FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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Test Q: The Malfunction Indicator Lamp (MIL) Is Never/Always On

PINPOINT TEST Q: THE MALFUNCTION INDICATOR LAMP (MIL) IS NEVER/ALWAYS ON

Normal Operation
The MIL is controlled by the instrument cluster 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 sets DTC U0100 in continuous memory and defaults the MIL on. If the MIL message is deemed invalid for longer than 5 seconds, the instrument cluster defaults the MIL on.

NOTE: If DTC U0100 is set in the instrument cluster, other observable symptoms may be an inoperative speedometer, tachometer or odometer.

This pinpoint test is intended to diagnose the following:
- PCM
- Instrument cluster


Q1-Q5: