Lexus IS250 · Service Manual RESTRAINTS

B1620/21

Diagnostic trouble codes

DESCRIPTION

The driver side - side airbag sensor circuit consists of the safing sensor, the diagnostic circuit, the lateral deceleration sensor, etc.
If the center airbag sensor assembly receives signals from the lateral deceleration sensor, it determines whether or not the SRS should be activated.
DTC B1620/21 is recorded when a malfunction is detected in the driver side - side airbag sensor circuit.
DTC No.
 DTC Detection Condition
 Trouble Area
B1620/21
  1. The center airbag sensor assembly receives an open circuit signal in the driver side - side airbag sensor circuit for 2 seconds.
  2. Driver side rear airbag sensor malfunction
  3. Driver side - side airbag sensor malfunction
  4. Center airbag sensor assembly malfunction
  1. Floor wire No. 2
  2. Driver side rear airbag sensor
  3. Driver side - side airbag sensor
  4. Center airbag sensor assembly

HINT:
Troubleshoot DTC B1620/21 first when DTC B1620/21 and B1630/23 are output simultaneously.


WIRING DIAGRAM

C114780E07

INSPECTION PROCEDURE


1. CHECK DTC

  1. C114835E01
    Turn the engine switch on (IG), and wait for at least 60 seconds.

  1. Clear the DTCs stored in the memory (Click here).

  1. Turn the engine switch off.

  1. Turn the engine switch on (IG), and wait for at least 60 seconds.

  1. Check for DTCs (Click here).

    OK:
    DTC B1620/21 is not output.

    HINT:
    Codes other than DTC B1620/21 may be output at this time, but they are not related to this check.



 NG
Go to step 2
OK

USE SIMULATION METHOD TO CHECK

2. CHECK CONNECTION OF CONNECTORS

  1. Turn the engine switch off.

  1. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.

  1. Check that the connectors are properly connected to the driver side - side airbag sensor and the driver side rear airbag sensor.

    OK:
    The connectors are properly connected.



 NG
CONNECT CONNECTORS, THEN GO TO STEP 1
OK


3. CHECK FLOOR WIRE NO. 2 (OPEN)

  1. C114836E05
    Disconnect the connectors from the driver side - side airbag sensor and the driver side rear airbag sensor.

  1. LHD:Using a service wire, connect Q10-2 (BBL+) and Q10-1 (BBL-) of connector "C".

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

  1. RHD:Using a service wire, connect P5-2 (BBR+) and Q10-1 (BBR-) of connector "C".

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

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

    Standard resistance:
    LHD:
    Tester connection
    		 Condition
    		 Specified condition
    Q15-1 (BBL+) - Q15-2 (BBL-)
    		 Always
    		 Below 1 Ω
    RHD:
    Tester connection
    		 Condition
    		 Specified condition
    P11-2 (BBR+) - P11-1 (BBR-)
    		 Always
    		 Below 1 Ω



NG
REPAIR OR REPLACE FLOOR WIRE NO. 2
OK


4. CHECK DRIVER SIDE - SIDE AIRBAG SENSOR

  1. C114837E01
    Disconnect the service wire from connector "C".

  1. Connect the connector to the driver side rear airbag sensor.

  1. Interchange the driver side - side airbag sensor with the front passenger side - side airbag sensor and connect the connectors to them.

  1. Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.

  1. Turn the engine switch on (IG), and wait for at least 60 seconds.

  1. Clear the DTCs stored in the memory (Click here).

  1. Turn the engine switch off.

  1. Turn the engine switch on (IG), and wait for at least 60 seconds.

  1. Check for DTCs (Click here).

    Result:
    Result
    		 Proceed to
    DTC B1620/21 is output.
    		 A
    DTC B1625/22 is output.
    		 B
    DTC B1620/21 and B1625/22 are not output.
    		 C

    HINT:
    Codes other than DTC B1620/21 and B1625/22 may be output at this time, but they are not related to this check.



 A
Go to step 5

B
REPLACE DRIVER SIDE - SIDE AIRBAG SENSOR
C

USE SIMULATION METHOD TO CHECK

5. CHECK DRIVER SIDE REAR AIRBAG SENSOR

  1. C114837E03
    Turn the engine switch off.

  1. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.

  1. Return the front passenger side - side airbag sensor and driver side - side airbag sensor to their original positions and connect the connectors to them.

  1. Interchange the driver side rear airbag sensor with the front passenger side rear airbag sensor and connect the connectors to them.

  1. Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.

  1. Turn the engine switch on (IG), and wait for at least 60 seconds.

  1. Clear the DTCs stored in the memory (Click here).

  1. Turn the engine switch off.

  1. Turn the engine switch on (IG), and wait for at least 60 seconds.

  1. Check for DTCs (Click here).

    Result:
    Result
    		 Proceed to
    DTC B1620/21 is output.
    		 A
    DTC B1625/22 is output.
    		 B
    DTC B1620/21 and B1625/22 are not output.
    		 C

    HINT:
    Codes other than DTC B1620/21 and B1625/22 may be output at this time, but they are not related to this check.



 A
REPLACE CENTER AIRBAG SENSOR ASSEMBLY

B
REPLACE DRIVER SIDE REAR AIRBAG SENSOR
C

USE SIMULATION METHOD TO CHECK


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