Pinpoint Test AJ: The Check Fuel Cap Message Center Indicator Is Never/Always On
Instrumentation, Message Center and Warning Chimes
Pinpoint Test AJ: The Check Fuel Cap Message Center 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 communication network to turn on the check fuel cap message center indicator. The PCM carries out a cruise test 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 successfully carries out the cruise test and determines that the fuel cap is off, DTC P0457 sets and sends a message to the IPC (Instrument Panel Cluster) to turn on the check fuel cap message center indicator. If the PCM is unable to successfully run the cruise test, the PCM does not send the IPC (Instrument Panel Cluster) a message to turn on the check fuel cap message center indicator.
If the fuel cap off status message is missing for less than 5 seconds, the IPC (Instrument Panel Cluster) defaults the check fuel cap message center indicator to the last on/off status based upon the last known good fuel cap off status message received.
If the IPC (Instrument Panel Cluster) does not receive the fuel inlet status from the PCM for 5 seconds, the IPC (Instrument Panel Cluster) sets DTC U0100:00 in continuous memory and defaults the check fuel cap message center indicator off.
NOTE: If DTC U0100:00 is set in the IPC (Instrument Panel Cluster), other observable symptoms may be an inoperative speedometer, temperature gauge or odometer.
- 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:
- Evaporative emission system concern
- IPC (Instrument Panel Cluster)
PINPOINT TEST AJ : THE CHECK FUEL CAP MESSAGE CENTER INDICATOR IS NEVER/ALWAYS ON
AJ1 VERIFY THE OPERATION OF THE POWERTRAIN MALFUNCTION (WRENCH) AND ENGINE OVER-TEMPERATURE MESSAGE CENTER INDICATORS
- Ignition OFF.
- Disconnect: PCM C175B.
- Ignition ON.
- NOTE: If multiple warnings are present, the message center indicators rotate through each of the warnings. Allow the displays to rotate through each display while determining whether the powertrain malfunction (wrench) and over-temperature message center indicators are active.
Observe the message center or integrated display area of the IPC (Instrument Panel Cluster) with the PCM connected and disconnected.
Do the powertrain malfunction (wrench) and engine over-temperature message center warning indicators remain off when the PCM is connected and become active with the PCM disconnected?
Yes
GO to AJ2.
No
INSTALL a new IPC (Instrument Panel Cluster). REFER to Instrument Panel Cluster (IPC) . TEST the system for normal operation.
AJ2 RETRIEVE THE RECORDED DTCs FROM THE PCM KOEO (Key ON Engine OFF) 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 message center indicator is illuminated, REFER to Computers and Control Systems Information.
If the check fuel cap message center indicator is not illuminated, GO to AJ3.
No
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 message center indicator did not turn on, driving conditions may not have allowed for the PCM to run the cruise test and message the IPC (Instrument Panel Cluster) to turn the check fuel cap message center indicator on.
AJ3 RETRIEVE THE RECORDED DTCs FROM THE IPC (Instrument Panel Cluster) SELF-TEST
- Check for recorded IPC (Instrument Panel Cluster) DTCs from the self-test.
Are any DTCs recorded?
Yes
For DTC U0100:00, GO to Pinpoint Test AU. Pinpoint Test AU: DTC U0100:00
For all other DTCs, REFER to the DTC Charts. Instrumentation, Message Center and Warning Chimes
No
INSTALL a new PCM. TEST the system for normal operation.