P0464

Circuit Description
The Engine Control Module (ECM) uses the signal from the fuel level sensor to calculate expected vapor pressure within the fuel system. Vapor pressure varies as the fuel level changes. Vapor pressure is critical in determining if the Evaporative Emission (EVAP) system is operating properly. The fuel level signal is also used to determine if the fuel level is too high or too low to be able to accurately detect EVAP system faults. This Diagnostic Trouble Code (DTC) detects a fuel level sensor that sends out a noisy signal.

Conditions for Setting the DTC
- The change in the fuel level sensor output is greater than 10 counts (0.2 volts) per diagnostic cycle.
- Intake Air Temperature (IAT) is greater than -10 °C (14 °F).
- Change in the Throttle Position Sensor (TPS) is less than 2%.
- Change in the Manifold Absolute Pressure (MAP) is less than 11 kPa.
- Change in engine speed is less than 100 rpm.
- Vehicle speed is less than 5 kph (3 mph).
- Stabilization timer is greater than 5 seconds.

Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will not illuminate.
- A history DTC is stored.

Conditions for Clearing the MIL/DTC
- A history DTC will clear after 40 consecutive warm-up cycles without a fault.
- The DTC(s) can be cleared by using the scan tool.

Diagnostic Aids
Resistance checks for the fuel level sensor:
- Empty = 280 ohms or more.
- Half full = about 90 ohms.
- Full = 38 ohms or less.

Steps 1 - 6:

Steps 7 - 10:

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
1. The On-Board Diagnostic (OBD II) System Check prompts the technician to complete some basic checks and store the Freeze Frame and Failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.
7. The replacement ECM must be reprogrammed. Refer to the latest Techline procedure for the ECM reprogramming.