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 00: Passenger Presence System Malfunction
DTC B0081 3A: Passenger Presence System Incorrect Component Installed
DTC B0081 71: Passenger Presence System Invalid Serial Data Received

### Circuit/System Description

When the ignition is turned ON, the passenger presence system and the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. When the SDM has completed the power-up mode, the SDM will establish communication with the passenger presence system. The SDM will also request the instrument panel cluster to illuminate both of the PASSENGER AIR BAG ON/OFF indicators for 5 seconds. If the SDM detects that the passenger presence system has set a current DTC, the SDM will then disable the instrument panel (I/P) module deployment loop, set DTC B0081, and illuminate the AIR BAG indicator.

### Conditions for Running the DTC

Ignition voltage is between 9-16 V.

### Conditions for Setting the DTC

Any of the following conditions must exist for 5 seconds:

#### B0081 00

The SDM has received a fault present message from the passenger presence system.

#### B0081 3A

The SDM has received a message from the passenger presence system indicating a vehicle and passenger presence system mismatch.

#### B0081 71

The SDM has received invalid or no serial data from the passenger presence system.

### Action Taken When the DTC Sets

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

• | The I/P module deployment loop will be disabled.

### 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

If either the SDM or passenger presence system were replaced, verify that the correct part numbers were used for the vehicle application.

### 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

• | Testing for Intermittent Conditions and Poor Connections

• | Connector Repairs

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

Note: A DTC B0081 set in history may not clear until the passenger presence system module enters the sleep mode. When removing connectors inspect for damage, corrosion or poor connection. Damage or corrosion in the following requires repair or replacement of the affected component/connector.

• | Passenger presence system module

• | SDM module

• | Passenger presence system module harness connector

• | SDM wiring harness connector

1. Ignition ON, retrieve DTCs from the K85 passenger presence system.
2. Verify that DTC B0081 00 is not set as current.

⇒ | If DTC B0081 00 is current, replace the K85 passenger presence system.

3. Verify that DTC B0081 3A is not set as current.

⇒ | If DTC B0081 3A is current, replace the K85 passenger presence system with the correct part number.

4. Verify DTC B1000, B1001, or U0170 is not set as current.

⇒ | If DTC B1000, B1001, or U0170 is current, refer to Diagnostic Trouble Code (DTC) List - Vehicle.

5. Verify DTC B0081 71 is not set.

⇒ | If DTC B0081 71 is set, clear the SDM DTCs. No other repairs are necessary.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | SIR/SRS Wiring Repairs

• | Control Module References for passenger presence system and SDM replacement, setup, and programming