Circuit Description
The backup lamp relay is controlled by the body control module (BCM). The BCM provides ground to the backup lamp relay control circuit in order to turn ON the backup lamp relay. When the backup lamp relay control circuit opens, becomes shorted to voltage, or becomes shorted to ground without being commanded ON by the BCM, DTC B2545 is set.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2545 Backup Lamps Circuit
Conditions for Running the DTC
The ignition switch is in the ON position.
Conditions for Setting the DTC
| • | B2545.01 will set if there is a short to voltage in the backup lamp relay control circuit. |
| • | B2545.06 will set if there is an open or short to ground in the backup lamp relay control circuit. |
Action Taken When the DTC Sets
| • | DTC B2545 is stored in the BCM memory. |
| • | If the backup lamp relay control circuit is shorted to ground, the backup lamps are always ON when the ignition is ON. |
| • | If the backup lamp relay control circuit is open, the backup lamps are inoperative. |
Conditions for Clearing the DTC
| • | The conditions for setting the DTC are no longer present. |
| • | A history DTC clears after 100 malfunction free ignition cycles. |
| • | The BCM receives the clear code command from the scan tool. |
Diagnostic Aids
| • | The backup lamps will only illuminate under the following conditions: |
| - | The ignition is ON. |
| - | The gear selector is in the reverse position. |
| • | If the DTC is a history DTC, the problem may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Fog Lights Schematics Connector End View Reference: Master Electrical Component List | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
Does the backup lamp relay state change with each command? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 | |
3 | Are the backup lamps illuminated? | Go to Step 6 | Go to Step 4 |
4 |
Does the test lamp illuminate? | Go to Step 5 | Go to Step 7 |
5 | Connect a test lamp between the backup lamp relay control circuit and the backup lamp relay control side battery positive voltage circuit. Does the test lamp illuminate? | Go to Step 8 | Go to Step 10 |
6 | Test the fog lamp relay control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 9 |
7 | Test the backup lamp relay control circuit for an open, high resistance, or short to voltage. Refer to Circuit Testing and Wiring Repairs . 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 . 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 (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 12 |
10 | Repair an open, high resistance, or short to ground in the backup lamp relay control side battery positive voltage circuit. Refer to Wiring Repairs and Connector Repairs . Did you complete the repair? | Go to Step 13 | -- |
11 | Replace the backup lamp relay. Refer to Relay Replacement. Did you complete the replacement? | Go to Step 13 | -- |
12 | Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 13 | -- |
13 |
Does the DTC reset? | Go to Step 2 | System OK |
