B1678

SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: B1678, B1679; Lost Communication with Rear Floor Airbag Sensor LH; 2013 MY FR-S [03/2012 -]
B1678 - Lost Communication with Rear Floor Airbag Sensor LH
B1679 - Rear Floor Airbag Sensor LH Initialization Incomplete

DESCRIPTION

* The No. 2 airbag sensor assembly circuit consists of the airbag ECU assembly and No. 2 airbag sensor assembly.

* The No. 2 airbag sensor assembly detects impacts to the vehicle and sends signals to the airbag ECU assembly to determine if the airbag should be deployed.

* These DTCs are stored when a malfunction is detected in the No. 2 airbag sensor assembly circuit.





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work Service Precautions.

PROCEDURE

1. CHECK CONNECTORS

(a) Turn the ignition switch off.

(b) Disconnect the cable from the negative (-) battery terminal.

CAUTION:
Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

(c) Check that the connectors are properly connected to the airbag ECU assembly and No. 2 airbag sensor assembly.

OK:

The connectors are properly connected.

HINT
If the connectors are not connected securely, reconnect the connectors and proceed to the next inspection.

(d) Disconnect the connectors from the airbag ECU assembly and No. 2 airbag sensor assembly.

(e) Check that the terminals of connectors are not damaged.

OK:

The connectors are not deformed or damaged.

NG -- REPLACE FLOOR WIRE
OK -- Continue to next step.

2. CHECK FLOOR WIRE (OPEN)

(a) Using a service wire, connect terminals 11 (BBL2+) and 12 (BBL2-) of connector B.









NOTICE:
Do not forcibly insert the service wire into the terminals of the connector when connecting the wire.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





(c) Disconnect the service wire from connector B.

NG -- REPLACE FLOOR WIRE
OK -- Continue to next step.

3. CHECK FLOOR WIRE (SHORT)

(a) Measure the resistance according to the value(s) in the table below.









Standard Resistance:





NG -- REPLACE FLOOR WIRE
OK -- Continue to next step.

4. CHECK FLOOR WIRE (SHORT TO B+)

(a) Connect the cable to the negative (-) battery terminal.









(b) Turn the ignition switch to ON.

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





(d) Turn the ignition switch off.

(e) Disconnect the cable from the negative (-) battery terminal.

CAUTION:
Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

NG -- REPLACE FLOOR WIRE
OK -- Continue to next step.

5. CHECK FLOOR WIRE (SHORT TO GROUND)

(a) Measure the resistance according to the value(s) in the table below.









Standard Resistance:





NG -- REPLACE FLOOR WIRE
OK -- Continue to next step.

6. CHECK NO. 2 AIRBAG SENSOR ASSEMBLY

(a) Connect the connectors to the No. 2 airbag sensor assembly and airbag ECU assembly.









(b) Replace the No. 2 airbag sensor assembly with a new one.

(c) Connect the cable to the negative (-) battery terminal.

(d) Clear the DTCs stored in memory Reading and Clearing Diagnostic Trouble Codes.

(e) Turn the ignition switch off.

(f) Turn the ignition switch to ON, and wait for at least 60 seconds.

(g) Check for DTCs Reading and Clearing Diagnostic Trouble Codes.

:





HINT
Codes other than DTCs B1678 and B1679 may be output at this time, but they are not related to this check.

B -- REPLACE AIRBAG ECU ASSEMBLY Removal

A -- END (NO. 2 AIRBAG SENSOR ASSEMBLY WAS DEFECTIVE)