Diagnostic Instructions

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

DTC B0073 06: Passenger Seat Belt Sensor Circuit Short to Ground or Open Circuit

DTC B0073 08: Passenger Seat Belt Sensor Circuit Signal Invalid

Diagnostic Fault Information

Circuit	Short to Ground	High Resistance	Open	Short to Voltage	Signal Performance
Seat Belt Sensor Right Low Reference	B0073 02, 06	--	B0073 04	B0073 01	B0073 08
Seat Belt Sensor Right Signal	B0073 02, 06	--	B0073 04	B0073 01	B0073 08

Circuit/System Description

The inflatable restraint seat belt tension sensor is a 3-wire potentiometer mounted on the retractor or buckle side of the seat belt and provides an input to the passenger presence system (PPS). When an infant car seat is properly restrained on the front passenger seat, the seat belt is tightly secured through the car seat. The seat belt pulls on the tension sensor and changes the voltage signal to the PPS module. The PPS monitors the seat belt tension sensor circuit and if a fault is detected, a DTC will be set. When the PPS detects this DTC within the PPS, it will notify the customer of the enable/disable status by turning ON the OFF indicator on the PASSENGER AIR BAG ON/OFF indicators. Then the PPS will communicate to the sensing and diagnostic module (SDM) through a serial data communications circuit that a PPS fault is present. The PPS will set a DTC then communicate to the SDM to suppress the deployment of the instrument panel (I/P) module and then turn the AIR BAG indicator ON.

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

B0073 01

The SDM detects the seat belt sensor circuit is shorted to voltage for 500 milliseconds.

B0073 02

The SDM detects the seat belt sensor circuit is shorted to ground for 500 milliseconds.

B0073 04

The SDM detects the seat belt sensor circuit is open for 500 milliseconds.

B0073 06

The SDM detects the seat belt sensor circuit is shorted to ground or an open occur for 500 milliseconds.

B0073 08

The SDM detects the seat belt sensor signal circuit is invalid for 500 milliseconds.

Action Taken When the DTC Sets

Conditions for Clearing the DTC

Reference Information

Electrical Information Reference

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:

-	The seat belt retractor pretensioner - RF

-	The PPS module

-	The SDM module

-	The seat belt retractor pretensioner - RF wiring harness connector

-	The PPS wiring harness connector

-	The SDM wiring harness connector

1. Ignition OFF, disconnect the seat belt sensor. Refer to seat belt retractor - right front replacement in Repair Instructions for location of connector.
2. Disconnect the PPS module connector. Refer to PPS replacement in Repair Instructions for location of connector.
3. Test the seat belt tension retractor sensor signal circuit for a short to ground, a high resistance, or an open. Verify that a short to ground, a high resistance, or an open does not exist.

⇒	If any of the above conditions are found, make the appropriate repair.

4. Test the seat belt tension retractor sensor 5-volt reference circuit for a short to ground, a short to voltage, a high resistance, or an open. Verify that a short to ground, a short to voltage, a high resistance, or an open does not exist.

⇒	If any of the above conditions are found, make the appropriate repair.

5. Test the seat belt tension retractor sensor low reference circuit for a short to ground, a short to voltage, a high resistance, or an open. Verify that a short to ground, a short to voltage, a high resistance, or an open does not exist.

⇒	If any of the above conditions are found, make the appropriate repair

6. Ignition ON, engine OFF test the seat belt tension retractor sensor circuit with a DMM. Measure the voltage of the seat belt tension retractor sensor circuit harness side and ground. The voltage should read 0.05-4.5 volts.

⇒	If the voltage is more than 5 volts, test the seat belt tension retractor sensor circuit for a short to voltage. If the circuit tests good, replace the PPS.

7. Reconnect all PPS components. Use the scan tool to clear all PPS DTCs. Rezero the PPS. Refer to Passenger Presence System Rezeroing . Verify DTC B0073 does not exist.

⇒	If DTC B0073 reset, replace the PPS.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.