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

Instrumentation, Message Center and Warning Chimes

Pinpoint Test U: 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 (Malfunction Indicator Lamp) status message is missing for less than 5 seconds, the MIL (Malfunction Indicator Lamp) remains in the last on or off state based upon the last known good charging system status message received. If the MIL (Malfunction Indicator Lamp) status message is missing for more than 5 seconds, the IPC (Instrument Panel Cluster) sets DTC U0100:87 in continuous memory and defaults the MIL (Malfunction Indicator Lamp) on. If the MIL (Malfunction Indicator Lamp) message is deemed invalid for longer than 5 seconds, the IPC (Instrument Panel Cluster) defaults the MIL (Malfunction Indicator Lamp) on.

NOTE: If DTC U0100:87 is set in the IPC (Instrument Panel Cluster) , other observable symptoms can be an inoperative speedometer, tachometer or odometer.

This pinpoint test is intended to diagnose the following:

- PCM

- IPC (Instrument Panel Cluster)

PINPOINT TEST U : THE MIL (Malfunction Indicator Lamp) IS NEVER/ALWAYS ON

U1 CARRY OUT THE IPC (Instrument Panel Cluster) WARNING LAMPS AND CHIME ACTIVE COMMAND USING THE SCAN TOOL

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: IPC (Instrument Panel Cluster) DataLogger.

- Select the IPC (Instrument Panel Cluster) MIL (Malfunction Indicator Lamp) (MIL) active command. Command the MIL (Malfunction Indicator Lamp) on and off while observing the MIL (Malfunction Indicator Lamp).

Does the MIL (Malfunction Indicator Lamp) illuminate when selected on, and turn off when selected off?

Yes
GO to U2.

No
INSTALL a new IPC (Instrument Panel Cluster). REFER to Instrument Panel Cluster (IPC) . TEST the system for normal operation.

U2 RETRIEVE THE RECORDED PCM DTCs FROM THE KOEO (Key ON Engine OFF) 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 U3.

U3 RETRIEVE THE RECORDED DTCs FROM THE IPC (Instrument Panel Cluster) SELF-TEST

- Check for recorded DTCs from the IPC (Instrument Panel Cluster) self-test.

Are any DTCs recorded?

Yes
For DTC U0100:87, GO to Pinpoint Test AQ Pinpoint Test AQ: DTC U0100:87.

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.