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 Descriptors

DTC B0074 00: Passenger Occupant Classification Sensor
DTC B0074 0D: Passenger Occupant Classification Sensor Circuit Resistance Above Threshold
DTC B0074 0E: Passenger Occupant Classification Sensor Circuit Resistance Below Threshold
DTC B0074 0F: Passenger Occupant Classification Sensor Circuit Erratic (Wet Seat)

### Diagnostic Fault Information

Circuit | Short to Ground | Low Resistance | High Resistance | Open | Short to Voltage | Performance
--- | --- | --- | --- | --- | --- | ---
Pressure Sensor Signal | -- | B0074 0E | B0074 0D | B0074 0D | -- | B0074 0F
Pressure Sensor Voltage Reference | -- | B0074 0E | B0074 0D | B0074 0D | -- | --
Pressure Sensor Low Reference | -- | B0074 0E | B0074 0D | B0074 0D | -- | --

### Circuit/System Description

The passenger presence system (PPS) sensor continually monitors itself and if a fault in this circuit occurs, a DTC will set. When the sensing and diagnostic module (SDM) detects this DTC within the PPS, it will notify the customer of the enable/disable status by illuminating the OFF indicator on the PASSENGER AIR BAG ON/OFF indicators. Then the PPS will communicate to the SDM through serial data communications that a PPS fault is present. The SDM will then disable the deployment of the instrument panel (I/P) module and then illuminate the AIR BAG warning indicator.

### Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

### Conditions for Setting the DTC

• | The PPS detects the voltage at the pressure sensor signal is less than 0.5 volts or greater than 4.5 volts for 500 milliseconds.

• | The PPS detects the voltage at the pressure sensor voltage reference is less than 4.5 volts or greater than 9.1 volts for 500 milliseconds.

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

### Action Taken When the DTC Sets

• | The SDM disables the I/P module deployment loop.

• | The SDM will illuminate the OFF portion of the PASSENGER AIR BAG ON/OFF indicator.

• | 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.

### 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 in the following requires repair or replacement of the affected component/connector:

• | PPS pressure sensor

• | PPS pressure sensor wiring harness connector

1. Verify that DTC B0074 0F is not set.

⇒ | If the DTC is set, verify the seat is dry. If the seat is wet, allow 24-48 hours dry time.

2. Ignition OFF, disconnect the harness connector at the PPS sensor.
3. Test for less then 10 ohms between the ground circuit terminal 4 and ground.

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

4. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 3 and ground.

⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

5. Ignition OFF, disconnect the harness connector at the inflatable restraint rollover sensor.
6. Test for infinite resistance between the signal circuit terminal 1 and ground.

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

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

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

8. Test for less than 1 ohm on the signal circuit between the PPS sensor terminal 1 and the rollover sensor terminal 3.

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

9. Reconnect all PPS components and perform the Passenger Presence System Preload Test procedure.
10. Clear DTCs, verify DTC B0074 is not set.

⇒ | If the DTC sets, replace the PPS sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | SIR/SRS Wiring Repairs

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