the inline and harness connectors at the sensor and ECM.
Reference Information
Schematic Reference
Instrument Cluster Schematics (See: Diagrams/Electrical Diagrams/Instrument Panel, Gauges and Warning Indicators/System Diagram/Instrument
Cluster Schematics)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Instrument Cluster Description and Operation (See: Instrument Panel, Gauges and Warning Indicators/Description and Operation/Instrument
Cluster)
Electrical Information Reference
