B0100

DTC B0100

CIRCUIT DESCRIPTION
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).

DTC DESCRIPTOR
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

CONDITIONS FOR RUNNING THE DTC
Ignition 1 voltage is within the normal operating voltage range.

CONDITIONS FOR SETTING THE DTC
- 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.

ACTION TAKEN WHEN THE DTC SETS
The SDM commands the AIR BAG indicator ON via class 2 serial data.

CONDITIONS FOR CLEARING THE DTC
- 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.

DIAGNOSTIC AIDS
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 Diagnostic Aids for Circuit Testing and Wiring Repair Procedures. Component Tests and General Diagnostics

TEST DESCRIPTION

Step 1 - Step 10:

Step 11 - Step 13:

The numbers below refer to the step numbers on the diagnostic table:
2. Tests the communication status of both front end sensors.
6. Tests for a short to ground, a high resistance, or an open in the front end sensor signal circuit.
7. Tests for a short to ground, a high resistance, or an open in the front end sensor low reference circuit.
8. Tests for a short to voltage in the front end sensor signal and low reference circuits.