GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2008 🢒 XLR 🢒 Body Systems 🢒 Vehicle Access 🢒 Fuel Filler Door Release Inoperative

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

Fuel Door Release Relay B+

1

1

1

--

Fuel Door Release Actuator Control

1

1

1

--

Fuel Door Relay Control

1

1

1

--

Fuel Door Release Actuator Ground

--

1

--

--

Fuel Door Release Switch Ground

--

1

--

--

1. Fuel Door Release Malfunction

Circuit/System Description

The FUEL DR relay switch and coil terminals are supplied with battery voltage at all times via the DR CNTRLS circuit breaker. When the fuel door release switch is activated, ground is applied to the coil side of the FUEL DR relay. This energizes the coil causing the switch contacts to close. With the switch contacts closed, battery voltage is supplied to the fuel door release actuator, releasing the fuel door.

Reference Information

Schematic Reference

Release Systems Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Fuel Fill Door Description and Operation

Electrical Information Reference

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

Circuit/System Verification

Command the fuel door to release by pressing the fuel door release switch. The fuel door release actuator should release the fuel door.

Circuit/System Testing
  1. Ignition OFF, disconnect the FUEL DR relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal A5 and ground.
    3. ⇒If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal A2 and ground.
    4. ⇒If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal A3 and ground.
    5. ⇒If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  5. Disconnect the harness connector at the fuel door release actuator.
  6. Ignition OFF, test for less than 5 ohms between the ground circuit terminal B and ground.
    7. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the fuel door release actuator.
  8. Ignition ON, connect a 30A fused jumper wire between the B+ circuit terminal A3 and the control circuit terminal A5. Verify the fuel door release actuator is activated.
    9. ⇒If the fuel door release actuator does not activate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the fuel door release actuator.
  9. Disconnect the harness connector at the fuel door release switch.
  10. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal A.
    11. ⇒If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  11. Connect the harness connector at the fuel door release switch.
  12. Connect a test lamp between the B+ circuit terminal D4 and the control circuit terminal C6.
  13. Command the FUEL DR relay ON and OFF by pressing and releasing the fuel door release switch. The test lamp should illuminate with each press of the fuel door release switch.
    14. ⇒If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, test or replace the fuel door release switch.
    ⇒If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, test or replace the fuel door release switch.
  14. If all circuits test normal, test or replace the FUEL DR relay.

Component Testing

Relay Test

  1. Ignition OFF, disconnect the FUEL DR relay.
  2. Test for 60-180 ohms between terminals 85 and 86.
    3. ⇒If 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 25-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 2 ohms between terminals 30 and 87.
    5. ⇒If greater than the specified range, replace the relay.

Fuel Door Release Actuator

  1. Ignition OFF, disconnect the harness connector at the fuel door release actuator.
  2. Install a 30A fused jumper wire between the control terminal A and 12 volts. Momentarily install a jumper wire between the ground terminal B and ground. Verify the fuel door release actuator activates.
    3. ⇒If the actuator does not perform as specified, replace the fuel door release actuator.

Fuel Door Release Switch

  1. Ignition OFF, disconnect the harness connector at the fuel door release switch.
  2. Test for infinite resistance between the control terminal D and the ground terminal A with the switch in the open position.
    3. ⇒If not the specified value, replace the fuel door release switch.
  3. Test for less than 2 ohms between the control terminal D and the ground terminal A with the switch in the closed position.
    4. ⇒If greater than the specified range, replace the fuel door release switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Relay Replacement
    •  Fuel Tank Filler Door Lock Actuator Replacement
    •  Fuel Tank Filler Door Lock Release Switch Replacement