GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2006 🢒 Lucerne 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Retained Accessory Power Malfunction

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The retained accessory power (RAP) relay is located in the rear fuse block. The relay control is from the body control module (BCM). The relay switched output feeds the RAP MISC fuse 10 A and the PWR/WINDW circuit breaker both within the I/P fuse block. The RAP MISC fuse supplies voltage to the shift lock control solenoid, inside rearview mirror, and if equipped the sunroof.

Diagnostic Aids
    • A short to ground in the accessory voltage circuit should cause an open fuse or circuit breaker causing only part of the RAP functions to be inoperative.
    • An open in the in the either accessory voltage circuit will cause inoperative conditions effecting only part of the RAP functions to be inoperative.
    • A short to voltage on the relay control or relay output circuits would cause the RAP function to remain on past the designated time.
    • An stuck relay switch could cause a RAP always on, or a RAP inoperative condition.

Reference Information

Schematic Reference

Power Distribution Schematics

Connector End View Reference

Master Electrical Component List

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Circuit/System Testing

Important: If any door open switch input to the BCM is reporting a door open when it is not the RAP function will not operate after the key is turned off or removed and the courtesy lamps will remain on longer than 30 seconds after exiting the vehicle and closing all doors. Before continuing diagnosis, ensure that the courtesy lamps turn off properly after closing all doors. If courtesy lamps remain on, refer to Symptoms - Lighting Systems .

  1. Ignition OFF, remove the RAP relay.
  2. Test for less than 1 ohm of resistance between the relay coil ground circuit and ground.
    3. ⇒If greater than 1 ohm, repair the ground circuit for an open/high resistance.
  3. Connect a test lamp between the RAP relay control circuit and ground. Close all vehicle doors.
  4. Observe the test lamp, cycle the ignition key to the RUN position and back to the OFF position, wait 10 seconds, open the driver door. The test lamp should turn ON when key is in RUN, and remain on until the driver door is opened.
    5. ⇒If the test lamp remains ON all the time, test for a short to voltage on the relay coil control circuit. If the circuit tests normal, replace the BCM.
    ⇒If the test lamp remains OFF all the time, test for a short to ground or open/high resistance on the relay coil control circuit. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the RAP relay.

Component Testing

Relay Test

  1. Ignition OFF, disconnect the RAP relay.
  2. Test for 70-110 ohms of resistance between terminals 85 and 86.
    3. ⇒If the resistance is not within the specified range, replace the relay.
  3. Test for infinite resistance between the following terminals:
    4. • 30 and 86
    • 30 and 87
    • 30 and 85
    • 85 and 87
    ⇒If less than infinite, replace the relay.
  4. Install a 20-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 5 ohms of resistance between terminals 30 and 87.
    5. ⇒If greater than 5 ohms, replace the relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for module replacement, setup, and programming