For 1990-2009 cars

### Circuit Description

SIR front end sensor, also called electrical frontal collision sensor, adopts one way 2-line circuit. The front end sensor modulates the interface current, sends the ID number, operation status and deployment command to the SIR SDM. The SDM provides the front end sensor with power and ground. With ignition ON, the front end sensor detects the power provided by the SDM for the first time, it will conduct internal diagnosis and send ID to the SDM as response. If the responsive time is less than 5 seconds, the SDM will take it as valid number. The front end sensor sends the status messages continuously to the SDM, which in turn determines if the front end sensor circuit is in trouble or not. When fault is detected, the SDM will reset the front end sensor power through disconnecting and reconnecting. If the fault still exists, the SDM will set a DTC.

### DTC Descriptors

The diagnostic procedure supports the following DTCs:

• | DTC B0083: Front End Sensor 1 (Left)

• | DTC B0084: Front End Sensor 2 (Right)

The vehicle has DTCs including the DTC symptoms. Refer to DTC Symptom Description for DTC information.

DTC Symptom | DTC Symptom Descriptor
--- | ---
01 | Short to battery
02 | Short to ground
04 | Open circuit
39 | Internal electronic fault
71 | Invalid serial data received
0F | Front end sensor fault
3A | Component installed incorrectly

### Conditions for Running the DTC

Ignition 1 voltage is within normal operating range.

### Conditions for Setting the DTC

#### B0083 01 or B0084 01

• | If one or two front end sensor is short circuit to voltage.

• | The SDM fails to receive message from one or two front end sensor for more than 375 milliseconds.

#### B0083 02 or B0084 02

• | If one or two front end sensor is short circuit to ground.

• | If the current of one or two front end sensor is more than 23 mA for more than 5 milliseconds.

#### B0083 04 or B0084 04

If one or two front end sensor circuit is open.

• | B0083 39 or B0084 39

• | The SDM receives NOK message from one or two front end sensor.

• | The SDM fails to receive message from one or two front end sensor.

#### B0083 71 or B0084 71

The SDM receives invalid serial data from one or two front end sensor.

#### B0083 0F or B0084 0F

The SDM receives unsteady message from one or two front end sensor.

#### B0083 3A or B0084 3A

• | The SDM receives ID message from one or two front end sensors, however, the ID does not match the ID information in the SDM memory.

• | The SDM resets the one or two front end sensor twice and still fails to detect the correct ID information.

### Actions Taken When the DTC Sets

The SDM commands the AIR BAG indicator ON via GMLAN serial data.

### Conditions for Clearing the MIL/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

The following conditions may cause the fault:

• | One or two front end sensor circuit is open

• | One or two front end sensor circuit is short to ground or voltage

• | One or two front end sensor circuit resistance is high or low

• | The front end sensor installed in the vehicle is not correct

• | One or two front end sensor internal failure

Thoroughly inspect the wiring and connectors. Failure to do so may result in error of diagnosis and the trouble may occur again even when you replace the parts. If there is intermittent conditions, refer to Testing for Intermittent Conditions and Poor Connections .

### Test Description

The following numbers are corresponding to the steps in the diagnostic table.

1. Test if the front end sensor and front end sensor voltage circuit has high or low resistance or is open.

2. Test the continuity of the front end sensor and front end sensor voltage circuit.

3. Test if the front end sensor and front end sensor voltage circuit is short to voltage or to ground.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: SIR Schematics Connector End View Reference: SIR Connector End Views
1 | Have you conducted Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 | Important: J-45289 CANdi Module must be used together with the scan tool.

1. Install the scan tool in order to display the SIR DTCs.
2. Engine off, ignition on.

Does the scan tool indicate DTC B0083 or B0084 as current trouble code?

Go to Step 3

Go to Step 13

3 |

1. Turn the ignition switch to OFF position.
2. If DTC B0083 is set as the current DTC, disconnect the left front end sensor connector. If DTC B0084 is set as the current DTC, disconnect the right front end sensor connector. Refer to Inflatable Restraint Front End Sensor Replacement .
3. Check if the component or harness of the connector is damaged or corrosive. Refer to Testing for Intermittent Conditions and Poor Connections .

Is there damage or corrosion in the connectors?

Go to Step 4

Go to Step 5

4 |

1. Replace the front end sensor if the component of the front end sensor connector is damaged. Refer to Inflatable Restraint Front End Sensor Replacement .
2. If the front end sensor connector harness is damaged, replace the harness. Refer to Connector Repairs .

Is the trouble corrected?

Go to Step 11

--

5 |

1. Turn the ignition switch to OFF position.
2. Disconnect the SIR system sensing and diagnostic module (SDM) connector. Refer to Control Module References for replacement, set up, and programming.
3. Check if the component or harness of the SDM connector is damaged or corrosive. Refer to Testing for Intermittent Conditions and Poor Connections

Is there damage or corrosion in the connectors?

Go to Step 6

Go to Step 7

6 |

1. Replace the SDM if the component of the SDM connector is damaged. Refer to Control Module References for replacement, set up, and programming.
2. If the SDM connector harness is damaged, replace the harness. Refer to Connector Repairs .

Is the trouble corrected?

Go to Step 11

--

7 |

1. If DTC B0083 is set as the current DTC, disconnect the left front end sensor connector. If DTC B0084 is set as the current DTC, disconnect the right front end sensor connector.
2. Test if the front end sensor signal and front end sensor voltage circuit voltage is high or low, or if the SDM connector and front end sensor connector circuit is open. Refer to Circuit Testing .

Do you find and correct the condition?

Go to Step 11

Go to Step 8

8 | Test the continuity of the front end sensor and front end sensor voltage circuit. Refer to Circuit Testing . Do you find and correct the condition? | Go to Step 11 | Go to Step 9
9 |

1. Engine off, ignition on.
2. Test if the front end sensor and front end sensor voltage circuit is short to voltage or to ground. Refer to Circuit Testing and Wiring Repairs .

Do you find and correct the condition?

Go to Step 11

Go to Step 10

10 |

1. Turn the ignition switch to OFF position.
2. If DTC B0083 is set as the current DTC, replace the left front end sensor connector. If DTC B0084 is set as the current DTC, replace the right front end sensor connector. Refer to Inflatable Restraint Front End Sensor Replacement .

Did you complete the replacement?

Go to Step 11

--

11 |

1. Reconnect all SIR components.
2. Clear away all DTCs with scan tool.
3. Operate the vehicle under conditions when DTC runs as specified in supporting documents.

Does the DTC set again?

Go to Step 12

System OK

12 |

1. Turn the ignition switch to OFF position.
2. Replace the SDM module. Refer to Control Module References for replacement, set up, and programming.

Have you finished the replacement?

Go to Step 13

--

13 |

1. Engine off, ignition on.
2. Clear away all DTCs with scan tool.
3. Operate the vehicle under conditions when DTC runs as specified in supporting documents.

Does the DTC set again?

Go to Step 2

System OK