Buick Regal: Seat Belt Indicator Malfunction - Passenger

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

1. Indicator will remain ON with seat belt buckled.
2. Indicator will illuminate only for the bulb check.
3. Indicator will not illuminate.
4. Indicator always ON.

Circuit/System Description

When an individual is sitting in the passenger seat the passenger presence sensor detects the individual.

A signal to the inflatable restraint sensing and diagnostic module indicates a person is in the passenger seat. The inflatable restraint sensing and diagnostic module will turn the passenger seat belt indicator on.

The passenger seat belt switch is a 2-wire switch wired to the inflatable restraint sensing and diagnostic module (SDM) using a signal circuit and a low reference circuit. When the seat belt is unbuckled the switch is closed, and when the seat belt is buckled the switch is open. The inflatable restraint sensing and diagnostic module sends the status of the passenger seat belt via a hard wire to the passenger air bag disable switch. After receiving the message, the passenger air bag disable switch controls the illumination of the passenger seat belt indicator.

Diagnostic Aids

Objects on the passenger seat can cause the passenger seat belt reminder to be commanded on.

Depending on the sensing technology used, a conductive object (computers, MP3 players, cell phones, diagnostic scan tool, wires, a hand, etc.) placed on the passenger seat may cause the passenger presence module to command the passenger air bag indicator ON and/or command the passenger seat belt indicator ON. The fasten seat belt chime will also sound.

Reference Information

Schematic Reference

Seat Belt Wiring Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Seat Belt System 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

1. Ignition ON.

2. Verify the passenger seat belt indicator turns ON and OFF when performing the Passenger Seat Belt Reminder Indicator On/Off Control Function with a scan tool.

• If the passenger seat belt indicator does not turn ON and OFF

Refer to Circuit/System Testing - Seat Belt Indicator Malfunction.

• Go to next step: If the passenger seat belt indicator turns ON and OFF

3. Verify the scan tool Passenger Seat Belt Status parameter changes between Buckled and Unbuckled when buckling and unbuckling the seat belt.

• If the parameter does not change between Buckled and Unbuckled when buckling and unbuckling the seat belt

Refer to Circuit/System Testing - Seat Belt Switch Malfunction.

• Go to next step: If the parameter changes between Buckled and Unbuckled when buckling and unbuckling the seat belt

4. All OK.

Circuit/System Testing

Seat Belt Switch Malfunction

NOTE: When removing connectors inspect for damage or corrosion.

Damage or corrosion in the following requires repair or replacement of the affected component/connector.

• B153P Seat Belt Buckle - Passenger
• Seat belt switch harness connector
• K36 Inflatable Restraint Sensing and Diagnostic Module
• Inflatable Restraint Sensing and Diagnostic Module harness connector

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B153 Seat Belt Buckle - Passenger. It may take up to 2 min for all vehicle systems to power down.

2. Test for less than 5 Ω between the low reference circuit terminal 1 and ground.

• If 5 Ω or greater

1. Disconnect the harness connector at the K36 Inflatable Restraint Sensing and Diagnostic Module.
2. Test for less than 2 Ω in each control circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K36 Inflatable Restraint Sensing and Diagnostic Module.

• Go to next step: If less than 5 Ω

3. Ignition ON.

4. Verify the scan tool Passenger Seat Belt Status parameter is Buckled.

• If the scan tool Passenger Seat Belt Status parameter does not display Buckled

1. Disconnect the harness connector at the K36 Inflatable Restraint Sensing and Diagnostic Module.
2. Test for infinite resistance between the signal circuit terminal 2 and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
   • If less infinite resistance, replace the K36 Inflatable Restraint Sensing and Diagnostic Module.

• Go to next step: If the scan tool Passenger Seat Belt Status parameter does display Buckled

5. Install a 3 A fused jumper wire between the signal circuit terminal 2 and the ground circuit terminal 1.

6. Verify the scan tool Passenger Seat Belt Status parameter is Unbuckled.

• If the scan tool Passenger Seat Belt Status parameter is not Unbuckled

1. Disconnect the harness connector at the K36 Inflatable Restraint Sensing and Diagnostic Module.
2. Ignition ON.
3. Test for less than 1 V between the signal circuit and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • Go to next step: If less than 1 V
4. Test for less than 2 Ω in each circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K36 Inflatable Restraint Sensing and Diagnostic Module.

• Go to next step: If the scan tool Passenger Seat Belt Status parameter does display Unbuckled

7. Ignition OFF, connect all harness connectors. Ignition ON.

8. Verify the scan tool Passenger Seat Belt Status parameter changes between Buckled and Unbuckled when buckling and unbuckling the seat belt.

• If the Passenger Seat Belt Status parameter is not Buckled and Unbuckled

Test or replace the B153 Seat Belt Buckle - Passenger.

• Go to next step: If the Passenger Seat Belt Status parameter does display Buckled and Unbuckled

9. All OK.

Seat Belt Indicator Malfunction

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the P14 Passenger Air Bag Disable Indicator. It may take up to 2 min for all vehicle systems to power down.

2. Test for less than 20 Ω between the ground circuit terminal 3 and ground.

• If 20 Ω or greater

1. Ignition OFF.
2. Test for less than 2 Ω in the ground circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, repair the open/high resistance in the ground connection.

• Go to next step: If less than 20 Ω

3. Test for 3-7 V between terminal 6 and ground when commanding the Passenger Seat Belt Reminder On with a scan tool.

• If greater then the specified range

1. Ignition OFF, disconnect the harness connector at the K36 Inflatable Restraint Sensing and Diagnostic Module. Ignition ON.
2. Test for less than 1 V between the control circuit and ground.
   • If 1V or greater, repair the short to voltage on the circuit.
   • If less than 1V, replace the K36 Inflatable Restraint Sensing and Diagnostic Module.

• If less then the specified range

1. Ignition OFF, disconnect the harness connector at the K36 Inflatable Restraint Sensing and Diagnostic Module.
2. Test for infinite resistance between the control circuit and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
3. Test for less than 2 Ω in the control circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K36 Inflatable Restraint Sensing and Diagnostic Module.

• Go to next step: If between 3-7 V

4. Test for less than 1 V between terminal 6 and ground when commanding the Passenger Seat Belt Reminder OFF with a scan tool.

• If greater than 1 V

Replace the K36 Inflatable Restraint Sensing and Diagnostic Module

• Go to next step: If less than 1 V

5. Test or replace the P14 Passenger Air Bag Disable Indicator.

Component Testing

1. Ignition OFF, disconnect the harness connector at the B153 Seat Belt Buckle - Passenger.

2. Buckle the passenger seat belt.

3. Test for infinite resistance between the signal circuit terminal 2 and the low reference circuit terminal 1.

• If less than infinite resistance

Replace the B153 Seat Belt Buckle - Passenger.

• Go to next step: If infinite resistance

4. B88 seat belt switch in the unbuckled position.

5. Test for less than 2 Ω between the signal circuit terminal 2 and the low reference terminal 1.

• If 2 Ω or greater

Replace the B153 Seat Belt Buckle - Passenger.

• Go to next step: If less than 2 Ω

6. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair

• Front Seat Belt Buckle Replacement
• Refer to Instrument Panel Assembly Replacement for S48C Multifunction Switch 1 - Instrument Panel replacement
• Control Module References for inflatable restraint sensing and diagnostic module replacement, programming and setup

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