B0127-12

B0127-12-FRONT DRIVER BUCKLE SWITCH - CIRCUIT SHORT TO BATTERY

Special Tools:

For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

When powered, the Occupant Restraint Controller (ORC) sends a test current across the Driver Seat Belt Buckle Switch circuits to verify the integrity of the switch and wiring. The front seat belt switches cannot be adjusted or repaired and, if ineffective or damaged, the entire front seat belt buckle-half unit must be replaced. The seatbelt reminder lamp will display in the instrument cluster for this fault. The ORC obtains the buckle switch status of the driver and front passenger, as well as the status of the front passenger seat occupant detection mat. If the driver or front passenger is unbelted, the ORC sends a message to the IPC over the CAN-B bus to turn on the seatbelt reminder light. The light remains on until the front seatbelts are fastened. An audible alert triggers within 60 seconds of vehicle speed over 5 mph. The seatbelt reminder light remains illuminated until the front belts are fastened. The seatbelt buckle switch consists of a Hall-effect sensor assembly. The ORC determines the status of the seatbelt (buckled/unbuckled) based on the amount of current drawn by the sensor. When the seatbelt is unbuckled, the sensor draws a current of approximately 6.5 mA. When the seat is buckled, the sensor draws a current of approximately 15 mA.

- When Monitored:
The ORC monitors the status of the seat belt switch circuits at power up and every 60 ms thereafter while the ignition is in on.

- Set Condition:
This DTC sets when the ORC detects the seat belt switch circuits have become shorted to voltage for more than 2.5 seconds. This DTC transitions from active to stored when the module sees a recovery from the shorted to voltage condition for greater than five seconds.

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Restraints System Pre-Diagnostic Procedure.

1. VERIFY ACTIVE DTC

NOTE: Make sure the battery is fully charged.

1. Turn the ignition on.
2. With the scan tool, read ORC DTC.

Does the scan tool display active B0127-12-FRONT DRIVER BUCKLE SWITCH - CIRCUIT SHORT TO BATTERY DTC?

Yes

- Go To 2

No

- Perform the RESTRAINTS SYSTEM INTERMITTENT TEST. Restraints System Intermittent Condition Test.

2. DRIVER SEAT BELT BUCKLE SWITCH SHORTED TO VOLTAGE

WARNING: Turn the ignition off, disconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.

1. Disconnect the Driver Seat Belt Buckle Switch harness connector.

NOTE: Check connectors - Clean and repair as necessary.

WARNING: Turn the ignition on, then reconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.

2. Measure the voltage on the (R57) Driver Seat Belt Buckle Switch Sense circuit between the appropriate terminal of the Driver Seat Belt Buckle Switch harness connector and ground.
3. Measure the voltage on the (R59) Driver Seat Belt Buckle Switch Ground circuit between the appropriate terminal of the Driver Seat Belt Buckle Switch harness connector and ground.

Is there a short to voltage on any of these circuits?

Yes

- WARNING: Turn the ignition off, disconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.

- Repair the (R57, R59) Driver Seat Belt Buckle Switch circuit for a short to voltage.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test.

No

- Go To 3

3. (R57) DRIVER SEAT BELT BUCKLE SWITCH SENSE CIRCUIT AND (R59) DRIVER SEAT BELT BUCKLE SWITCH GROUND CIRCUIT FOR AN OPEN

3. Connect the SRS Load Tool 56 Way ACM Adapter (8443-25) to the ORC C2 harness connector.
4. Measure the resistance of the (R57) Driver Seat Belt Buckle Switch Sense circuit between the appropriate terminal of the Driver Seat Belt Buckle Switch harness connector and the appropriate terminal of the SRS Load Tool 56 Way ACM Adapter (8443-25).
5. Measure the resistance of the (R59) Driver Seat Belt Buckle Switch Ground circuit between the appropriate terminal of the Driver Seat Belt Buckle Switch harness connector and the appropriate terminal of the SRS Load Tool 56 Way ACM Adapter (8443-25).

Is the resistance greater than 1.0 Ohm on any of these circuits?

Yes

- Repair the (R57, R59) Driver Seat Belt Buckle Switch circuits for an open.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test.

No

- Go To 4

4. CHECK OPERATION OF THE DRIVER SEAT BELT BUCKLE SWITCH

WARNING: Turn the ignition off, disconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.

1. Replace the Driver Seat Belt Buckle Switch. Procedures.
2. Reconnect the vehicle body harness connector to the Driver Seat Belt Buckle Switch.
3. Remove any special tools or jumper wires and reconnect all previously disconnected components - except the Battery.

WARNING: Turn the ignition on, then reconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.

4. Connect the scan tool to the Data Link Connector - use the most current software available.
5. Use the scan tool and erase the stored DTCs.
6. Turn the Ignition OFF, and wait 15 seconds before turning the Ignition ON.
7. Wait one minute, and read active DTCs and if there are none present read the stored DTCs.

Does the scan tool display active B0127-12-FRONT DRIVER BUCKLE SWITCH - CIRCUIT SHORT TO BATTERY DTC?

Yes

- WARNING: Turn the ignition off, disconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.

- WARNING: If the Occupant Restraint Controller (ORC) is dropped at any time, it must be replaced. Failure to follow these instructions may result in possible serious or fatal injury.

- Replace the Occupant Restrain Controller (ORC). Occupant Restraint Controller - Removal.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test.

No

- Repair is complete.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test.