Fuel System - MIL ON/DTC P0457 Set
NUMBER: 14-001-06GROUP: 14 - Fuel System
DATE: January 21, 2006
SUBJECT:
Loose Fuel Cap Message or MIL Illumination for Diagnostic Trouble Code P0457 - EVAP System - Loose Fuel Cap
MODELS:
2005 - 2006 (ND) Dakota
2005 - 2006 (CS) Pacifica
2006 (DR/DH) Ram Truck
2005 - 2006 (HB) Durango
2005 - 2006 (KJ) Liberty
2006 (LX) 300/Magnum/Charger
2006 (PT) PT Cruiser
2007 (PM) Caliber
2006 (RS) Town & Country/Caravan/Voyager
2006 (TJ) Wrangler
2005 - 2006 (WK) Grand Cherokee
2006 (XK) Commander
NOTE:
This bulletin applies to all vehicles equipped with a gasoline engine.
NOTE:
Do not replace the gas cap if only DTC P0457 - Evap System - Loose Fuel Cap is present.
DISCUSSION:
Starting with the introduction of 2005 model year vehicles a new diagnostic trouble code (DTC) P0457 - Evap System - Loose Fuel Cap was introduced. Also added to some vehicles was an instrument cluster message in the odometer display or message center (EVIC) that alerts the driver that the gas cap is loose.
The PCM monitors the fuel level for a "significant" change in either direction and remembers that this has recently occurred. A loose fuel cap DTC, cluster message or message center message matures when the check for the EVAP system large leak condition fails after the fuel level change event. If a leak of greater than 0.090" is observed after a fuel level change, a loose cap diagnostic single trip failure is stored and the cluster message or message center message is displayed even though a DTC may not yet be present. DTC P0457 - Evap System - Loose Fuel Cap is stored and the MIL illuminated after 2 cold start failures of the large leak diagnostic checks following a fuel change event. Only the passing of one of the 3 EVAP system diagnostic routines large leak, small leak or loose gas cap) by the PCM will validate that the cap is no longer loose and turn off the MIL light or message.
For 2007 model vehicles DTC P0457 - Evap System - Loose Fuel Cap will be stored and the MIL illuminated after 3 cold starts.
To temporarily clear the gas cap loose message from the odometer or message center press the reset button on the odometer or message center while the message is being displayed. This clears the message for the current key cycle only.
NOTE:
The above works for all vehicles except, 2005 - 2006 Grand Cherokee or Commander. For these, the scantool must be used)
To clear the gas cap loose message from the odometer or message center ensure the gas cap is tight and let the vehicle run the small leak diagnostic routine. The small leak diagnostic routine will pass a sealed system after an 8 hour soak and a negative 3° C change in fuel temperature from the last key cycle.
NOTE:
A heated garage may effect the small leak diagnostic routine.
To clear the gas cap loose message from the odometer or message center and matured DTC (MIL light) diagnose and repair the leak and then erase DTC's with the DRBIII(R)/StarSCAN(TM) scantool
NOTE:
The DRBIII(R)/StarSCAN(TM) scantool may be used to reset the Loose Cap message. Select the PCM Reset function on StarSCAN(TM) (version 6.05_SPI or higher) or the Clear PCM Batt Disconnect function on DRB III(R). Disconnecting and reconnecting the battery will also clear the message.
If a gas cap loose message is displayed or DTC P0457 - Evap System - Loose Fuel Cap is set without P0455 - Evap System Large Leak then ensure the gas cap it tight, no further service action is required.
POLICY:
Information Only.
Disclaimer:
This bulletin is supplied as technical information only and is not an authorization for repair.