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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1469 (Engine Control System - 4.8L, 5.3L, & 6.0L - Troubleshooting & Diagnosis) >> Diagnostic Information & Procedures >> Malfunction Indicator Lamp (MIL) Inoperative >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 Chevrolet TrailBlazer, and 2004 Buick Rainier. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 4:  This step tests for a short to voltage on the MIL control circuit. With the fuse removed there should be no voltage on the MIL control circuit.
Malfunction Indicator Lamp (MIL) Inoperative

Step Action Values Yes No
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views
1 Did you perform the Diagnostic System Check-Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Engine Controls
2
  1. Verify that the instrument panel cluster (IPC) is operational. If the IPC is completely inoperative, refer to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gages and Console.
  2. Command the malfunction indicator lamp (MIL) ON and OFF with a scan tool.
Does the MIL turn ON and OFF when commanded with a scan tool?		 - Go to Intermittent Conditions  Go to Step 3 
3 Inspect the fuse that supplies ignition voltage to the cluster.
Is the fuse open?		 - Go to Step 10  Go to Step 4 
4 
  1. Turn OFF the ignition.
  2. Remove the fuse that supplies voltage to the MIL.
  3. Disconnect the powertrain control module (PCM).
  4. Turn ON the ignition, with the engine OFF.
  5. Measure the voltage from the MIL control circuit in the PCM harness connector to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems.
Is the voltage less than the specified value?		 0.3 V Go to Step 5  Go to Step 11 
5
  1. Turn OFF the ignition.
  2. Install the fuse that supplies voltage to the MIL.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a 3-amp fused jumper wire between the MIL control circuit in the PCM harness connector and a good ground.
Does the MIL illuminate?		 - Go to Step 9  Go to Step 6 
6
  1. Turn OFF the ignition.
  2. Remove the instrument panel cluster (IPC). Refer to Instrument Panel Cluster (IPC) Replacement in Instrument Panel, Gages, and Console.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the ignition voltage circuit of the IPC harness connector with a test lamp that is connected to a good ground.
Does the test lamp illuminate?		 - Go to Step 7  Go to Step 12 
7 Test the MIL control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct a condition?		 - Go to Step 15  Go to Step 8 
8 Test for an intermittent and for a poor connection at the IPC. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 15  Go to Step 13 
9 Test for an intermittent and for a poor connection at the PCM. Refer to Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 15  Go to Step 14 
10 Test all circuits and components that use this voltage supply for excessive current draw. Refer to Circuit Testing andWiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 15  Go to Intermittent Conditions 
11 Repair the short to voltage in the MIL control circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 15  -
12 Repair the open in the ignition voltage circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 15  -
13 Replace the IPC. Refer to Instrument Panel Cluster (IPC) Replacement in Instrument Panel, Gages, and Console.
Did you complete the replacement?		 - Go to Step 15  -
14 Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement .
Did you complete the replacement?		 - Go to Step 15  -
15
  1. Turn the ignition OFF for 30 seconds.
  2. Start the engine.
Does the MIL operate correctly?		 - Go to Step 16  Go to Step 2 
16 Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List System OK
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