Circuit Description
The Body Control Module (BCM) controls the backup lamp relay. The BCM grounds the backup lamps relay control circuit which in turns energizes the backup lamp relay.
Conditions for Running the DTC
| • | The transaxle must be in the reverse position. |
| • | The Ignition switch must be in the RUN position. |
| • | The emergency vehicle interior lamp switch is not enabled. |
Conditions for Setting the DTC
| • | The BCM detects a short to battery in the backup lamp relay control circuit when the BCM tries to energize the backup lamp relay. |
| • | The condition above must be present for more than 0.3 seconds. |
Action Taken When the DTC Sets
| • | The BCM stores DTC B2553 in memory. |
| • | The SERVICE VEHICLE SOON telltale illuminates. |
Conditions for Clearing the DTC
| • | The BCM no longer detects a short to battery in the backup lamp relay control circuit. |
| • | A history DTC B2553 will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present. |
Diagnostic Aids
| • | If the DTC B2553 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 backup lamp relay control circuit |
| - | The backup lamp relay coil is intermittently shorted to the battery internally |
| - | The BCM is intermittently shorted to the battery internally |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
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Listen for an audible click when the backup lamp relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
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Tests for voltage at the coil side of the backup lamp relay. The R/CMPT fuse supplies power to the coil side of the backup lamp relay.
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Verifies that the Body Control Module (BCM) is providing ground to the backup lamp relay.
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Tests if ground is constantly being applied to the backup lamp relay.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Lighting System Diagnostic System Check? | -- | Go to Step 2 | |
Does the backup lamp relay turn ON and OFF with each command? | -- | Go to Diagnostic Aids | Go to Step 3 | |
Does the test lamp illuminate? | -- | Go to Step 4 | Go to Step 10 | |
Does the test lamp turn ON and OFF with each command? | -- | Go to Step 8 | Go to Step 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 backup lamp relay for a short to voltage 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 backup 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 backup 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 BCM. 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 coil side feed circuit of the backup lamp relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 13 | -- |
11 | Replace the backup lamp relay. Did you complete the replacement? | -- | Go to Step 13 | -- |
12 |
Important: Perform the setup procedure for the body control module. Replace the BCM. Refer to Body Control Module Replacement in Body Control System. Did you complete the replacement? | -- | Go to Step 13 | -- |
13 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
