Diagnostic Instructions

DTC Descriptors

DTC B0072 01: Driver Seat Belt Sensor Circuit Short to Voltage

DTC B0072 02: Driver Seat Belt Sensor Circuit Short to Ground

DTC B0072 05: Driver Seat Belt Sensor Circuit Short to Battery or Open

DTC B0072 08: Driver Seat Belt Sensor Circuit Signal Invalid

Diagnostic Fault Information

Circuit	Short to Ground	High Resistance	Open	Short to Voltage	Signal Performance
Seat Belt Sensor Driver Low Reference	--	B0072 05, 2	B0072 05, 2	2	B0072 08
Seat Belt Sensor Driver Signal	B0072 02, 1	--	B0072 05, 2	B0072 01, 2	B0072 08
1. Indicator will remain ON with seat belt buckled 2. Indicator will illuminate only for the bulb test

Circuit/System Description

The inflatable restraint seat belt buckle switch is within the seat belt buckle 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

The SDM detects the seat belt sensor circuit is shorted to voltage for 2 seconds.

B0072 02

The SDM detects the seat belt sensor circuit is shorted to ground for 2 seconds.

B0072 05

The SDM detects the seat belt sensor circuit is open for 2 seconds.

B0072 08

The SDM detects the seat belt sensor signal circuit is invalid for 2 seconds.

Action Taken When the DTC Sets

Conditions for Clearing the DTC

Reference Information

Schematic Reference

SIR Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool Driver Seat Belt Switch parameter while buckling and unbuckling the seat belt. The reading should be Not Buckled when the seat belt is unbuckled and the seat belt switch is closed. The reading should be Buckled when the seat belt is buckled and the seat belt switch is open.

Circuit/System Testing

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

•

SDM.

•	Seat belt sensor wiring harness connector.

•	SDM wiring harness connector.

1. Ignition OFF, disconnect the harness connector of the seat belt switch.
2. Test for less than 1 ohm between low reference circuit terminal 1 and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the SDM.

3. Ignition ON, verify the scan tool Driver Seat Belt switch parameter is Buckled.

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

4. Connect a 3A fused jumper wire between the signal circuit terminal 2 and the low reference circuit terminal 1. Verify the scan tool Driver Seat Belt Switch parameter is Not Buckled.

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

5. If the circuits test normal, replace the seat belt buckle switch.

Repair Instructions

perform the Diagnostic Repair Verification after completing the diagnostic procedure.