GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2000 🢒 Impala 🢒 Body and Accessories 🢒 Lighting Systems 🢒 DTC B2618 Pass Compartment Dimming #2 Circuit High

Circuit Description

The Body Control Module (BCM) controls the footwell lamps through the theater dimming control circuit. The BCM grounds the theatre dimming ground control circuit which completes the footwell lamps ground circuit, and the lights illuminate.

Conditions for Running the DTC

The BCM must command the theater dimming control feature ON.

Conditions for Setting the DTC
    • The BCM detects a high when the output should be low in the theater dimming ground 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 theatre dimming ground 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 malfunction is no longer present and no other BCM faults are detected..

Diagnostic Aids
    • If the DTC B2618 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections .
    • The following conditions may cause an intermittent malfunction to occur:
       - An intermittent short to battery in the theatre dimming ground control circuit
       - Either footwell lamp is intermittently shorted to battery internally
       - The BCM is intermittently shorted to battery internally

Test Description

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

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

    2.

  2. Tests for voltage at the footwell lamps. The I/P-BRP fuse supplies power to the footwell lamps.

    3.

  3. Verifies that the Body Control Module is providing ground to the footwell lamps.

    4.

  4. Tests if ground is constantly being applied to the footwell lamps.

Step

Action

Yes

No

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to A Diagnostic System Check - Lighting Systems in 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 footwell lamps turn ON and OFF with each command?

Go to Diagnostic Aids

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the footwell lamps.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the feed circuit of the footwell lamps with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 4

Go to Step 10

4

  1. Connect a test lamp between the control circuit of the footwell lamps and the feed circuit of the footwell lamps.
  2. With a scan tool, command the footwell lamps 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 control circuit of the footwell lamps for high resistance or an open. 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 control circuit of the footwell lamps 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 each footwell lamp. Refer to Testing for Intermittent 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 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 feed circuit of the footwell lamps. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 13

--

11

Replace the inoperative footwell lamp.

Did you complete the replacement?

Go to Step 13

--

12

Important: Perform the set up procedure for the Body Control Module.

Replace the Body Control Module. Refer to Body Control Module Replacement in Body Control Systems.

Did you complete the replacement?

Go to Step 13

--

13
  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 reset?

Go to Step 2

System OK