The powertrain control module (PCM) uses the 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 Emissions 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 EVAP system malfunction.

The fuel level has not changed more than 1.6% (4 counts) in 120 miles.

Whenever a DTC P0460 is set along with an EVAP System DTC, the EVAP DTC can not be considered valid until DTC P0460 is repaired and cleared.

The numbers below refer to the step numbers on the diagnostic table.

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the Freeze Frame Data and the Failure Records on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurs. Refer to this information on the scan tool later.

2. The fuel level sensor is diagnosed in Section 8C-1 of the service manual.

4. Repair verification is an important step in any diagnostic procedure. Comparing the fuel level readings before and after the repairs is a good way to determine if a repair has been successful.