GM Service Manual Online
For 1990-2009 cars only

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.

DTC Descriptor

DTC B1475: Retained Accessory Power Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

B+

B1475

B1475

--

Rap Relay Control

--

B1475

B1475

Circuit Description

The body control module (BCM) controls various accessories through the retained accessory power (RAP) relay circuit. When the ignition switch is in either the ACC or the ON position, the BCM grounds the RAP relay control circuit, energizing the RAP relay. When the RAP relay is energized, it supplies a B+ to the various accessories.

When the ignition switch turns from ON or ACC to OFF, with all of the vehicle doors closed, the BCM keeps the relay energized for 10 minutes, or until any vehicle door opens.

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 voltage in the RAP relay control circuit when the BCM is trying to energize the relay.
    • The BCM detects that the RAP relay control circuit is open.
    • The condition above must be present for more than 1 second.

Action Taken When the DTC Sets

    • The BCM stores DTC B1475 in memory.
    • The devices powered by the RAP relay 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.

Reference Information

Schematic Reference

Power Distribution Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Retained Accessory Power 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

Ignition ON, command the retained accessory power (RAP relay) ON and OFF with a scan tool. Feel/listen for the operation of the RAP relay.

Circuit/System Testing

  1. Ignition OFF, disconnect the RAP relay.
  2. Test for less than 5 Ω between the ground circuit terminal N1 and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Connect a test lamp between the relay control circuit terminal M3 and ground.
  5. Cycle the ignition ON and OFF. The test lamp should turn ON and OFF when changing ignition switch positions.
  6. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
    If the test lamp is always OFF, test the control circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the BCM.
  7. If all circuits test normal, test or replace the RAP relay.

Component Testing

  1. Ignition OFF, disconnect the RAP relay.
  2. Test for 70 - 150 Ω between the B+ terminal 85 and the ground terminal 86 of the relay.
  3. If not within the specified range, replace the relay.
  4. Test for infinite resistance between the following terminals:
  5. • 30 and 86
    • 30 and 87
    • 30 and 85
    • 85 and 87
    If not the specified value, replace the relay.
  6. Install a 3 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 Ω between terminals 30 and 87.
  7. If greater than the specified range, replace the relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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