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

Instrumentation and Warning Chimes

Pinpoint Tests

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

Normal Operation

The Instrument Cluster (IC) receives the MIL status from the PCM over the High Speed Controller Area Network (HS-CAN) communication bus. When a fault condition exists in the PCM, a DTC is set in the PCM and a message is sent to the IC to illuminate the MIL. The IC sets a continuous DTC if the PCM data is missing for more than 5 seconds or if invalid data is received and the IC turns on the MIL.

This pinpoint test is intended to diagnose the following:

- PCM
- IC

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

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Q1 RETRIEVE THE RECORDED DTCs FROM THE PCM KOEO SELF-TEST

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

Yes
REFER to Computers and Control Systems.

No
GO to Q2.

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Q2 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST

- Retrieve the recorded DTCs from the IC self-test.
- Is DTC U0100 retrieved?

Yes
GO to Pinpoint Test AK. Pinpoint Test AK: DTC U0100

No
GO to Q3.

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Q3 CARRY OUT THE IC INDICATOR LAMP CONTROL ACTIVE COMMAND USING THE SCAN TOOL

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

Yes
If the MIL is never on, the system is operating correctly at this time.

If the MIL is always on, INSTALL a new PCM. REFER to Electronic Engine Controls Service and Repair. 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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