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: Driver Seat Belt Sensor Circuit Short to BatteryDTC B0072 02: Driver Seat Belt Sensor Circuit Short to Ground
DTC B0072 04: Driver Seat Belt Sensor Circuit Open Circuit
DTC B0072 06: Driver Seat Belt Sensor Circuit Short To Ground or Open Circuit
DTC B0072 08: Driver Seat Belt Sensor Circuit Signal Invalid
DTC B0073 01: Passenger Seat Belt Sensor Circuit Short to Battery
DTC B0073 02: Passenger Seat Belt Sensor Circuit Short to Ground
DTC B0073 04: Passenger Seat Belt Sensor Circuit Open Circuit
DTC B0073 06: Passenger Seat Belt Sensor Circuit Short To Ground or Open Circuit
DTC B0073 08: Passenger Seat Belt Sensor Circuit Signal Invalid
Circuit/System Description
The inflatable restraint seat belt switch is within the seat belt retractor 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. The SDM monitors the seat belt switch circuits, and if a fault is detected a DTC will be set.
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 or low reference circuit is shorted to voltage for 500 milliseconds.
B0072 02, B0073 02
The SDM detects the seat switch signal circuit or low reference 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 an 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. |
| • | The SDM will store a DTC. |
Conditions for Clearing the DTC
| • | The condition 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
Electrical Information Reference
Circuit/System Testing
Important: The seat belt switch is not serviced separately. The seat belt retractor with the seat belt switch must be serviced as a complete unit. When removing connectors, inspect for damage or corrosion. Damage or corrosion in
the following requires repair or replacement of the affected component/connector:
• SDM module • Seat belt switch wiring harness connector • Seat belt switch • SDM wiring harness connector
- Ignition OFF, disconnect the seat belt switch connector.
- Test for less than 1 ohm between low reference terminal A and ground.
- Ignition ON. Test for 1.0-1.6 volts between the signal circuit terminal B and ground.
- If the circuits test normal, replace the seat belt retractor.
| ⇒ | If greater than specified, test the low reference circuit for open/high resistance. If the circuit tests normal, replace the SDM. |
| ⇒ | If less that the specified range, test the signal circuit for open/high resistance or a short to ground. If the circuit tests normal, replace the SDM. |
| ⇒ | If greater that the specified range, test the signal circuit for a short to voltage. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for SDM and PPS replacement, setup, and programming |
