Circuit Description
The BCM interfaces with the vehicle's power distribution system through the RAP#1 relay. The RAP#1 relay allows the BCM to control the application of power to the feed accessory circuits.
When the ignition switch turns from ON/RUN to LOCK or OFF, with all of the vehicle doors closed, the BCM leaves the RAP#1 relay energized for 20 minutes, or until any vehicle door opens and the BCM detects a ground signal in one of the door ajar circuits.
Conditions for Setting the DTC
| • | The BCM detects no voltage at the RAP#1 relay control circuit when the BCM has not grounded the circuit. |
| • | The conditions above must be present for more than 300 milliseconds. |
Action Taken When the DTC Sets
| • | The BCM stores DTC B1477 in memory. |
| • | The circuits powered by the RAP#1 relay remain powered at all times if the relay control circuit is shorted to ground. |
| • | The circuits powered by the RAP#1 relay will never be powered if the relay control circuit is open. |
Conditions for Clearing the DTC
| • | The correct voltage is present at the RAP#1 relay control circuit as detected by the BCM. |
| • | A history DTC B1477 will clear after the modules ignition cycle counter reaches the reset threshold, without a repeat of the malfunction. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Listen for an audible click when the RAP#1 relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
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This step tests for voltage at the coil side of the RAP#1 relay. The RAP#1 fuse in the Fuse Block Underhood, supplies power to the coil side of the RAP#1 relay.
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This step verifies that the Body Control Module (BCM) is providing ground to the RAP#1 relay.
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This step tests if ground is constantly being applied to the RAP#1 relay.
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Retained Accessory Power (RAP) Diagnostic System Check? | Go to Step 2 | |
Does the RAP#1 Relay turn ON and OFF with each command? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | 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 RAP#1 relay for 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 RAP#1 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 RAP#1 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 Body Control Module (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 | Test the relay coil supply circuit of the RAP#1 relay for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 13 | -- |
11 | Replace the RAP#1 relay. Did you complete the repair? | Go to Step 13 | -- |
12 |
Important: Perform the set up procedure for the BCM. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System. Replace the BCM. Refer to Body Control Module Replacement in Body Control System. Did you complete the repair? | Go to Step 13 | -- |
13 |
Does the DTC reset? | Go to Step 2 | System OK |
