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For 1990-2009 cars only
Makes 🢒 Buick 🢒 1999 🢒 Regal 🢒 Body and Accessories 🢒 Body Control System 🢒 DTC B2553 Backup Lamps Control Circuit High

Object Number: 385123 Size: SF

Circuit Description

The backup lamp circuit is completed by the BCM when it receives a signal from the PCM that the vehicle is in reverse. The BCM momentarily grounds circuit 38, energizing the backup lamp relay.

Conditions for Setting the DTC
    • The BCM detects a short to B+ in circuit 38 while attempting to ground circuit 38.
    • The BCM tests for a short to B+ in circuit 38 only when attempting to turn on the backup lamps.
        All conditions must be present for more than 0.15 seconds.

Action Taken When the DTC Sets
    • The BCM stores DTC B2553 in memory.
    • The BCM turns off its output to the backup lamp relay.

Conditions for Clearing the DTC
    • When the ignition switch is cycled form off to on, the current DTC is cleared. If the fault is present at the next backup lamp activation, this DTC sets as current.
    • A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
    • Using a scan tool.

Diagnostic Aids
    • The following conditions may cause an intermittent malfunction to occur:
       - An intermittent short to B+ in circuit 38.
       - The BCM is shorted to B+ internally.
       - The backup lamp relay coil is shorted to B+ internally.
    • If the DTC is a history DTC, the problem may be intermittent. Try performing the tests shown while moving wiring and connectors, this can often cause the malfunction to reappear.
    • DTC P1626 will set in the Powertrain Control Module (PCM) when the ignition switch is on with the Body Control module (BCM) disconnected. When BCM diagnostics and repairs are completed, refer to Engine Controls for additional information on PCM related DTCs.

Test Description

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

  1. This step checks for a short to B+ in circuit 38.

    2.

  2. This step determines whether circuit 38 has a short to B+ or the BCM is faulty.

    3.

  3. This step checks BCM DTC B2553 and checks for BCM DTC B2553 to set again.

Step

Action

Value(s)

Yes

No

1

Was the BCM Diagnostic System check performed?

--

Go to Step 2

Go to Diagnostic System Check - Body Control System

2

  1. Disconnect the backup lamp relay connector.
  2. Using a test light, connect between the backup lamp relay harness connector terminal A1 and ground.

Is the test light on?

--

Go to Step 3

Go to Step 4

3

  1. Leave the test light in the same location from the previous step.
  2. Turn the ignition switch the OFF position.
  3. Disconnect the BCM connectors.
  4. Turn the ignition switch the ON position.

Is the test light on?

--

Go to Step 5

Go to Step 6

4

Replace the backup lamp relay.

Is the repair complete?

--

Go to Step 9

--

5

Repair short to B+ in circuit 38.

Is the repair complete?

--

Go to Step 9

--

6

  1. Turn the ignition switch to the OFF position.
  2. Reinstall connectors/components removed.
  3. Turn the ignition switch to the ON position.
  4. Clear BCM DTCs. Refer to Clearing DTCs Clearing DTCs for more information.
  5. Put the trans range switch in reverse.
  6. Check for BCM DTCs. Refer to Diagnostic Trouble Code (DTC) Displaying Displaying DTCs for more information.

Does BCM DTC B2553 reset as a current DTC?

--

Go to Step 7

Go to Step 8

7
  1. Replace the BCM. Refer to Body Control Module Replacement Body Control Module Replacement for more information.
  2. After replacing the BCM, perform the Setup New BCM procedure. Refer to Body Control Module (BCM) Programming/RPO Configuration BCM Programming/RPO Configuration for more information.

Is the repair complete?

--

Go to Step 9

--

8

The malfunction is not present at this time. Refer to Diagnostic Aids for additional information regarding DTC 2553.

Is the repair complete?

--

Go to Step 9

9
  1. Turn the ignition switch to the OFF position
  2. Reinstall connectors/components removed.
  3. Turn the ignition switch to the ON position.
  4. Clear BCM DTCs. Refer to Clearing DTCs for more information.
  5. Check for BCM current DTCs. Refer to Diagnostic Trouble Code (DTC) Displaying for more information.

Are there any BCM current DTCs set?

--

Go to Diagnostic System Check - Body Control System

System OK