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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1799 (IMMOBILIZER SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESDTC B2947TEST DESCRIPTION
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Test Description

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Test Description
WARNING: This page is about a different car, the 2007 Saturn Vue. 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. 2:  This step verifies that DTC B2947 is a current DTC.
  2. 3:  This step tests for a short to ground in the Passlock™ sensor or the pigtail harness.
DTC B2947

Step Action Yes No
Schematic Reference: Theft Deterrent System Schematics
Connector End View Reference: Vehicle Access Connector End Views
1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2  Go to Diagnostic System Check - Vehicle
2 
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Select the body control module display DTCs function on the scan tool.
Does the scan tool display DTC B2947 as a current DTC?		 Go to Step 3  Go to Testing for Intermittent Conditions and Poor Connections
3 
  1. Disconnect the Passlock™ sensor connector.
  2. Measure the voltage between the Passlock™ 12-volt reference circuit and a good ground.
Does the voltage measure approximately battery voltage?		 Go to Step 6  Go to Step 4 
4 Test the Passlock™ battery voltage circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 Go to Step 10  Go to Step 5 
5 Inspect for poor connections at the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 Go to Step 10  Go to Step 7 
6 Inspect for poor connections at the Passlock™ sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 Go to Step 10  Go to Step 8 
7 Replace the BCM. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?		 Go to Step 10  -
8 Replace the Passlock™ sensor. Refer to Ignition Lock Cylinder Case Replacement .
Did you complete the replacement?		 Go to Step 9  -
9 Perform the Passlock™ learn procedure. Refer to Programming Immobilizer System Components .
Did you complete the procedure?		 Go to Step 10  -
10
  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 3  System OK
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.