Tests AC

PINPOINT TEST AC: THE CHECK FUEL CAP INDICATOR IS NEVER/ALWAYS ON

Test AC1-AC3:

Test AC4:

Normal Operation
The powertrain control module (PCM) monitors the fuel tank evaporative system for significant leaks that occur following refueling of the vehicle. If a fuel tank pressure change greater than a minus 23.7 kPa (7 in Hg) of vacuum within 30 seconds after refueling has occurred, or there is excessive purge (fuel vapor) flow greater than 454 g (0.06 lb) per minute, the PCM will set DTC P0457 and send a message to the instrument cluster over the standard corporate protocol (SCP) communication network, circuits 4-EG8 (GY/VT) and 5-EG8 (BU/WH), to turn on the check fuel cap indicator.

Possible Causes
- PCM
- instrument cluster