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 B0081 3A: PPS Components Incorrectly Installed
DTC B0081 39: PPS Internal Electronic Fault
DTC B0081 71: PPS Receives Invalid Serial Data

### Circuit/System Description

Ignition ON, SIR SDM performs self-inspection to diagnose if there is critical fault.

When the SDM fulfills power on mode, the SDM establishes communication with the PPS. The PPS commands the 2 passenger air bags enabling/disabling indicator ON for 5 seconds as the response. The SDM sends a request message to the PPS to receive its calibration ID. The PPS sends the calibration ID to the SDM, which compares the received ID with the data stored in the memory. If the data stored in the memory and the information sent by the PPS cannot match and the DTC has detected the PPS has already set a current DTC, the SDM will disable the I/P module deployment circuit, set DTC B0081 and command the air bag indicator ON.

### Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

### Conditions for Setting the DTC

All the following conditions must last for 5 seconds:

#### B0081 3A

• | The SDM receives ID message from PPS, however, the ID does not match the ID information in the SDM memory.

• | The SDM resets the PPS twice and still fails to detect the correct ID information.

#### B0081 39

• | The SDM receives the NOK message from the PPS.

• | The SDM fails to receive message.

#### B0081 71

The SDM receives an invalid serial data from the PPS.

### Actions Taken When the DTC Sets

• | The SDM commands the AIR BAG indicator ON via serial data communications.

• | I/P module deployment circuit will be disabled.

### Conditions for Clearing DTC

• | When conditions for the DTC to set no longer exist, use CLEAR DTC function of the scan tool to clear the DTC.

• | After 255 consecutive warm-up cycles without failure, the DTC will be cleared.

### Diagnostic Aids

If the SDM or PPS is replaced, check and verify the system part number used in the vehicle is correct.

### Reference Information

#### Schematic Reference

SIR Schematics

#### Connector End View Reference

SIR Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

### 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 module

• | The SDM module

• | PPS wiring harness connector

• | The SDM harness connector

1. Ignition ON, the PPS will illuminate the system ON/OFF indicator. Check and verify the PPS will illuminate the system ON/OFF indicator.

⇒ | If the passenger airbag ON/OFF status indicator is not ON, refer to Passenger Presence System Indicator Circuit Malfunction .

2. Ignition ON, use the scan tool. Go to PPS menu, then retrieve the DTCs. Refer to Diagnostic Trouble Code (DTC) List - Vehicle to verify that no PPS DTC sets.

⇒ | If the PPS stores any current or history DTC, you have to correct the PPS DTC first. Refer to the Diagnostic Trouble Code (DTC) List - Vehicle .

3. Check if the PPS is replaced. Check and verify the vehicle has installed correct PPS.

⇒ | If wrong PPS is installed, replace with a correct one.

4. Ignition OFF, disconnect the PPS module connector. Refer to Inflatable Restraint Passenger Presence System Replacement - Front for location of connector.
5. Remove the SDM connector. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement for location of connector.
6. Test if the passenger sensor serial data circuit between the PPS and SDM connectors is open or has high resistance. Check and verify no open circuit or high resistance exists.

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

7. Test the PPS ignition 1 voltage circuit for high resistance or short to ground or open circuited. Check and verify no high resistance, an open or short to voltage exist.

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

8. Replace the PPS.
9. Ignition ON, use the scan tool to clear the DTC, and then check again if DTC B0081 sets. Check and verify there is no DTC set.

⇒ | If DTC B0081 resets, replace the SDM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Refer to Control Module References for SDM replacement, setup and programming.