B0073

DTC B0073

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)provides an overview of each diagnostic category.



DTC Descriptors
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 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

B0073 01

The SDM detects the seat switch signal circuit or low reference circuit is shorted to voltage for 500 milliseconds.

B0073 02

The SDM detects the seat switch signal circuit or low reference circuit is shorted to ground for 500 milliseconds.

B0073 04

The SDM detects the seat switch signal circuit or low reference circuit is open for 500 milliseconds.

B0073 06

The SDM detects the seat switch signal circuit or low reference circuit is shorted to ground or an open for 500 milliseconds.

B0073 08

The SDM detects an invalid signal in the seat switch signal circuit.


Action Taken When the DTC Sets

* The SDM commands ON the AIR BAG warning lamp via serial data communications.
* The SDM will store a DTC.



Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 100 malfunction-free ignition cycles have occurred.



Reference Information
Schematic Reference

Seat Belt Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)



Circuit/System Testing

Important:
* The seat belt buckle switch is not serviced separately. The seat belt buckle with the seat belt buckle 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:


- The SDM

- The seat belt buckle switch wiring harness connector

- The seat belt buckle switch

- The SDM wiring harness connector





1. Ignition OFF, disconnect the harness connector of the seat belt switch.
2. Test for less than 1.0 ohm of resistance between low reference terminal A and ground.

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

3. Ignition ON. Test for 1.0 - 1.6 volts between the signal circuit terminal B and ground.

• 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.

4. If the circuits test normal, replace the seat belt buckle.



Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Seat Belt Retractor Pretensioner Replacement - Front (Removal and Replacement)
* SIR/SRS Wiring Repairs (Component Tests and General Diagnostics)
* Programming and Relearning (Programming and Relearning)for SDM replacement, setup, and programming