GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2003 🢒 Grand Prix 🢒 Body and Accessories 🢒 Lighting Systems 🢒 DTC 002

Circuit Description

The body control module (BCM) controls the inadvertent load (battery rundown) protection feature. The BCM de-energizes the courtesy lights supply voltage circuit ten minutes after the ignition switch has been turned from the ACC position or the RUN position to the LOCK position or the OFF position.

The BCM restores power to the courtesy lights supply voltage circuit when the following actions occur:

    • The ignition switch is turned from the LOCK position or the OFF position to the ACC position or the RUN position.
    • The key is removed from the ignition.
    • Any vehicle door is opened.
    • The instrument panel dimmer switch is turned to the DOME position.
    • Any interior courtesy light connected to the courtesy lights supply voltage circuit turned on.
    • The BCM receives a message to unlock the doors from the remote control door lock receiver (BCM type 3 or type 4 only).
    • A door is unlocked using a key (BCM type 4 only).

The inadvertent load (battery rundown) protection feature is mileage-sensitive. Vehicles with less than 15 total driven miles (24 kilometers) have a time-out of 162-198 seconds instead of 10 minutes.

Conditions for Setting the DTC

The BCM detects a short to battery positive voltage or ground in the courtesy lights supply voltage circuit.

Action Taken When the DTC Sets
    • The BCM sets the Diagnostic Trouble Code (DTC) 2.
    • The inadvertent load (battery rundown) protection feature is disabled when the courtesy lights supply voltage circuit is shorted to battery positive voltage.
    • The interior courtesy lights do not turn on when the courtesy lights supply voltage circuit shorted to ground.

Conditions for Clearing the MIL/DTC
    • A short to battery positive voltage or ground in the courtesy lights supply voltage circuits no longer present.
    • After you complete the repairs, refer to On-Board Diagnostic Features in order to clear the DTC.

Diagnostic Aids
    • Inspect for a short to battery positive voltage in the courtesy lights supply voltage circuit.
    • Inspect for a short to ground in the courtesy lights supply voltage circuit.

Test Description

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

  1. Always perform the lighting diagnostic system check before attempting to diagnose the DTC.

    2.

  2. This step performs the BCM Input/Output test. This test energizes and de-energizes the courtesy lights supply voltage circuit. If the courtesy lights turn off during this test the courtesy lights supply voltage circuit is not shorted to battery positive voltage or ground.

    3.

  3. Tests the courtesy lights supply voltage circuit of the BCM for a short to battery positive voltage.

    4.

  4. Tests the courtesy lights supply voltage circuit of the interior lamps override switch for a short to battery positive voltage.

Power Output Circuit to Courtesy Lights Shorted to Battery Positive Voltage or Ground

Step

Action

Value(s)

Yes

No

Schematic Reference: Interior Lights Schematics

Connector End View Reference: Power and Grounding Connector End Views in Wiring Systems

1

Was the BCM Diagnostic System check performed?

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Go to Step 2

Go to Diagnostic System Check - Body Control System in Body Control Systems

2

Perform the BCM Input/Output test. Refer to Diagnostic Starting Point - Body Control System .

Do all lights connected to courtesy lights supply voltage circuit turn off when the BCM Input/Output performs test 1 and turn on when performing test 2?

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Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the body control module (BCM) connector C1
  3. Turn the ignition switch to the RUN position.
  4. Measure the voltage between the BCM harness connector C1 courtesy lamps supply voltage circuit and ground.

Is the voltage less than the specified value?

2 V

Go to Step 4

Go to Step 5

4

  1. Make sure all reading lights, sunshade illuminated mirror lamps, IP compartment lamp, and rear compartment courtesy lamp are all off.
  2. Use a DMM in order to measure the resistance between the BCM harness connector C1 protected battery positive voltage output courtesy lights circuit and ground.

Is the resistance equal to the specified value?

OL (infinite)

Go to Step 7

Go to Step 6

5

Repair the short to voltage in the courtesy lamps supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 8

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6

Repair the short to ground in courtesy lamps supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 8

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7

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

Did you complete the repair?

--

Go to Step 8

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8
  1. Turn the ignition switch to the OFF position.
  2. Reinstall connectors/components removed.
  3. Open any vehicle door for 10 seconds.
  4. Close all vehicle doors.
  5. Remove the MALL PGM Fuse.
  6. Turn the ignition switch to the ACC position. (The BCM sounds the chime a number of times equivalent to the BCM type installed on the vehicle).
  7. Within one second, turn the ignition switch from the ACC position, to the OFF position, then back to the ACC position. (The BCM sounds any DTCs stored).

Are there any BCM DTCs present?

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Go to Diagnostic System Check - Body Control System

System OK