Diagnostic Instructions

DTC Descriptors

DTC B0074 03: Passenger Occupant Classification Sensor Circuit Voltage Below Threshold

DTC B0074 07: Passenger Occupant Classification Circuit Voltage Above Threshold

DTC B0074 08: Passenger Occupant Classification Circuit Signal Invalid

Diagnostic Fault Information

Circuit	Short to Ground	High Resistance	Open	Short to Voltage
Pressure Sensor Voltage Reference	B0074 07	B0074 07	B0074 07	B0074 03
Pressure Sensor Low Reference	--	B0074 03	B0074 03	B0074 07
Pressure Sensor Signal	B0071 07, 08	B0071 03, 07	B0071 03, 07	B0074 03

Circuit/System Description

The passenger presence system (PPS) uses a silicone filled sensor pad located underneath the passenger seat foam cushion and is connected by a hose clamp to a pressure sensor. The weight of the occupant sitting in the front passenger seat is measured as a pressure change within the bladder by the pressure sensor. The pressure sensor is a 3-wire sensor consisting of a high and low reference, and signal circuit. The PPS monitors the pressure 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 requesting the instrument panel cluster to turn 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

Action Taken When the DTC Sets

Conditions for Clearing the DTC

Reference Information

Schematic Reference

SIR Schematics

Connector End View Reference

SIR Connector End Views

SIR System Description and Operation

SIR System Description and Operation

Electrical Information Reference

Circuit/System Testing

Important: The PPS pressure sensor is not serviced separately. The PPS replacement with the PPS pressure sensor must be serviced as a complete unit.

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 PPS pressure sensor

•	The PPS module

•	The PPS pressure sensor wiring harness connector

•	The PPS module wiring harness connector

1. Ignition OFF, disconnect the PPS pressure sensor connector and inspect the component and harness sides for damage or corrosion.

⇒	If damage or corrosion is found, repair or replace as necessary.

2. Ignition ON, test for 4.5-5.5 volts between the voltage reference circuit terminal A and ground.

⇒	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 AIRBAG Fuse that supplies B+ 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 2.0 ohms of resistance between low reference terminal C and ground.

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

4. Ignition OFF, disconnect the PPS module connector.
5. Test the pressure 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 any of the above conditions exist, make the appropriate repair.

6. If all circuits test normal, replace the PPS which includes the pressure sensor, module and seat foam.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.