B0084

DTC B0084

CIRCUIT DESCRIPTION
The inflatable restraint Front End Sensor also known as the electronic frontal sensor (EFS) utilizes a unidirectional 2-wire circuit. The EFS 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 EFS. When the ignition is turned on and input power from the SDM is first detected, the EFS 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 EFS continually communicates status messages to the SDM, which determines if a fault is present in the EFS circuit. When a fault is detected, the SDM may reset the EFS up to two 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




- DTC B0084 Front End Sensor 2

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

CONDITIONS FOR SETTING THE DTC
All of the following conditions exist for 2.5 seconds:

B0084 01
- The EFS has been shorted to voltage.
- The SDM has not received a message from the EFS for more than 375 milliseconds.

B0084 02
- The EFS has been shorted to ground.
- The EFS current has been above 23 mA for longer than 5 milliseconds.

B0084 39
- The EFS circuit is open.
- The SDM has received a NOK message from the EFS.
- The SDM has not received a message.

B0084 71
The SDM has received invalid serial data from the EFS

B0084 0F
The SDM has received erratic messages from the EFS.

B0084 3A
- The SDM has received an ID message from the EFS which does not match the ID stored in the SDM memory.
- The SDM has reset the EFS twice without detecting the correct ID message.

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

CONDITIONS FOR CLEARING THE MIL/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:
- An open in the EFS circuit
- A short to ground or voltage in the EFS circuit
- High or low resistance in the EFS circuit
- Improper EFS installed on vehicle
- An internal failure in the EFS

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 and Poor Connections in Diagnostic aids.

TEST DESCRIPTION

Steps 1-3:

Steps 4-6:

Steps 7-11:

Steps 12-13:

The numbers below refer to the step numbers on the diagnostic table.
7. Tests the EFS signal and EFS voltage circuits for high or low resistance or open
8. Tests between the EFS signal and EFS voltage circuits for continuity
9. Tests the EFS signal and EFS voltage circuits for a short to voltage or ground.