DTC B1617: Front Airbag Sensor Lost Communication (LH); DTC B1618: Front Airbag Sensor Initialization Error (LH) [08/2019 - ]: Procedure

1. Turn the ignition switch off.
2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
3. Check that the connectors are properly connected to the airbag sensor assembly and front airbag sensor LH.

   OK

   The connectors are properly connected.

Result: 

NG 

CONNECT CONNECTORS PROPERLY 

Result: 

OK 

See step  2

1. Disconnect the connectors from the airbag sensor assembly and front airbag sensor LH.
2. Check that the connectors (on the airbag sensor assembly side and front airbag sensor LH side) are not damaged.

   OK

   The connectors are not deformed or damaged.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   TEXT IN ILLUSTRATION
   
   

   *1	Front Airbag Sensor LH
   *2	Airbag Sensor Assembly

Result: 

NG 

REPLACE HARNESS AND CONNECTOR 

Result: 

OK 

See step  3

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   TEXT IN ILLUSTRATION
   
   

   *1	Front Airbag Sensor LH	*2	Airbag Sensor Assembly
   *3	Connector E	*4	Connector B
   *5	Service Wire	-	-
   *a	Front view of wire harness connector (to Front Airbag Sensor LH)	*b	Rear view of wire harness connector (to Airbag Sensor Assembly)

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

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   A13-2 (+SL) - Body ground	Ignition switch ON	Below 1 V
   A13-1 (-SL) - Body ground	Ignition switch ON	Below 1 V

3. Turn the ignition switch off.
4. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
5. Using a service wire, connect terminals 30 (+SL) and 28 (-SL) of connector B.
   NOTE:

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

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A13-2 (+SL) - A13-1 (-SL)	Always	Below 1 Ω

7. Disconnect the service wire from connector B.
8. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A13-2 (+SL) - A13-1 (-SL)	Always	1 MΩ or higher
   A13-2 (+SL) - Body ground	Always	1 MΩ or higher
   A13-1 (-SL) - Body ground	Always	1 MΩ or higher

Result: 

NG 

See step  5

Result: 

OK 

See step  4

1. Connect the connectors to the airbag sensor assembly.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

2. Interchange the front airbag sensor LH with RH and connect the connectors to them.
3. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
4. Turn the ignition switch to ON, and wait for at least 60 seconds.
5. Clear the DTCs stored in memory (Refer to DTC CHECK / CLEAR [08/2019 - ] ).
6. Turn the ignition switch off.
7. Turn the ignition switch to ON, and wait for at least 60 seconds.
8. Check for DTCs (Refer to DTC CHECK / CLEAR [08/2019 - ] ).
   RESULT
   
   

   Result	Proceed to
   DTC B1617 or B1618 is output	A
   DTC B1612 or B1613 is output	B
   DTC B1612, B1613, B1617 and B1618 are not output	C

   HINT: 

   Codes other than DTC B1612, B1613, B1617 and B1618 may be output at this time, but they are not related to this check.

   TEXT IN ILLUSTRATION
   
   

   *1	Front Airbag Sensor RH
   *2	Airbag Sensor Assembly

Result: 

A 

REPLACE AIRBAG SENSOR ASSEMBLY 

(Refer to REMOVAL [08/2015 - ] )

Result: 

B 

REPLACE FRONT AIRBAG SENSOR LH 

(Refer to REMOVAL [08/2015 - ] )

Result: 

C 

USE SIMULATION METHOD TO CHECK 

(Refer to DIAGNOSIS SYSTEM [08/2019 - ] )

1. Disconnect the instrument panel wire connector from the engine room main wire.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   TEXT IN ILLUSTRATION
   
   

   *1	Front Airbag Sensor LH	*2	Airbag Sensor Assembly
   *3	Engine Room Main Wire	*4	Instrument Panel Wire
   *5	Connector C	*6	Connector B
   *7	Service Wire	-	-
   *a	Front view of wire harness connector (to Engine Room Main Wire)	*b	Rear view of wire harness connector (to Airbag Sensor Assembly)

2. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   FA4-3 (+SL) - Body ground	Ignition switch ON	Below 1 V
   FA4-4 (-SL) - Body ground	Ignition switch ON	Below 1 V

4. Turn the ignition switch off.
5. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
6. Using a service wire, connect terminals 30 (+SL) and 28 (-SL) of connector B.
   NOTE:

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

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   FA4-3 (+SL) - FA4-4 (-SL)	Always	Below 1 Ω

8. Disconnect the service wire from connector B.
9. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   FA4-3 (+SL) - FA4-4 (-SL)	Always	1 MΩ or higher
   FA4-3 (+SL) - Body ground	Always	1 MΩ or higher
   FA4-4 (-SL) - Body ground	Always	1 MΩ or higher

Result: 

OK 

REPLACE ENGINE ROOM MAIN WIRE 

Result: 

NG 

REPLACE INSTRUMENT PANEL WIRE