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Tahoe / Yukon Service Manual

Malfunction Indicator Lamp (MIL) Diagnosis

Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5064146 Diagnostic Instructions Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions Circuit/System Description

Component Description
K20 Engine Control Module The control module controls a series of actuators to ensure optimal engine performance. The control module does this by reading values from a variety of sensors, interprets the data and adjusts the engine actuators accordingly.
P16 Instrument Cluster The instrument cluster houses several displays and gauges to inform the driver about various parameters of the vehicle.

The engine control module turns the MIL On by sending a request to the instrument cluster via serial data. The MIL should illuminate with the ignition/vehicle On and the engine Off. When the engine is started, the MIL should turn Off. Reference Information Scan Tool Reference Control Module References Circuit/System Verification

  1. Engine » Running
  2. Verify there are no DTCs set related to the following component/system: Engine Controls and Fuel ⇒ If any DTC is set Refer to: Diagnostic Trouble Code (DTC) List - Vehicle ⇓ If no DTC is set
  3. Verify the component works as specified: Malfunction Indicator Lamp (MIL) = Off ⇒ If the component does not work as specified Replace the component: P16 Instrument Cluster ⇓ If the component works as specified
  4. Ignition » On / Vehicle » In Service Mode Verify the component works as specified: Malfunction Indicator Lamp (MIL) = On ⇒ If the component does not work as specified Replace the component: P16 Instrument Cluster ⇓ If the component works as specified
  5. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Instrument Cluster Replacement For control module replacement, programming, and setup refer to: Control Module References