Pinpoint Test S: The Malfunction Indicator Lamp (MIL) Is Never/Always On
Normal Operation
The malfunction indicator lamp (MIL) is controlled by the instrument cluster (IC) using data sent from the PCM over the high speed controller area network (HS-CAN) communication bus. If the MIL status message is missing for less than 5 seconds, the MIL remains in the last indication mode (on or off). If the MIL status message is missing for more than 5 seconds, the instrument cluster (IC) sets DTC U0100 in continuous memory and defaults the MIL on.
NOTE:
If DTC U0100 is set in the instrument cluster (IC), other observable symptoms may be an inoperative speedometer, tachometer or odometer.
This pinpoint test is intended to diagnose the following:
- PCM
- Instrument cluster (IC)
PINPOINT TEST S: THE MALFUNCTION INDICATOR LAMP (MIL) IS NEVER/ALWAYS ON
- S1 CARRY OUT THE INSTRUMENT CLUSTER (IC) INDICATOR LAMP CONTROL ACTIVE COMMAND USING THE SCAN TOOL
- Key in ON position.
- Enter the following diagnostic mode on the diagnostic tool: Instrument Cluster (IC) DataLogger
- Select the instrument cluster (IC) MIL (MIL_IC) active command mode and command the MIL on and off. Observe the MIL.
- Does the MIL illuminate when commanded on, and turn off when commanded off?
- S2 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.
- Are any PCM DTCs recorded?
- YES : REFER to the Introduction - Gasoline Engines article.
- NO : Go to S3.
- S3 RETRIEVE THE RECORDED DTCs FROM BOTH THE CONTINUOUS AND ON-DEMAND INSTRUMENT CLUSTER (IC) SELF-TESTS
- Check for recorded instrument cluster (IC) DTCs from the continuous and on-demand self-tests.
- Is DTC U0100 recorded?
- YES : Go to Pinpoint Test AG .
- NO : Go to S4.
- S4 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the PCM connectors and make sure they seat correctly.
- Operate the system and determine if the concern is still present.
- Is the concern still present?
- YES : INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS article. TEST the system for normal operation.
- NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
- S5 CHECK FOR CORRECT INSTRUMENT CLUSTER (IC) OPERATION
- Disconnect the instrument cluster (IC) connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the instrument cluster (IC) connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
- YES : INSTALL a new instrument cluster (IC). REFER to Instrument Cluster (IC) . TEST the system for normal operation.
- NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.