Pinpoint Tests AA: The Check Fuel Cap Indicator Is Never/Always On
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test AA: The Check Fuel Cap Indicator Is Never/Always On
Normal Operation
The 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 Panel Cluster (IPC) a message over the High Speed Controller Area Network (HS-CAN) to turn on the check fuel cap indicator. 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 IPC does not receive the check fuel cap message and the check fuel cap message center indicator remains off.
If the IPC does not receive the fuel cap off data from the PCM for 5 seconds or less, the IPC defaults the check fuel cap indicator to the last setting, based upon the last known good fuel cap off message received.
If the IPC does not receive the fuel cap off data from the PCM for more than 5 seconds, the IPC sets DTC U0100:00 in continuous memory and defaults the check fuel cap indicator off.
- DTC P0457 (Evaporative Emission System Leak Detected [fuel cap loose/off]) - 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.
This pinpoint test is intended to diagnose the following:
- Fuel evaporative emissions concern
- IPC
PINPOINT TEST AA: THE CHECK FUEL CAP INDICATOR IS NEVER/ALWAYS ON
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AA1 CARRY OUT THE IPC INDICATOR LAMP CONTROL ACTIVE COMMAND USING THE SCAN TOOL
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IPC DataLogger .
- Select the IPC check fuel cap indicator (FUEL_CAP) active command. Command the check fuel cap indicator on and off. Observe the check fuel cap indicator.
- Does the check fuel cap indicator illuminate when commanded on and turn off when commanded off?
Yes
GO to AA2.
No
INSTALL a new IPC. REFER to Instrument Panel Cluster (IPC) Instrument Panel Cluster (IPC). TEST the system for normal operation.
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AA2 RETRIEVE THE RECORDED DTCs FROM THE PCM KOEO SELF-TEST
- Check for recorded PCM DTCs from the Key ON Engine OFF (KOEO) self-test.
- Is DTC P0457 recorded?
Yes
If the check fuel cap indicator is illuminated, REFER to Computers and Control Systems.
If the check fuel cap indicator is not illuminated, INSTALL a new PCM. REFER to Electronic Engine Controls Service and Repair. TEST the system for normal operation.
No
If the check fuel cap indicator is always on, INSTALL a new IPC. REFER to Instrument Panel Cluster (IPC) Instrument Panel Cluster (IPC). TEST the system for normal operation.
If the check fuel cap indicator is not illuminated, the system is operating normally at this time. If the fuel cap was left off and the check fuel cap warning indicator did not turn on, driving conditions may not have allowed for the PCM to run the cruise test and message the IPC to turn on the check fuel cap warning indicator.
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