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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 958 (Instrument Panel System Displays, Gauges And Console) >> Diagnostic Information and Procedures >> DTC P0381: Wait to Start Lamp Control Circuit >> Diagnostic Aids

Diagnostic Aids

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.
IMPORTANT: Remove any debris from the ECM connector surfaces before servicing the ECM. Inspect the ECM connector gaskets when diagnosing/replacing the ECM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the ECM.

Using Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can aid in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also aid determining how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that you observed. This will isolate when the DTC failed.

The wait to start indicator illuminates only with the ignition ON and the engine OFF. The wait to start indicator will not illuminate during post-start glow plug operation.

The wait to start indicator will not stay ON for long at higher engine temperatures.

For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

DTC P0381

Step Action Value(s) Yes No
Schematic Reference: Instrument Cluster Schematics 
Connector End View Reference: Engine Control Module (ECM) Connector End Views in Engine Controls - 6.6L (LB7), and Engine Control Module (ECM) Connector End Views in Engine Controls - 6.6L (LLY)
1 Did you perform the Instrument Cluster Diagnostic System Check? - Go to Step 2  Go to Diagnostic System Check - Instrument Cluster 
2 Turn ON the ignition, with the engine OFF.
Does the wait to start indicator illuminate and then turn OFF?		 - Go to Diagnostic Aids Go to Step 3 
3
  1. Turn OFF the ignition.
  2. Disconnect the engine control module (ECM) connector C2.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the wait to start signal circuit of the ECM to a good ground.
Does the voltage measure greater than the specified value?		 9.5 V Go to Step 4  Go to Step 6 
4 Test the wait to start signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 8  Go to Step 5 
5 Inspect for poor connections at the harness connector of the ECM. 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 8  Go to Step 7 
6 Repair the short to ground in the wait to start signal circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 8  -
7
IMPORTANT: Program the replacement ECM.
Replace the ECM. Refer to the following procedures:Did you complete the replacement?		 - Go to Step 8  -
8
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?		 - Go to Step 2  System OK
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