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HOMESERVICE MANUALSCHEVROLET2001CHEVY EXPRESS G2500, VAN PASSENGER EXTENDED, 5.0 MREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 919 (LIGHTING SYSTEMS)DIAGNOSTIC INFORMATION AND PROCEDURESDTC B2618TEST DESCRIPTION
2001 Chevrolet Chevy Express G2500, Van Passenger Extended, 5.0 M

Test Description

2001 Chevrolet Chevy Express G2500, Van Passenger Extended, 5.0 MSECTION Test Description
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2001 GMC Yukon XL, 2001 GMC Yukon, 2001 GMC Sierra, 2001 GMC Cab & Chassis Sierra, and 2001 GMC C3500 HD. However, it is still accessible from the selected car via links, so may be relevant.

The number(s) below refer to the step number(s) on the diagnostic table.

  1. 2 

    Listen for an audible click when the courtesy lamp relay operates. Command both the ON and OFF states. Repeat the commands as necessary.

  2. 3 

    Tests for voltage at the coil side of the courtesy lamp relay. The CTSY fuse supplies power to the coil side of the courtesy lamp relay.

  3. 4 

    Verifies that the body control module is providing ground to the courtesy lamp relay.

  4. 5 

    Tests if ground is constantly being applied to the courtesy lamp relay.

  5. 12 

    After replacement of the BCM you must calibrate the new module for proper operation.

DTC B2618

Step Action Yes No
1 Did you perform the Lighting System Diagnostic System Check? Go to Step 2  Go to Diagnostic System Check - Lighting Systems 
2 
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the courtesy lamp relay ON and OFF.
Does the courtesy lamp relay turn ON and OFF with each command?		 Go to Diagnostic Aids Go to Step 3 
3 
  1. Turn OFF the ignition.
  2. Disconnect the courtesy lamp relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the courtesy lamp supply voltage circuit, coil side of the courtesy lamp relay and a good ground.
Does the test lamp illuminate?		 Go to Step 4  Go to Step 10 
4 
  1. Connect a test lamp between the courtesy lamp relay coil control circuit of the courtesy lamp relay and the courtesy lamp supply voltage circuit, coil side of the courtesy lamp relay .
  2. With a scan tool, command the courtesy lamp relay ON and OFF .
Does the test lamp turn ON and OFF with each command?		 Go to Step 8  Go to Step 5 
5  Does the test lamp remain illuminated with each command? Go to Step 7  Go to Step 6 
6 Test the courtesy lamp relay coil control circuit of the courtesy lamp relay for high resistance, an open, or a short to voltage. Refer to Circuit Testing , and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 13  Go to Step 9 
7 Test the courtesy lamp relay coil control circuit of the courtesy lamp relay for a short to ground. Refer to Circuit Testing , and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 13  Go to Step 9 
8 Inspect for poor connections at the courtesy lamp relay. 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 13  Go to Step 11 
9 Inspect for poor connections at the harness connector of the body control module. 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 13  Go to Step 12 
10 Repair the courtesy lamp supply voltage circuit, coil side of the courtesy lamp relay. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 13  -
11 Replace the courtesy lamp relay.
Did you complete the replacement?		 Go to Step 13  -
12 
IMPORTANT:

Perform the setup procedure for the body control module.

Replace the body control module. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?		 Go to Step 13  -
13
  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
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.