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For 1990-2009 cars only
Makes 🢒 Buick 🢒 2009 🢒 LaCrosse 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic 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.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Accessory (Driver window switch)

2

2

1*

--

Accessory (Passenger window switch)

2

2

1*

--

Accessory (Sunroof module w/CF5)

2

2

1*

--

RAP Relay Control

1

B1475

B1475

--

  1. RAP remains on past the timer limit after key out and will not turn off when a vehicle door is opened.
  2. Only the individual RAP component will be inoperative.

* A short to voltage will back feed and supply voltage to all relay controlled components.

Circuit/System Description

The retained accessory power (RAP) system allows specific vehicle functions to operate after the ignition is turned OFF for a predetermined time. Relay RAP is controlled by the BCM using inputs from the door ajar switches to determine control of the relay when the ignition is turned OFF. Serial data RAP is controlled by a serial data message from the BCM. Refer to Retained Accessory Power (RAP) Description and Operation for more detail on subsystems using RAP. The RAP relay is located in the I/P fuse block. The relay switched output feeds the following:

    • Power window circuit breaker
    • Sunroof fuse (CF5)

Diagnostic Aids
    • The radio and window RAP function are separate RAP functions controlled by serial data and the specific module. These functions are not effected by the BCM RAP relay circuits.
    • A short to ground or open/high resistance in the RAP relay switched voltage circuits will cause only part of the RAP functions to be inoperative. Diagnose these symptoms within the respective system sections.
    • A short to voltage on the RAP relay control or switched voltage circuits would cause the relay controlled RAP functions to remain on past the designated time.
    • If all relay controlled RAP functions are inoperative (radio RAP functions) and DTC B1475 is not set, test or replace the RAP relay.
    • If all RAP functions are inoperative (including radio) and DTC B1475 is not set, replace the BCM.

Reference Information

Schematic Reference

Power Moding Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Retained Accessory Power (RAP) Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for Scan Tool Information

Circuit/System Verification

Important: Battery voltage must remain above 9.6 V for RAP to operate properly.

  1. Ignition ON, observe the scan tool BCM parameters listed below while opening and closing each vehicle door. The reading should change appropriately between Door Closed/Ajar for the front door ajar switches, and between Closed/Ajar for the rear door ajar switches.

    2. Module/Parameter

    •  Left Rear Door Ajar Sw.
    •  LF Door Ajar Switch
    • RF Door Ajar Switch
    • Right Rear Door Ajar Sw.
    ⇒If any parameter does not change as specified, refer to Door Ajar Indicator Malfunction .
  2. Command the scan tool Retained Accessory Power OFF. Attempt to operate any RAP relay controlled component within 5 seconds. The component should not operate.
  3. Command the scan tool Retained Accessory Power ON. Attempt to operate any RAP relay controlled component within 5 seconds. The component should operate.
  4. Ignition ON, all doors closed. Observe the scan tool parameter RAP Relay. Ignition OFF, key removed, the reading should be ON for approximately 10 minutes then change to OFF.
    5. ⇒If the parameter does not respond as specified, replace the BCM.

Circuit/System Testing
  1. Ignition OFF, disconnect the RAP Relay.
  2. With the driver door open, verify that a test lamp does not illuminate between the rap relay control circuit terminal N1 and B+.
    3. ⇒If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.
  3. Verify that a test lamp does not illuminate between the rap relay accessory circuit terminal M1 and ground.

    4. Important: The accessory circuit supplies voltage to multiple components from the RAP relay. A short to voltage on any of the circuits will supply voltage to all components.

    ⇒If the test lamp illuminates, test the accessory circuit for a short to voltage.
  4. 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 not the specified value, 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 5.0 ohms of resistance between terminals 30 and 87.
    5. ⇒If greater than specified, replace the relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

    •  Relay Replacement
    •  Control Module References for module replacement, setup, and programming