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 B0061: Left Front/Driver Roof Rail/Head Curtain Bag Deployment Loop Resistance Low
DTC B0062: Left Front/Driver Roof Rail/Head Curtain Bag Deployment Loop Open
DTC B0068: Left Front/Driver Roof Rail/Head Curtain Bag Deployment Loop Voltage Out of Range

### Diagnostic Fault Information

Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance
--- | --- | --- | --- | --- | ---
Roof Rail Module - Left High Control | B0068 | B0068 | B0062 | B0068 | B0061
Roof Rail Module - Left Low Control | B0068 | B0068 | B0062 | B0068 | B0061

### Circuit/System Description

The driver roof rail deployment loop consists of an inflatable restraint roof rail module - left and the roof rail module high and low circuits. A shorting bar used within the roof rail module connector shorts together both the roof rail module high and low circuits when the connector is disconnected. This will help to prevent unwanted deployment of the inflator module during servicing. During a side or frontal crash of sufficient force the inflatable restraint sensing and diagnostic module (SDM) will allow current to flow through the deployment loop in order to deploy the roof rail module. The SDM performs continuous diagnostic tests on the deployment loops to check for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a diagnostic trouble code (DTC) will be stored in memory.

### Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

### Conditions for Setting the DTC

#### B0061

DTC B0061 will set when the roof rail module-left deployment loop resistance is less than 1.3 ohms for 500 milliseconds.

#### B0062

DTC B0062 will set when one of the following conditions occurs:

• | Roof rail module-left high circuit is less than 2.4 volts and the roof rail module-left deployment loop is greater than 6 ohms for 500 milliseconds.

• | Roof rail module-left deployment loop resistance is greater than 4.8 ohms for 500 milliseconds.

#### B0068

DTC B0068 will set when one of the following conditions occur:

• | Roof rail module-left high or low circuits are shorted to voltage or shorted to ground for 500 milliseconds.

• | Roof rail module-left high circuit is less than 2.4 volts and roof rail module-left deployment loop resistance is less than 6 ohms for 500 milliseconds.

### 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

#### 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

#### Special Tools

• | EL 38715-125 Load Tool Adapter

• | J 38715-A SIR Driver/Passenger Load Tool

### Circuit/System Testing

Important: Refer to SIR Service Precautions .

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

• | Inflatable restraint module

• | SDM module

• | Front end sensor wiring harness connector

• | SDM wiring harness connector

Important: The connector and connector position assurance (CPA) may seat independent of each other. Both the connector and CPA should seat with an audible and/or tactile click. The CPA isolates the shoring-bars within the connector allowing the deployment circuit to operate properly.

1. Verify that the LF inflatable restraint side impact module connector and CPA are engaged.

⇒ | If the above condition is not found, make the appropriate repair.

2. Ignition OFF, disconnect the harness connector at the left roof rail inflatable restraint module.
3. With the appropriate load tool adapter, connect J 38715-A in place of the left roof rail inflatable restraint module.
4. Ignition ON, with a scan tool, verify that the appropriate DTC is set as current.

⇒ | If the DTC is not set or is set as history, cycle the ignition OFF, disconnect the load tool and adapter, reconnect the harness connector at the left roof rail inflatable restraint module, and cycle the ignition ON. If the DTC resets after reconnecting the module, replace the left roof rail inflatable restraint module.

5. Ignition OFF, disconnect the load tool and the adapter.
6. Disconnect the harness connector at the SDM.
7. Ignition ON, test for less than 1.0 volt between the low control circuit terminal 16 and ground.

⇒ | If not within the specified range, test the control circuit for a short to voltage.

8. Ignition ON, test for less than 1.0 volt between the high control circuit terminal 17 and ground.

⇒ | If not within the specified range, test the control circuit for a short to voltage.

9. Ignition OFF, test for infinite resistance between the low control circuit terminal 16 and ground.

⇒ | If not within the specified range, test the control circuit for a short to ground.

10. Ignition OFF, test for infinite resistance between the high control circuit terminal 17 and ground.

⇒ | If not within the specified range, test the control circuit for a short to ground.

11. Test for less than 1.0 ohm between the low control circuit terminal 4 and the SDM terminal 16.

⇒ | If not within the specified range, test the control circuit for an open/high resistance.

12. Test for less than 1.0 ohm between the high control circuit terminal 3 and the SDM terminal 17.

⇒ | If not within the specified range, test the control circuit for an open/high resistance.

13. If all circuits test normal, replace the SDM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Inflatable Restraint Roof Side Rail Module Replacement - Front

• | SIR/SRS Wiring Repairs

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