For 1990-2009 cars

### Circuit Description

The inflatable restraint front end discriminating sensor is a crash sensing device used in the detection of a frontal collision. The front end discriminating sensor is used by the inflatable restraint sensing and diagnostic module (SDM) to help determine whether or not certain frontal crashes are severe enough to warrant deployment of the frontal air bags. The SDM applies voltage to the discriminating sensor - reference circuit and monitors the voltage at the discriminating sensor - signal circuit in order to verify proper circuit integrity. If the SDM detects a malfunction within the discriminating sensor circuit, a DTC will be set.

### Conditions for Running the DTC

Ignition 1 Voltage is within the normal operating voltage range.

### Conditions for Setting the DTC

The SDM detects a malfunction in the inflatable restraint front end discriminating sensor - right circuit.

### Action Taken When the DTC Sets

The SDM commands the AIR BAG indicator ON.

### Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

### Diagnostic Aids

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.

The following are possible causes of the malfunction:

• | An open or high resistance in the front end discriminating sensor - right circuits

• | A short to ground or voltage in the front end discriminating sensor - right circuits

• | An internal front end discriminating sensor - right malfunction

• | An internal SDM malfunction

If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. Tests the front end discriminating sensor for the proper resistance value.

2. Tests for an open, short to ground, or short to voltage in the front end discriminating sensor - right circuits.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: SIR Schematics
1 | Did you perform A Diagnostic System Check - SIR? | -- | Go to Step 2 | Go to Diagnostic System Check - SIR
2 |

1. Turn OFF the ignition.
2. Disconnect the front end discriminating sensor - right connector.
3. Inspect both the component and harness sides of the connector for the following conditions:

• | Corrosion

• | Damaged terminals

• | Poor contact/terminal tension

Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 8

Go to Step 3

3 | Measure the resistance between the front end discriminating sensor - right terminals. Refer to Circuit Testing in Wiring Systems. Does the resistance measure within the specified range? | 754 - 886 ohms | Go to Step 4 | Go to Step 6
4 |

1. Disconnect the SDM connector.
2. Inspect the SDM connector for the following conditions:

• | Corrosion

• | Damaged terminals

• | Poor contact/terminal tension

Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 8

Go to Step 5

5 | Test the front end discriminating sensor - right - signal and the front end discriminating sensor - right - reference circuits for the following conditions:

• | An open or high resistance

• | A short to ground

• | A short to voltage

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 8

Go to Step 7

6 | Replace the Inflatable Restraint Front End Discriminating Sensor - Right. Refer to Inflatable Restraint Front End Discriminating Sensor Replacement - Right Side . Did you complete the replacement? | -- | Go to Step 8 | --
7 | Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Did you complete the replacement? | -- | Go to Step 8 | --
8 |

1. Reconnect all SIR components.
2. Verify that all components, connectors and CPAs are properly mounted.
3. Use the scan tool in order to Clear the DTCs.
4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK