Airbag light is on, code B0100

Good morning.

This is a code for the sensor but diagnostics need to be done to verify. From the description, it could be a wiring issue.

There is only one sensor in the front. Sensor two is the side impact sensor.

Roy

B0100
Descriptor
Sir
Probable Causes
Connector Damaged or Corroded
Connector Harness Side
Front End Sensor
Front End Sensor Signal and Voltage Circuits Between Sensing and Diagnostic Module (SDM) Connector and Sensor Connector Open or High Resistance
Front End Sensor Signal and Voltage Circuits Short to Voltage
Sensing and Diagnostic Module (SDM)

DTC B0100

CIRCUIT DESCRIPTION
The inflatable restraint Front End Sensor also known as the electronic frontal sensor (EFS) 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 may reset the front end sensor up to 2 times by removing and reapplying power to it. If the fault is still present, the SDM will set a diagnostic trouble code (DTC).

DTC DESCRIPTORS
This diagnostic procedure supports the following DTCs:
- DTC B0100 Front End Sensor Performance
- DTC B0101 Discard Front End Sensor
- DTC B0102 Incorrect Front End Sensor Installed

CONDITIONS FOR RUNNING THE DTC
Ignition 1 voltage is within the normal operating voltage range of 9-16 volts.

CONDITIONS FOR SETTING THE DTC
- DTC B0100 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.
- A status message is not received.
- The SDM has reset the front end sensor twice without detecting a valid ID message.
- DTC B0101 will set when the SDM has received a NOK message from the front end sensor.
- DTC B0102 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.
- The SDM has reset the front end sensor twice without detecting the correct ID message.

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

CONDITIONS FOR CLEARING THE DTC
- The DTC will clear when the condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.
- 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 circuit
- High or low resistance in the front end sensor circuit
- Improper front end sensor 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 in Diagnostic Aids.

The sensor is in the front under the top of the radiator support.

It is a simple replacement.

Roy

Caution: Do not strike or jolt the inflatable restraint front end sensor. Before applying power to the front end sensor make sure that it is securely fastened. Failure to observe the correct installation procedure could cause SIR deployment, personal injury, or unnecessary SIR system repairs.

Preliminary Procedure:
Disable the supplemental inflatable restraint (SIR) system.

1. Supplemental Inflatable Restraint Front End Discriminating Sensor Bolt.

Notice: Refer to Fastener Notice in Cautions and Notices.

Tip: Loosen the TORX head bolt in order to remove sensor. The
bolt has left hand threads.

Tighten 8 N.M (71 lb in)

2. Supplemental Inflatable Restraint Front End Discriminating Sensor Assembly.

Procedure:

1. Slide the sensor towards the front of vehicle to guide the sensor bolt out of release slot.

2. Disconnect the electrical connector.

Let me know if you have any other questions.

Roy