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.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Accessory Voltage

B1475

1

2

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  1. Partial or all relay controlled RAP functions inoperative depending on location of open.
  2. Relay RAP remains on past the timer limit after key out and will not turn off when a vehicle door is opened.

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. The RAP relay is internal to the BCM. 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. Radio RAP is controlled by a serial data message from the BCM using inputs from the driver door open switch. Refer to Retained Accessory Power (RAP) Description and Operation for more detail on RAP operation.

Diagnostic Aids

Window and radio RAP functions are separate RAP functions controlled by serial data messages and the specific module. These functions are not effected by the BCM internal RAP relay circuit.

Reference Information

Schematic Reference

Power Moding Schematics

Connector End View Reference

Power and Grounding Connector End Views

Electrical Information Reference

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

Circuit/System Verification

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

Radio RAP

  1. With all passenger doors closed, observe the courtesy lamps while opening and closing the driver door. The courtesy lamps should illuminate when the door is opened and turn off approximately 30 seconds after closing the door.
  2. If the courtesy lamp operation is incorrect from the drivers door, refer to Clearance Lamps Inoperative or Courtesy Lamps Inoperative .
  3. If courtesy lamp operation is correct, and the radio is the only RAP concern, replace the radio.

Relay RAP

  1. Ignition ON, observe the following scan tool parameters in the BCM while opening and closing each vehicle door. The reading should change appropriately between Door Closed/Door Ajar.
  2. •  Driver Door Ajar Sw.
    •  Left Rear Door Ajar Sw.
    •  Passenger Door Ajar Sw.
    •  Right Rear Door Ajar Sw.
    If any parameter does not change as specified, refer to Door Ajar Indicator Malfunction .
  3. Command the scan tool Accy/RAP Relay OFF. Attempt to operate any RAP relay controlled component within 5 seconds. The component should not operate.
  4. Command the scan tool Accy/RAP Relay ON. Attempt to operate any RAP relay controlled component within 5 seconds. The component should operate.
  5. Ignition ON, all doors closed. Observe the scan tool parameter Accy/RAP Relay Command. Ignition OFF, key removed, the reading should remain ON for approximately 10 minutes then change to OFF.
  6. If the parameter does not respond as specified, replace the BCM.

Circuit/System Testing

  1. Ignition OFF, disconnect harness connector X2 of the right I/P junction block.
  2. Connect a test lamp between the accessory voltage circuit terminal B3 (component side) and ground.
  3. Command the scan tool Accy/RAP Relay ON and OFF. the test lamp should cycle on and off as appropriate.
  4. If the test lamp is always ON, test the accessory voltage circuit for a short to voltage. If the circuit tests normal, replace the BCM.
    If the test lamp is always OFF, test the accessory voltage circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the BCM.
  5. If equipped with a sunroof, connect a test lamp between the accessory voltage circuit terminal B3 (harness side) and ground. The test lamp should not illuminate.
  6. If the test lamp illuminates, test the accessory voltage circuit for a short to voltage.
  7. If all circuits test normal, replace the BCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for module replacement, setup, and programming