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. |
DTC Descriptors
DTC B0072 01: Left Front Seat Belt Sensor Circuit Short to BatteryDTC B0072 02: Left Front Seat Belt Sensor Circuit Short to Ground
DTC B0072 04: Left Front Seat Belt Sensor Circuit Open Circuit
DTC B0072 06: Left Front Seat Belt Sensor Circuit Short To Ground or Open Circuit
DTC B0072 08: Left Front Seat Belt Sensor Circuit Signal Invalid
DTC B0073 01: Right Front Seat Belt Sensor Circuit Short to Battery
DTC B0073 02: Right Front Seat Belt Sensor Circuit Short to Ground
DTC B0073 04: Right Front Seat Belt Sensor Circuit Open Circuit
DTC B0073 06: Right Front Seat Belt Sensor Circuit Short To Ground or Open Circuit
DTC B0073 08: Right Front Seat Belt Sensor Circuit Signal Invalid
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Driver Seat Belt Switch Signal | B0072 02, B0072 06 | B0072 04, B0072 06 | B0072 01 | B0072 08 |
Passenger Seat Belt Switch Signal | B0073 02, B0073 06 | B0073 04, B0073 06 | B0073 01 | B0073 08 |
Low Reference | -- | B0072 04, B0073 04 | -- | -- |
Circuit/System Description
The seat belt buckle switch is located within the seat belt buckle assembly and provides an input to the inflatable restraint sensing and diagnostic module (SDM). The SDM supplies a low reference circuit and a seat belt switch signal circuit to determine a buckled or unbuckled condition.
Conditions for Running the DTC
Ignition voltage is between 9-16 volts.
Conditions for Setting the DTC
B0072 01, B0073 01
The SDM detects the seat switch signal circuit is shorted to voltage for 500 milliseconds.
B0072 02, B0073 02
The SDM detects the seat switch signal circuit is shorted to ground for 500 milliseconds.
B0072 04, B0073 04
The SDM detects the seat switch signal circuit or low reference circuit is open for 500 milliseconds.
B0072 06, B0073 06
The SDM detects the seat switch signal circuit or low reference circuit is shorted to ground or is open for 500 milliseconds.
B0072 08, B0073 08
The SDM detects an invalid signal in the seat switch signal circuit.
Action Taken When the DTC Sets
The SDM requests the instrument panel cluster (IPC) to illuminate the AIR BAG indicator.
Conditions for Clearing the DTC
| • | The conditions for setting the DTC no longer exists. |
| • | A history DTC will clear once 100 malfunction-free ignition cycles have occurred. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
SIR System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, observe the appropriate scan tool Seat Belt Switch parameter while buckling and unbuckling the seat belt. The parameter should change between Buckled and Unbuckled.
Circuit/System Testing
Important: When removing connectors, inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the appropriate component/connector:
• The SDM • The SDM wiring harness connector • The seat belt buckle • The seat belt buckle wiring harness connector
- Ignition OFF, disconnect the harness connector of the appropriate seat belt switch.
- Ignition OFF, test for less than 10 ohms between the low reference circuit terminal B and ground.
- Ignition ON, verify the appropriate scan tool Seat Belt Switch parameter is Unbuckled.
- Install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the appropriate scan tool Seat Belt Switch parameter is Buckled.
- If all circuits test normal, test or replace the seat belt buckle assembly.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the SDM. |
| ⇒ | If not the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the SDM. |
| ⇒ | 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 SDM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for SDM replacement, setup, and programming |
