The inflatable restraint front end sensor utilizes a unidirectional 2-wire circuit. The front end 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 front end sensor. When the ignition is turned ON and input power from the SDM is first detected, the front end 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 front end sensor continually communicates status messages to the SDM, which determines if a fault is present in the front end sensor circuit. When a fault is detected, the SDM resets the front end sensor twice by removing and reapplying power. If the fault is still present, the SDM will set a diagnostic trouble code (DTC).
This diagnostic procedure supports the following DTCs:
• | DTC B0100 Front End Sensor 1 Performance |
• | DTC B0101 Discard Front End Sensor 1 |
• | DTC B0102 Incorrect Front End Sensor 1 Installed |
• | DTC B0103 Front End Sensor 2 Performance |
• | DTC B0104 Discard Front End Sensor 2 |
• | DTC B0105 Incorrect Front End Sensor 2 Installed |
Ignition 1 voltage is within the normal operating voltage range.
• | DTC B0100 or B0103 will set when one of the following conditions occur: |
- | A valid ID message is not received within 5 seconds of the front end sensor being powered up. |
- | Status message is not received. |
- | The SDM has failed twice to reset the front end sensor. |
• | DTC B0101 or B0104 will set when the SDM has received 4 consecutive NOK (Not OK) messages from the front end sensor. |
• | DTC B0102 or B0105 will set when one of the following conditions occur: |
- | The SDM has received an ID message from the front end sensor which does not match the ID stored in the SDM memory. |
- | When 2 front end sensor resets are attempted without the correct identification being detected by the SDM. |
The SDM commands the AIR BAG indicator ON via class 2 serial data.
• | The condition responsible for setting the DTC no longer exists. |
• | You issue a scan tool CLEAR DTCs command. |
• | A history DTC will clear once 255 malfunction-free ignition cycles have occurred. |
The following are conditions that may cause the malfunction:
• | A short to ground or voltage in the front end sensor circuits |
• | High or low resistance in the front end sensor circuits |
• | Improper front end sensors installed on vehicle |
Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and connectors may result in misdiagnosis, causing a part replacement with the reappearance of the malfunction. If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections .
The numbers below refer to the step numbers on the diagnostic table:
This step tests the communication status of both front end sensors.
This step tests for a short to ground, a high resistance, or an open in the front end sensor signal circuit.
This step tests for a short to ground, a high resistance, or an open in the front end sensor low reference circuit.
This step tests for a short to voltage in the front end sensor signal and low reference circuits.
Step | Action | Yes | No |
---|---|---|---|
Schematic Reference: SIR Schematics Connector End View Reference: SIR Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
Does the scan tool indicate that either DTC B0101, B0102, B0104, or B0105 is current? | Go to Step 12 | Go to Step 3 | |
3 |
Do the front end sensor terminals or harness connector exhibit any signs of damage or corrosion? | Go to Step 4 | Go to Step 5 |
4 |
Did you complete the replacement? | Go to Step 13 | -- |
5 |
Did you find and correct the condition? | Go to Step 13 | Go to Step 6 |
Did you find and correct the condition? | Go to Step 13 | Go to Step 7 | |
Did you find and correct the condition? | Go to Step 13 | Go to Step 8 | |
Did you find and correct the condition? | Go to Step 13 | Go to Step 9 | |
9 | For DTC B0100 replace the left front end sensor. For DTC B0103 replace the right front end sensor. Refer to Inflatable Restraint Front End Sensor Replacement . Did you complete the replacement? | Go to Step 10 | -- |
10 |
Does the DTC reset? | Go to Step 11 | System OK |
11 |
Did you complete the replacement? | Go to Step 13 | -- |
12 | For DTC B0101 and B0102 replace the left front end sensor. For DTC B0104 and B0105 replace the right front end sensor. Refer to Inflatable Restraint Front End Sensor Replacement . Did you complete the replacement? | Go to Step 13 | -- |
13 |
Does the DTC reset? | Go to Step 2 | System OK |