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Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 11 (Engine Controls - 4.3L - Troubleshooting & Diagnosis) >> Malfunction Indicator Lamp (MIL) Always On >> Test Description

Test Description

WARNING: This page is about a different variant/trim than selected.

The number below refers to the step number on the diagnostic table.

  1. 2:  This step determines if the condition is with the MIL control circuit or the PCM.
Malfunction Indicator Lamp (MIL) Always On

Step Action Yes No
Schematic Reference: Instrument Cluster Schematics or Engine Controls Schematics
Connector End View Reference: Instrument Panel, Gages, and Console Connector End Views or Powertrain Control Module (PCM) Connector End Views
1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2  Go to Diagnostic System Check - Vehicle
2
  1. Turn OFF the ignition.
  2. Disconnect the powertrain control module (PCM).
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the malfunction indicator lamp (MIL).
Is the MIL illuminated?
Go to Step 3  Go to Step 5 
3
  1. Remove the instrument panel cluster (IPC). Refer to Instrument Panel Cluster (IPC) Replacement .
  2. Test the MIL control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?
Go to Step 6  Go to Step 4 
4 Replace the IPC. Refer to Instrument Panel Cluster (IPC) Replacement .
Did you complete the replacement?
Go to Step 6  -
5 Replace the PCM. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?
Go to Step 6  -
6
  1. Turn the ignition OFF for 30 seconds.
  2. Start the engine.
Does the vehicle operate correctly without any MIL illumination, and without any stored DTCs?
System OK Go to Diagnostic Trouble Code (DTC) List - Vehicle