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

Instrumentation, Message Center and Warning Chimes

Pinpoint Tests

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

Normal Operation

The Malfunction Indicator Lamp (MIL) is controlled by the Instrument Cluster (IC) using data sent from the PCM over the communication network. When an emission system concern exists, the PCM sets a DTC and sends the IC a message to turn on the MIL.

This pinpoint test is intended to diagnose the following:

- PCM
- IC



PINPOINT TEST T: THE MIL IS NEVER/ALWAYS ON

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T1 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 PCM DTCs recorded?

Yes
REFER to Computers and Control Systems Information.

No
GO to T2.

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T2 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST


- Check for recorded continuous memory IC DTCs.
- Is DTC U1900 recorded?

Yes
REFER to Information Bus to diagnose communication with the PCM.

No
GO to T3.

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T3 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 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 Information. 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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