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

Instrumentation, Message Center and Warning Chimes

Pinpoint Tests

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

Normal Operation

The Instrument Cluster (IC) receives the Malfunction Indicator Lamp (MIL) data from the PCM over the High Speed Controller Area Network (HS-CAN) communication bus. If an emissions concern exists, the PCM sets a DTC and sends a message to the IC to illuminate the MIL. If a mis-fire condition exists, the PCM sets a DTC and sends the IC a message to flash the MIL. If the MIL message is missing or if the data is deemed invalid by the IC for greater than 5 seconds, the IC sets DTC U0100 and defaults the MIL on.

NOTE: If DTC U0100 is set in the IC other symptoms may also be present such as an inoperative speedometer, tachometer or temperature gauge.

This pinpoint test is intended to diagnose the following:

- PCM
- IC



PINPOINT TEST S: THE MIL IS NEVER/ALWAYS ON

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S1 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST


- Check for recorded IC DTCs from the self-test.
- Is DTC U0100 recorded?

Yes
GO to Pinpoint Test AT. Pinpoint Tests AT: DTC U0100

No
GO to S2.

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S2 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
REFER to Computers and Control Systems Information.

No
GO to S3.

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S3 CARRY OUT THE IC INDICATOR LAMP ACTIVE COMMAND USING THE SCAN TOOL


- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger .
- Select the IC MIL (MIL_IC) active command on and off. Observe the MIL.
- Does the MIL illuminate when commanded on and turn off when commanded off?

Yes
INSTALL a new PCM. REFER to Computers and Control Systems. TEST the system for normal operation.

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

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