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

### Diagnostic Fault Information

Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance
--- | --- | --- | --- | --- | ---
Front End Sensor 1 High Signal | B0083 02 | B0083 04 | B0083 04 | B0083 01 | B0083 3A
Front End Sensor 1 Low Reference | B0083 02 | B0083 04 | B0083 04 | B0083 01 | B0083 3A
Front End Sensor 2 High Signal | B0084 02 | B0084 04 | B0084 04 | B0084 01 | B0084 3A
Front End Sensor 2 Low Reference | B0084 02 | B0084 04 | B0084 04 | B0084 01 | B0084 3A
Left Front Side Impact Sensor High Signal | B0085 02 | B0085 04 | B0085 04 | B0085 01 | B0085 3A
Left Front Side Impact Low Reference | B0085 02 | B0085 04 | B0085 04 | B0085 01 | B0085 3A
Right Front Side Impact Sensor High Signal | B0086 02 | B0086 04 | B0086 04 | B0086 01 | B0086 3A
Right Front Side Impact Low Reference | B0086 02 | B0086 04 | B0086 04 | B0086 01 | B0086 3A

### Circuit/System Description

The inflatable restraint side impact sensor utilizes a unidirectional 2-wire circuit. The side impact sensor modulates current on the interface to send ID, state of health, and deployment commands to the inflatable restraint sensing and diagnostic module (SDM). The SDM serves as a power source and a ground for the side impact sensor. When the ignition is turned ON and input power from the SDM is first detected, the side impact sensor responds by performing internal diagnostics and sending an ID to the SDM. The SDM considers the ID to be valid if the response time is less than 5 seconds. The side impact sensor continually communicates status messages to the SDM, which determines if a fault is present in the side impact sensor circuit. When a fault is detected, the SDM may reset the side impact sensor up to 2 times by removing and reapplying power to it. If the fault is still present, the SDM will set a DTC.

### Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

### Conditions for Setting the DTC

All of the following conditions exist for 2.5 seconds:

#### B0085 01 or B0086 01

• | The side impact sensor (SIS) has been shorted to voltage.

• | The SDM has not received a message from the SIS for more than 2.5 milliseconds

#### B0085 02 or B0086 02

• | The side impact sensor has been shorted to ground.

• | The side impact sensor current has been above 23 mA for longer than 5 milliseconds.

#### B0085 04 or B0086 04

The SIS circuit is open

#### B0085 39 or B0086 39

• | The SDM has received a NOK message from the side impact sensor.

• | The SDM has not received a message.

#### B0085 71 or B0086 71

The SDM has received invalid serial data from the side impact sensor.

#### B0085 3A or B0086 3A

• | The SDM has received an ID message from the side impact sensor, which does not match the ID stored in the SDM memory.

• | The SDM has reset the side impact sensor twice without detecting the correct ID message.

### Action Taken When the DTC Sets

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

• | The SIR System is disabled and no deployments are allowed.

### 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

#### 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: Refer to SIR Service Precautions.

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

• | Side Impact sensor

• | SDM module

• | Side Impact sensor wiring harness connector

• | SDM wiring harness connector

1. Ignition OFF, disconnect the X2 harness connector at the SDM and the harness connector at the appropriate side impact sensor.
2. Ignition ON, test for less than 1 volt between the appropriate side impact sensor low reference circuit terminal 2 and ground.

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

3. Ignition ON, test for less than 1 volt between the appropriate side impact sensor signal circuit terminal 1 and ground.

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

4. Test for infinite resistance between the appropriate side impact sensor signal circuit terminal 2 and ground.

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

5. Test for less than 1 ohm between the appropriate side impact sensor low reference circuit terminals listed below:

• | Left side impact sensor terminal 2 and SDM terminal 25 X2.

• | Right side impact sensor terminal 2 and SDM terminal 28 X2.

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

6. Test for less than 1 ohm between the appropriate side impact sensor signal circuit terminals listed below:

• | Left side impact sensor terminal 1 and SDM terminal 26 X2.

• | Right side impact sensor terminal 1 and SDM terminal 27 X2

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

7. If all circuits test normal, replace the appropriate side impact sensor.
8. Reconnect all SIR components. Ignition ON, verify the DTC does not set as current.

⇒ | If the DTC resets as current, replace the SDM.

### Repair Instructions

• | Inflatable Restraint Side Impact Sensor Replacement.

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