For 1990-2009 cars

### 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 | High Resistance | Open | Short to Voltage | Signal Performance
--- | --- | --- | --- | --- | ---
Left Front Seat Belt Sensor Signal | B0072 02, B0072 06, B0072 0B, 1 | B0072 04, B0072 05, B0072 06, B0072 0C, 2 | B0072 04, B0072 05, B0072 06, 2 | B0072 01, B0072 05, 2 | B0072 08
Left Front Seat Belt Sensor Low Reference | -- | B0072 04, B0072 05, B0072 06, B0072 0C, 2 | B0072 04, B0072 05, B0072 06, 2 | 2 | B0072 08
Right Front Seat Belt Sensor Signal | B0073 02, B0073 06, B0073 0B, 1 | B0073 04, B0073 05, B0073 06, B0073 0C, 2 | B0073 04, B0073 05, B0073 06, 2 | B0073 01, B0073 05, 2 | B0073 08
Right Front Seat Belt Sensor Low Reference | -- | B0073 04, B0073 05, B0073 06, B0073 0C, 2 | B0073 04, B0073 05, B0073 06, 2 | 2 | B0073 08
Left Rear Seat Belt Sensor Signal | B0075 02, B0075 06, B0075 0B | B0075 04, B0075 05, B0075 06, B0075 0C | B0075 04, B0075 05, B0075 06 | B0075 01, B0075 05 | B0075 08
Left Rear Seat Belt Sensor Low Reference | -- | B0075 04, B0075 05, B0075 06, B0075 0C | B0075 04, B0075 05, B0075 06 | -- | B0075 08
Right Rear Seat Belt Sensor Signal | B0076 02, B0076 06, B0076 0B | B0076 04, B0076 05, B0076 06, B0076 0C | B0076 04, B0076 05, B0076 06 | B0076 01, B0076 05 | B0076 08
Right Rear Seat Belt Sensor Low Reference | -- | B0076 04, B0076 05, B0076 06, B0076 0C | B0076 04, B0076 05, B0076 06 | -- | B0076 08
Center Rear Seat Belt Sensor Signal | B0077 02, B0077 06, B0077 0B | B0077 04, B0077 05, B0077 06, B0077 0C | B0077 04, B0077 05, B0077 06 | B0077 01, B0077 05 | B0077 08
Center Rear Seat Belt Sensor Low Reference | -- | B0077 04, B0077 05, B0077 06, B0077 0C | B0077 04, B0077 05, B0077 06 | -- | B0077 08
1. Indicator will remain ON with seat belt buckled. 2. Indicator will illuminate only for the bulb test.

### Circuit/System Description

The passenger seat belt switches are 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 SDM sends the status of the driver seat belt via serial data to the instrument panel cluster. After receiving the message, the instrument panel cluster controls the illumination of the passenger seat belt indicator and the display of the driver information center message.

### Reference Information

#### Schematic Reference

• | Seat Belt Schematics

• | SIR Schematics

#### Connector End View Reference

Component Connector End Views

#### 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, with a scan tool perform the IPC Display Test and verify the seat belt indicator is illuminated for 5 seconds.

⇒ | If the indicator does not illuminate, replace the P16 instrument panel cluster.

2. Monitor the scan tool Passenger Seat Belt Status parameter or the 2nd Row Seat Belt Switch parameters while connecting and disconnecting the seat belt. The parameter should display Buckled and Unbuckled when changing seat belt states.

### Circuit/System Testing

Note: When removing connectors inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector.

• | Seat belt switch

• | Seat belt switch harness connector

• | SDM

• | SDM harness connector

1. Ignition OFF, disconnect the harness connector at the appropriate passenger seat belt switch.
2. Ignition OFF, test for less than 1 Ω between the low reference circuit terminal 2 and ground.

⇒ | If greater than the specified range, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K36 SDM.

3. Ignition ON, verify the scan tool Passenger Seat Belt Switch parameter or the 2nd Row Seat Belt Switch parameter displays Buckled.

⇒ | If not the specified value, test the signal circuit for a short to ground. If the circuit tests normal replace the K36 SDM.

4. Install a 3A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool Passenger Seat Belt Switch parameter or the 2nd Row Seat Belt Switch parameter displays Unbuckled.

⇒ | If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K36 SDM.

5. If all circuits test normal, test or replace the appropriate seat belt switch.

### Component Testing

1. Ignition OFF, disconnect the harness connector at the appropriate passenger seat belt switch.
2. With the seat belt buckled, test for infinite resistance between the signal circuit terminal 1 and the low reference terminal 2.

⇒ | If less than the specified value, replace the appropriate passenger seat belt switch.

3. With the seat belt unbuckled, test for less than 1 Ω between the signal circuit terminal 1 and the low reference terminal 2.

⇒ | If greater than the specified range, replace the appropriate passenger seat belt switch.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Driver or Passenger Seat Belt Buckle Replacement

• | Control Module References for SDM and instrument panel cluster replacement, setup, and programming