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 B0071 03: Passenger Seat Belt Tension Sensor Circuit Voltage Below ThresholdDTC B0071 07: Passenger Seat Belt Tension Sensor Circuit Voltage Above Threshold
Diagnostic Fault Information
Circuit | Short to Ground | High Resistance | Open | Short to Voltage |
|---|---|---|---|---|
Belt Tension Sensor Voltage Reference | B0071 03 | B0071 03 | B0071 03 | -- |
Belt Tension Sensor Low Reference | -- | B0071 07 | B0071 07 | -- |
Belt Tension Sensor Signal | B0071 03 | B0071 03, 07 | B0071 03, 07 | B0071 07 |
Circuit/System Description
The inflatable restraint seat belt tension sensor is a 3-wire potentiometer mounted on the buckle side of the passenger 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 belt tension sensor signal circuit and if a fault is detected, DTC will be set. When the PPS detects this DTC it will send out a serial data message and the SDM will notify the customer of the enable/disable status by turning on the OFF indicator on the PASSENGER AIR BAG ON/OFF indicators. The SDM will then suppress the deployment of the instrument panel (I/P) module and turn the AIR BAG indicator on.
Conditions for Running the DTC
Ignition voltage is between 9-16 volts.
Conditions for Setting the DTC
| • | The PPS detects the voltage at the belt tension sensor signal circuit is less than 0.05 volt or greater than 4.5 volts for 500 milliseconds. |
| • | The PPS detects the voltage at the belt tension sensor voltage reference circuit is less than 4.5 volts or greater than 9.1 volts for 500 milliseconds. |
| • | The PPS detects the amperage at the belt tension sensor low reference circuit is 25 MA or greater for 500 milliseconds. |
Action Taken When the DTC Sets
| • | The PPS will set a DTC, and then communicate with the SDM via serial data communications. |
| • | The SDM disables the I/P module deployment loop. |
| • | The PPS will turn ON the passenger air bag status OFF indicator. |
| • | The SDM commands the AIR BAG indicator ON via GMLAN serial data. |
Conditions for Clearing the DTC
| • | The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used. |
| • | A history DTC will clear once 255 malfunction-free ignition cycles have occurred. |
Diagnostic Aids
Inspect the passenger seat belt tension sensor signal, voltage reference, and low reference circuits carefully for cutting and/or chafing.
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
Circuit/System Testing
Important: The seat belt tension sensor is not serviced separately. The seat belt buckle replacement with the seat belt tension sensor must be serviced as a complete unit.
- Ignition OFF, disconnect the seat belt tension sensor connector and inspect the component and harness sides for damage or corrosion.
- Ignition ON, test for 4.5-5.5 volts between the voltage reference circuit terminal A and ground.
- Ignition OFF, remove the AIR BAG BATT Fuse in the underhood fuse block. Test for less than 2.0 ohm of resistance between low reference terminal B and ground.
- Ignition OFF, disconnect the PPS module connector.
- Test the belt tension sensor signal circuit for a short to ground, open/high resistance, or short to voltage. No short to ground, open/high resistance, or short to voltage should exist.
- If all circuits test normal, replace the passenger seat belt buckle which includes the seat belt tension sensor.
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 tension sensor • The PPS module • The seat belt tension sensor wiring harness connector • The PPS module wiring harness connector
| ⇒ | If damage or corrosion is found, repair or replace as necessary. |
| ⇒ | If less that the specified range, test the voltage reference circuit for open/high resistance or a short to ground. If the circuit tests normal, replace the PPS. |
| ⇒ | If greater that the specified range, test the voltage reference circuit for a short to voltage. If the circuit tests normal, replace the PPS. |
Important: The AIR BAG BATT Fuse must be removed to ensure the PPS module is inactive. An active PPS module may cause inaccurate resistance readings.
| ⇒ | If greater than specified, test the low reference circuit for open/high resistance. If the circuit tests normal, replace the PPS. |
| ⇒ | If any of the above conditions exist, make the appropriate repair. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for PPS replacement, setup, and programming |
