GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 2001 🢒 Intrigue 🢒 Body and Accessories 🢒 Lighting Systems 🢒 DTC B2618

Circuit Description

The body control module (BCM) controls the courtesy lamps through the courtesy lamp supply voltage circuit. The BCM grounds the courtesy lamp low control circuit which completes the courtesy lamp circuit.

Conditions for Running the DTC

The BCM must command the interior lamp control circuit ON.

Conditions for Setting the DTC
    • The BCM detects a high when the output should be low in the interior lamp control circuit.
    • The condition above must be present for more than 0.3 seconds.

Action Taken When the DTC Sets

The BCM stores DTC B2618 in memory.

Conditions for Clearing the DTC
    • A current DTC B2618 will clear if the short to battery in the interior lamp control circuit is no longer detected by the BCM.
    • A history DTC B2618 will clear after 100 consecutive ignition cycles if the condition for the condition is no longer present and no other BCM faults are detected.
    • The BCM receives the clear code command from the scan tool.

Diagnostic Aids
    • If the DTC B2618 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • The following conditions may cause an intermittent condition to occur:
       - An intermittent short to battery in the interior lamp control circuit.
       - Any courtesy lamp is intermittently shorted to battery.
       - The BCM is intermittently shorted to battery.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Watch for the courtesy lamps to illuminate. Command both the ON and OFF states. Repeat the commands as necessary.

    2.

  2. Tests for a short to voltage in the interior lamp output circuit.

Step

Action

Yes

No

Schematic Reference: Interior Lights Schematics

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 light test - theater dimming #1 output to ON and OFF.

Do the courtesy lamps turn ON and OFF with each command?

Go to Diagnostic Aids

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect one of the courtesy lamp.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the courtesy lamp low control circuit of the courtesy lamp with a test lamp that is connected to ground.

Does the test lamp illuminate?

Go to Step 4

Go to Step 5

4

Test the courtesy lamp low control circuit for a short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 6

Go to Step 5

5

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 7

Go to Step 6

6

Important: Perform the set up procedure for the BCM.

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 7

--

7
  1. Use the scan tool in order to clear the DTC.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC set again?

Go to Step 2

System OK