Circuit Description

Fuel level sensor is an important input to PCM for enhanced evaporative (EVAP) system diagnostic. Fuel level information is needed for PCM to know volume of fuel in tank. Fuel level affects rate of change in air pressure in EVAP system. Sending unit is a float in fuel tank which moves a wiper arm across a variable resister. Low fuel level causes high resistance in sending unit and this is recognized by PCM because circuit operates at a corresponding low voltage. When circuit is continuously open or has a high resistance connection, or there are 12 test failures within 80 test samples, DTC P0464 is stored.

When DTC sets, PCM illuminates MIL on second trip after fault was detected. PCM will store conditions present when DTC was set as freeze frame data in the FAILURE RECORDS data.

DTC can be cleared with scan tool, or by disconnecting battery voltage feed to PCM.