Pinpoint Test Y: The Check Fuel Cap Indicator Is Never/Always On
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test Y: 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 Cluster (IC) a message over the communication network 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 IC does not receive the check fuel cap message and the check fuel cap indicator remains off.
If the IC does not receive the fuel cap off data from the PCM for 5 seconds or less, the IC defaults the check fuel cap indicator to the last setting, based upon the last known good data message. If the IC does not receive the fuel cap off data from the PCM for more than 5 seconds, the IC sets DTC U0100 in continuous memory and defaults the fuel cap OFF indicator off.
NOTE: If DTC U0100 is set in the IC, 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:
- PCM
- IC
PINPOINT TEST Y: THE CHECK FUEL CAP INDICATOR IS NEVER/ALWAYS ON
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Y1 CARRY OUT THE IC INDICATOR LAMP CONTROL ACTIVE COMMAND USING THE SCAN TOOL
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Select the 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 Y2.
No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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Y2 RETRIEVE THE RECORDED DTCs FROM BOTH CONTINUOUS AND ON-DEMAND PCM SELF-TESTS
- Check for recorded PCM DTCs from the continuous and on-demand self-tests.
- Is DTC P0457 recorded?
Yes
If the check fuel cap indicator is illuminated, REFER to Computers and Control Systems Information.
If the check fuel cap indicator is not illuminated, GO to Y3.
No
If the check fuel cap indicator is always on, INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). 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 IC to turn on the check fuel cap warning indicator.
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Y3 RETRIEVE THE RECORDED DTCs FROM BOTH THE CONTINUOUS AND ON-DEMAND IC SELF-TESTS
- Check for recorded IC DTCs from the continuous and on-demand self-tests.
- Are any DTCs recorded?
Yes
For DTC U0100, Go To Pinpoint Test AE. Pinpoint Tests AE: DTC U0100
For all other DTCs, REFER to DTC Charts. Instrumentation, Message Center and Warning Chimes
No
INSTALL a new PCM. TEST the system for normal operation.
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