Test E: The Check Fuel Cap Warning Is Inoperative

PINPOINT TEST E: THE CHECK FUEL CAP WARNING IS INOPERATIVE

E1-E2:

Normal Operation
The powertrain control module (PCM) monitors the fuel tank evaporative emission system for significant leaks that occur following refueling of the vehicle. Once the PCM detects a fuel vapor leak, the PCM sends the instrument cluster a message over the communication network to turn on the check fuel cap warning message. DTC P0457 sets in the PCM following a successful cruise test, which is initiated when the vehicle is driven at a steady speed above 64 km/h (40 mph) for a duration of approximately 4-5 minutes. If the PCM is unable to successfully run the cruise test, the instrument cluster does not receive the check fuel cap message and the check fuel cap warning remains off. DTC P0457 sets in the PCM if a fuel tank pressure change greater than -23.7 kPa (-7 in-Hg) of vacuum within 30 seconds after refueling occurs, or there is an excessive purge (fuel vapor) flow of greater than 454 g (1.0 lb) per minute.

Possible Causes
- Instrument cluster