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Home >> Chevrolet >> 2006 >> Cobalt LTZ >> Repair and Diagnosis >> External Pages >> Different car >> Section 704 (Engine Controls And Fuel - 2.0L - Diagnosis & Troubleshooting) >> Malfunction Indicator Lamp (MIL) Inoperative >> Circuit Description >> Test Description

Test Description

WARNING: This page is about a different car, the 2007 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 3:  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: Powertrain Control Module Connector End Views or Engine Controls Connector End Views
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to DIAGNOSTIC SYSTEM CHECK - VEHICLE
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 
  1. Turn OFF the ignition.
  2. Remove the fuse that supplies voltage to the instrument panel cluster (IPC).
  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.
Is the voltage less than the specified value?		 0.3 V Go to Step 4  Go to Step 8 
4
  1. Turn OFF the ignition.
  2. Install the fuse that supplies voltage to the IPC.
  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.
Is the MIL illuminated?		 - Go to Step 7  Go to Step 5 
5 Test the MIL control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct a condition?		 - Go to Step 11  Go to Step 6 
6 Test for an intermittent and for a poor connection at the IPC. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 11  Go to Step 9 
7 Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs
Did you find and correct the condition?		 - Go to Step 11  Go to Step 10 
8 Repair the short to voltage in the MIL control circuit. Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 11  -
9 Replace the IPC. Refer to Instrument Cluster Replacement .
Did you complete the replacement?		 - Go to Step 11  -
10 Replace the PCM. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 11  -
11
  1. Remove all test equipment.
  2. Connect any disconnected components or any disconnected fuses.
  3. Turn OFF the ignition for 30 seconds.
  4. Start the engine and operate the vehicle to verify the performance, and driveability.
  5. Observe the MIL, the vehicle performance, and the driveability.
Does the vehicle operate correctly, without MIL illumination and without stored DTCs?		 - System OK Go to Diagnostic Trouble Code (DTC) List - Vehicle
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