LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 999 (Engine Controls - 4.8L, 5.3L, & 6.0L (Troubleshooting & Diagnosis)) >> Troubleshooting >> Malfunction Indicator Lamp (MIL) Inoperative >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. 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. 3:  This step determines if the condition is with the MIL control circuit or the PCM.
  2. 4:  This step determines if a voltage is being applied to the control circuit.
Malfunction Indicator Lamp (MIL) Inoperative

Step Action 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 Inspect the fuse that supplies voltage to the MIL.
Is the fuse open?		 Go to Step 10  Go to Step 3 
3 
  1. Turn OFF the ignition.
  2. Disconnect the PCM. Refer to Powertrain Control Module (PCM) Replacement
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a 3-amp fused jumper wire between the MIL control circuit and a good ground.
  5. Observe the MIL.
Is the MIL illuminated?		 Go to Step 9  Go to Step 4 
4  Did the fuse in the jumper wire open? Go to Step 11  Go to Step 5 
5
  1. Remove the instrument panel cluster (IPC). Refer to Instrument Panel Cluster (IPC) Replacement in Instrument Panel, Gauges, and Console.
  2. Test the MIL control circuit for an open between the PCM and the IPC. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 14  Go to Step 6 
6 Probe the MIL battery positive voltage circuit at the IPC harness connector with a test lamp connected to a good ground.
Does the test lamp illuminate?		 Go to Step 8  Go to Step 7 
7 Repair the open in the MIL battery positive voltage circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 14  -
8 Inspect for poor connections at the harness connector of the IPC and repair as necessary. 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 14  Go to Step 12 
9 Inspect for poor connections at the harness connector of the IPC and repair as necessary. 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 14  Go to Step 13 
10
  1. Repair the short to ground in the MIL battery positive voltage circuit. Refer to Wiring Repairs in Wiring Systems.
  2. Replace the fuse.
Did you complete the repair?		 Go to Step 14  -
11 Repair the short to voltage in battery positive voltage circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 14  -
12 Replace the (IPC). Refer to Instrument Panel Cluster (IPC) Replacement in Instrument Panel, Gauges, and Console.
Did you complete the replacement?		 Go to Step 14  -
13 Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement
Did you complete the replacement?		 Go to Step 14  -
14 Operate the system in order to verify the repair.
Did you correct the condition?		 System OK Go to Step 2 
scientia non olet · About LEMON Manuals