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HOMESERVICE MANUALSCHEVROLET2006CHEVY EXPRESS G2500, VAN CARGO, 6.6 2REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 945 (IMMOBILIZER SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESDTC B2948TEST DESCRIPTION
2006 Chevrolet Chevy Express G2500, Van Cargo, 6.6 2

Test Description

2006 Chevrolet Chevy Express G2500, Van Cargo, 6.6 2SECTION Test Description
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2007 GMC Savana Special, 2007 GMC Savana Camper Special, 2007 GMC Savana, 2007 Chevrolet RV Cutaway, and 2007 Chevrolet Cutaway. 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 battery positive on the Passlock™ battery voltage circuit.
DTC B2948

Step Action Yes No
Schematic Reference: Immobilizer Schematics 
Connector End View Reference: Immobilizer 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 B2948 as a current DTC?		 Go to Step 3  Go to Testing for Intermittent Conditions and Poor Connections
3 
IMPORTANT: The use of a DMM is crucial in this step because voltage may be measured for 10 milliseconds.
  1. Disconnect the Passlock™ sensor connector.
  2. Connect a DMM between the Passlock™ battery voltage circuit and a good ground.
  3. Set the MIN MAX mode to the one millisecond peak and start to record.
  4. Turn OFF the ignition.
  5. Stop recording and review the recorded MIN value.
Does the voltage measure near 0 volts?		 Go to Step 7  Go to Step 4 
4 Test the Passlock™ battery voltage circuit for a short to voltage. 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 6 
6 Inspect for poor connections at the Passlock™ sensor. Refer to Testing for Intermittent Conditions and Poor Connections .
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 repair?		 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
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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.