Pinpoint Test W: The Malfunction Indicator Lamp (MIL) Is Never/Always On

Instrumentation, Message Center and Warning Chimes


Pinpoint Tests


Pinpoint Test W: The Malfunction Indicator Lamp (MIL) Is Never/Always On

Normal Operation

The Malfunction Indicator Lamp (MIL) is controlled by the Instrument Panel Cluster (IPC) 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 on/off state, based upon the last known good charging system status message received.

If the MIL status message is missing for more than 5 seconds, the IPC sets DTC U0100:00 in continuous memory and defaults the MIL on. If the MIL message is deemed invalid for longer than 5 seconds, the IPC defaults the MIL on.

NOTE: If DTC U0100:00 is set in the IPC, other observable symptoms may be an inoperative speedometer, tachometer or odometer.

This pinpoint test is intended to diagnose the following:

- PCM
- IPC



PINPOINT TEST W: THE MIL IS NEVER/ALWAYS ON

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W1 CARRY OUT THE IPC DEALER TEST MODE


- Ignition ON.
- Enter the IPC dealer test mode.
- Scroll through the displays to TELLTALE TEST and monitor the MIL indicator.
- Does the MIL indicator illuminate when in the dealer test mode and turn off when in normal operation mode?

Yes
GO to W2.

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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W2 RETRIEVE THE RECORDED DTCs FROM THE PCM KOEO SELF-TEST


- Check for recorded PCM DTCs from the Key ON Engine OFF (KOEO) self-test.
- Are any DTCs recorded?

Yes
DIAGNOSE all PCM DTCs first. REFER to Computers and Control Systems Information.

No
GO to W3.

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W3 RETRIEVE THE RECORDED DTCs FROM THE IPC SELF-TEST


- Check for recorded DTCs from the IPC self-test.
- Are any DTCs recorded?

Yes
For DTC U0100:00, Go To Pinpoint Test AT. Pinpoint Tests AT: DTC U0100:00

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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