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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1022 (Engine Controls Diagnosis - 6.6L (Lb7) (DTCS P0612 To P2141)) >> Diagnosis >> DTC P0650 >> 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. 4:  This step tests for a short to ground in the MIL control circuit. With the Engine Control Module (ECM) disconnected and the ignition ON, the MIL should be OFF.
  2. 5:  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.
DTC P0650

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematic Icons 
Connector End View Reference:  Engine Controls Connector End Views  or  Engine Control Module (ECM) 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 whether the instrument cluster is operational. If the instrument panel (IP) is completely inoperative, refer to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gages and Console.
  2. Command the MIL ON and OFF with a scan tool.
Does the MIL turn ON and OFF when commanded with a scan tool?		 - Go to Step 3  Go to Step 4 
3
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Does the DTC fail this ignition?		 - Go to Step 4  Go to Intermittent Conditions
4 
  1. Turn OFF the ignition.
  2. Disconnect the engine control module (ECM). Refer to Engine Control Module (ECM) Replacement .
  3. Turn ON the ignition.
Is the malfunction indicator lamp (MIL) OFF?		 - Go to Step 5  Go to Step 10 
5 
  1. Remove the fuse that supplies voltage to the IPC.
  2. Measure the voltage from the MIL control circuit in the ECM harness connector to a good ground.
Is the voltage less than the specified value?		 1 V Go to Step 6  Go to Step 11 
6
  1. Turn OFF the ignition.
  2. Install the fuse that supplies ignition 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 of the ECM harness connector and a good ground.
Is the MIL illuminated?		 - Go to Step 9  Go to Step 7 
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 14  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 Repairs.
Did you find and correct the condition?		 - Go to Step 14  Go to Step 12 
9 Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Repairs.
Did you find and correct the condition?		 - Go to Step 14  Go to Step 13 
10 Test for a short to ground in the MIL control circuit. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 14  Go to Step 12 
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 14  -
12 Replace the IPC. Refer to Instrument Panel Cluster (IPC) Replacement in Instrument Panel, Gages, and Console.
Did you complete the replacement?		 - Go to Step 14  -
13 Replace the ECM. Refer to Engine Control Module (ECM) Replacement .
Did you complete the replacement?		 - Go to Step 14  -
14
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?		 - Go to Step 2  Go to Step 15 
15 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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