Circuit Description
The body control module (BCM) controls the sunroof motor operation through the retained accessory power (RAP) supply voltage circuit. When the ignition switch is in either the ACC or the ON position, the BCM provides battery voltage to the RAP supply voltage circuit. When the ignition switch turns from ON or ACC to OFF, with all of the vehicle doors closed, the BCM still provides battery voltage to the circuit for 10 minutes, or until any vehicle door opens.
DTC Descriptors
This diagnostic procedure supports the following DTC:
DTC B1477 Retained Accessory Power Circuit Low
Conditions for Running the DTC
The system voltage must be between 9-16 volts.
Conditions for Setting the DTC
| • | The BCM detects a short to ground in the RAP supply voltage circuit when the BCM is trying to energize the circuit. |
| • | The condition above must be present for more than 1 second. |
Action Taken When the DTC Sets
| • | The BCM stores DTC B1477 in memory. |
| • | The sunroof will not operate. |
Conditions for Clearing the DTC
| • | A current DTC clears when the malfunction is no longer present. |
| • | A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Power Moding Schematics Connector End View Reference: Master Electrical Component List | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
Does the DTC B1477 still set as current? | Go to Step 3 | Go to Step 4 |
3 | Test the retained accessory power (RAP) supply voltage circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 8 | Go to Step 5 |
4 | Inspect for poor connections at the sunroof motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 8 | Go to Step 6 |
5 | Inspect for poor connections at the harness connector of the BCM . Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 8 | Go to Step 7 |
6 | Replace the sunroof motor. Refer to Control Module References for replacement, setup, and programming, if applicable. Did you complete the replacement? | Go to Step 8 | -- |
7 | Replace the BCM . Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 8 | -- |
8 |
Does the DTC reset? | Go to Step 1 | System OK |
