P0461

DTC P0461 FUEL LEVEL RATIONALITY




Circuit Description
The powertrain control module (PCM)/engine control module (ECM) uses the fuel level input from the Fuel Level Sensor to calculate expected vapor pressures within the fuel system. Vapor pressures vary as the fuel level changes. Vapor pressure is critical in determining if the evaporative (EVAP) emission system is operating properly. Fuel level is also used to determine if the fuel level is too high or too low to be able to accurately detect EVAP emission system faults. This Diagnostic Trouble Code (DTC) detects a stuck fuel level sender.

Conditions for Setting the DTC
- Raw fuel level sender output change is greater than 3 A/D counts (5%) within 200 km.

Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will not illuminate.
- The PCM/ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.
- 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.
- DTC(s) can be cleared by disconnecting the battery.
- Using a scan tool.

Diagnostic Aids
If DTC P0463 is also displayed, go to DTC P0463 first.
Inspect harness connectors for backed-out terminal, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal-to-wire connection.
Inspect the wiring harness for damage.
A stuck fuel level sensor may cause the DTC to set.
If DTC P0461 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set.
Resistance checks for the fuel level sensor:
- Empty=100 ohms or over.
- Half Full=about 32.5 ohms.
- Full=10 ohms or less.

Steps 1 To 12:

Test Description
The number(s) below refer to step(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.
2. Determine if fault is present. Reviews Freeze Frame data to determine when the DTC set. Always record this information.