For 1990-2009 cars

### 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 Descriptor

DTC 023: Seat Belt Tension Sensor Circuit Out of Range

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
5-Volt Reference | 023 | 023 | 023 | --
Seat Belt Tension Sensor Signal | 023 | 023 | 023 | --
Low Reference | -- | 023 | -- | --

### Circuit/System Description

The inflatable restraint seat belt tension sensor is used to enhance the passenger presence system (PPS) when an infant car seat is properly restrained on the front outboard passenger seat. The seat belt tension sensor is a 3-wire potentiometer mounted on the lower seat belt anchor and provides an input to the PPS module. When an infant car seat is properly restrained on the front passenger seat, the seat belt is tightly secured through the infant car seat. The seat belt pulls on the tension sensor and changes the voltage signal to the PPS module. The PPS module uses the voltage signal to help determine if a tightly belted infant car seat is installed. The PPS uses the inputs from the seat belt tension sensor and the PPS pressure sensor to determine if the instrument panel (I/P) module should be suppressed or enabled. The PPS monitors the seat belt tension sensor circuits and sets DTC 023 if a fault is detected.

### Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

### Conditions for Setting the DTC

• | The PPS detects the voltage at the passenger seat belt tension sensor signal is less than 0.5 volt or greater than 4.5 volts for 500 milliseconds.

• | The PPS detects the voltage at the passenger seat belt tension sensor 5-volt reference is less than 4.5 volts or greater than 9.1 volts for 500 milliseconds.

• | The PPS detects the amperage at the passenger seat belt tension sensor low reference is 25 mA or greater for 500 milliseconds.

### Action Taken When the DTC Sets

• | The SDM disables the instrument panel (I/P) module deployment loop.

• | The SDM requests the instrument panel cluster (IPC) to illuminate the AIR BAG indicator.

### 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.

### Diagnostic Aids

Inspect the passenger seat belt tension sensor signal, 5-volt reference, and low reference circuits carefully for cutting and/or chafing.

### Reference Information

#### Schematic Reference

SIR Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

SIR System Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information.

### Circuit/System Testing

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

• | Seat belt buckle - passenger

• | PPS module

• | Seat belt buckle - passenger wiring harness connector

• | PPS wiring harness connector

1. Ignition OFF, disconnect the X2 harness connector at the inflatable restraint passenger seat belt tension sensor.
2. Ignition ON, test for 4.5-5.5 volts between the voltage reference circuit terminal B X2 and ground.

⇒ | If less that the specified range, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the PPS module.

⇒ | If greater that the specified range, test the voltage reference circuit for a short to voltage. If the circuit tests normal, replace the PPS module.

Important: The AIRBAG fuse that supplies ignition voltage must be removed to ensure the PPS module is inactive. An active PPS module may cause inaccurate resistance readings.

3. Ignition OFF, remove the AIRBAG fuse. Test for less than 3 ohms between the low reference circuit terminal A X2 and ground.

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

4. Ignition OFF, disconnect the harness connector at the PPS module.
5. Test for infinite resistance between the signal circuit terminal 4 and ground.

⇒ | If less than the specified value, test the signal circuit for a short to ground.

6. Ignition ON, test for less than 1 volt between the signal circuit terminal 4 and ground.

⇒ | If greater than the specified range, test the signal circuit for a short to voltage.

7. Test for less than 1 ohm between the signal terminal 4 and circuit terminal C X2 at the sensor harness connector.

⇒ | If greater than the specified range, test the signal circuit for an open/high resistance.

8. If all circuits test normal, replace the seat belt buckle.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Front Seat Belt Buckle Replacement

• | SIR/SRS Wiring Repairs

• | Control Module References for PPS replacement, setup, and programming