P0461

Schematic:

CIRCUIT DESCRIPTION
The PCM uses a fuel level input in order to calculate the expected vapor pressures within the fuel system. These vapor pressures vary as the fuel level changes. The vapor pressure is critical in determining if the Evaporative Emission (EVAP) system is operating properly. The PCM also uses the fuel level in order to determine if the fuel level is too high or too low to be able to accurately detect an EVAP system malfunction.

CONDITIONS FOR RUNNING THE DTC
^ The ignition is ON.
^ The system voltage is between 11.0 volts and 16.0 volts.

CONDITIONS FOR SETTING THE DTC
Fuel level has not changed more than 1.6 percent in 193 km (120 miles).

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will record the operating conditions during the time which the diagnostic tails. This information will store in the Failure Records buffer.
^ A history DTC is stored.

CONDITIONS FOR CLEARING THE DTC
^ A history DTC clears after 40 consecutive warm up cycles without a fault.
^ The scan tool clears the DTC.

DIAGNOSTIC AIDS
^ Inspect for the following conditions that may cause intermittents:
- Poor electrical connections
- Rubbed through wire insulation
- A wire that is broken inside the wire insulation
^ Thoroughly inspect any circuitry that is suspected as causing the intermittent complaint. Inspect for the following conditions:
- Backed out terminals
- Improper mating
- Broken locks
- Improperly formed or damaged terminals
- Poor terminal to wire connections
^ Before replacing the PCM, inspect the PCM electrical connector terminals for the following conditions:
- Improper mating
- Broken locks
- Physical damage to the wiring harness

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
1. The Powertrain On-Board Diagnostic (OBD) System Check prompts you to complete some of the basic checks and to store the Freeze Frame and Failure Records data on the scan tool if applicable. This creates an electronic copy of the data captured when the malfunction occurred. The scan tool stores this data for later reference.
9. Replacement PCMs must be reprogrammed and the Crankshaft Position System Variation Procedure must be performed. Refer to the latest Techline information for programming procedures.