AIRBAG SYSTEM, Diagnostic DTC:B1655/37, B1656/38

DTC Code	DTC Name
B1655/37	Seat Belt Buckle Switch RH Circuit Malfunction
B1656/38	Seat Belt Buckle Switch LH Circuit Malfunction

DESCRIPTION

for LHD:

The seat belt buckle switch LH circuit consists of the center airbag sensor and the front seat inner belt LH.

DTC B1656/38 is recorded when a malfunction is detected in the seat belt buckle switch LH circuit.

for RHD:

The seat belt buckle switch RH circuit consists of the center airbag sensor and the front seat inner belt RH. DTC B1655/37 is stored when a malfunction is detected in the seat belt buckle switch RH circuit.

for LHD
DTC Code	DTC Detection Condition	Trouble Area
B1656/38	When one of the following conditions is met: The center airbag sensor receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the seat belt buckle switch LH circuit for 2 seconds. A front seat inner belt LH malfunction. A center airbag sensor malfunction.	Floor wire Front seat inner belt assembly LH (Seat belt buckle switch LH) Center airbag sensor assembly

for RHD
DTC Code	DTC Detection Condition	Trouble Area
B1655/37	When one of the following conditions is met: The center airbag sensor receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the seat belt buckle switch RH circuit for 2 seconds. A front seat inner belt RH malfunction. A center airbag sensor malfunction.	No. 2 floor wire Front seat inner belt assembly RH (Seat belt buckle switch RH) Center airbag sensor assembly

WIRING DIAGRAM

for LHD
*1	Front Seat Inner Belt LH
*2	Center Airbag Sensor

for RHD
*1	Front Seat Inner Belt RH
*2	Center Airbag Sensor

CAUTION / NOTICE / HINT

Note

After turning the engine 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 Click here.
When disconnecting the cable from the negative (-) battery terminal while performing repairs, some systems need to be initialized after the cable is reconnected Click here.
After replacing the center airbag sensor assembly, refer to initialization Click here.

PROCEDURE

CHECK VEHICLE CONDITION

Check vehicle condition.

Result
Result	Proceed to
for LHD	A
for RHD	B

CHECK FOR DTC Click here

CHECK FOR DTC
*1 Front Seat Inner Belt LH

*2 Center Airbag Sensor
1. Turn the engine switch on (IG).
2. Clear the DTCs Click here.
3. Turn the engine switch off.
4. Turn the engine switch on (IG), and wait for at least 60 seconds.
5. Check for DTCs Click here.
  
  OK
  
  DTC B1656 is not output.
  
  Tech Tips
  
  Codes other than DTC B1656 may be output at this time, but they are not related to this check.
OK
USE SIMULATION METHOD TO CHECK Click here

NG
CHECK CONNECTION OF CONNECTORS
1. Turn the engine 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 center airbag sensor and front seat inner belt LH.
  
  OK
  
  The connectors are properly connected.
NG
CONNECT CONNECTORS PROPERLY

OK
CHECK CONNECTORS
1. Disconnect the connectors from the center airbag sensor and the front seat inner belt LH.
2. Check that the connectors (on the center airbag sensor side and front seat inner belt LH side) are not damaged.
  
  OK
  
  The connectors are not deformed or damaged.
NG
REPLACE FLOOR WIRE

OK

OK
DTC B1656 is not output.

OK
The connectors are properly connected.

OK
The connectors are not deformed or damaged.

CHECK FLOOR WIRE (CENTER AIRBAG SENSOR - FRONT SEAT INNER BELT LH)

Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
Turn the engine switch on (IG).

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

Standard Voltage

Tester Connection	Switch Condition	Specified Condition
K10-6 (LBE+) - Body ground	Engine switch on (IG)	Below 1 V
K10-7 (LBE-) - Body ground	Engine switch on (IG)	Below 1 V

Turn the engine switch off.
Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
Using a service wire, connector terminals 10 (LBE+) and 18 (LBE-) of connector B.

Note

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

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

Standard Resistance

Tester Connection	Condition	Specified Condition
K10-6 (LBE+) - K10-7 (LBE-)	Always	Below 1 Ω

Disconnect a service wire from connector B.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
K10-6 (LBE+) - K10-7 (LBE-)	Always	1 MΩ or higher
K10-6 (LBE+) - Body ground	Always	1 MΩ or higher
K10-7 (LBE-) - Body ground	Always	1 MΩ or higher

REPLACE FLOOR WIRE

CHECK FRONT SEAT INNER BELT LH (SEAT BELT BUCKLE SWITCH)
*1 Front Seat Inner Belt LH

*2 Center Airbag Sensor
1. Connect the connector to the center airbag sensor and the front seat inner belt LH.
2. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
3. Turn the engine switch on (IG), and wait for at least 60 seconds.
4. Clear the DTCs Click here.
5. Turn the engine switch off.
6. Turn the engine switch on (IG), and wait for at least 60 seconds.
7. Check for DTCs Click here.
  
  OK
  
  DTC B1656 is not output.
  
  Tech Tips
  
  Codes other than DTC B1656 may be output at this time, but they are not related to this check.
OK
USE SIMULATION METHOD TO CHECK Click here

NG
REPLACE FRONT SEAT INNER BELT ASSEMBLY LH
1. Turn the engine switch off.
2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
3. Replace the front seat inner belt LH Click here.
  
  Tech Tips
  
  Perform the inspection using parts from a normally functioning vehicle if possible.
NEXT
CHECK CENTER AIRBAG SENSOR
*1 Front Seat Inner Belt LH

*2 Center Airbag Sensor
1. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
2. Turn the engine switch on (IG), and wait for at least 60 seconds.
3. Clear the DTCs Click here.
4. Turn the engine switch off.
5. Turn the engine switch on (IG), and wait for at least 60 seconds.
6. Check for DTCs Click here.
  
  OK
  
  DTC B1656 is not output.
  
  Tech Tips
  
  Codes other than DTC B1656 may be output at this time, but they are not related to this check.
OK
REPLACE FRONT SEAT INNER BELT ASSEMBLY LH Click here

NG
REPLACE CENTER AIRBAG SENSOR ASSEMBLY Click here
CHECK FOR DTC
*1 Center Airbag Sensor

*2 Front Seat Inner Belt RH
1. Turn the engine switch on (IG), and wait for at least 60 seconds.
2. Clear the DTCs Click here.
3. Turn the engine switch off.
4. Turn the engine switch on (IG), and wait for at least 60 seconds.
5. Check for DTCs Click here.
  
  OK
  
  DTC B1655 is not output.
  
  Tech Tips
  
  Code other than DTC B1655 may be output at this time, but they are not related to this check.
OK
USE SIMULATION METHOD TO CHECK Click here

NG
CHECK CONNECTION OF CONNECTORS
1. Turn the engine 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 center airbag sensor and front seat inner belt RH.
  
  OK
  
  The connectors are properly connected.
NG
CONNECT CONNECTORS PROPERLY

OK
CHECK CONNECTORS
1. Disconnect the connectors from the center airbag sensor and the front seat inner belt RH.
2. Check that the connectors (on the center airbag sensor side and front seat inner belt RH side) are not damaged.
  
  OK
  
  The connectors are not deformed or damaged.
NG
REPLACE NO. 2 FLOOR WIRE

OK

OK
DTC B1656 is not output.

OK
DTC B1656 is not output.

*1	Center Airbag Sensor
*2	Front Seat Inner Belt RH

OK
DTC B1655 is not output.

OK
The connectors are properly connected.

OK
The connectors are not deformed or damaged.

CHECK NO. 2 FLOOR WIRE (CENTER AIRBAG SENSOR - FRONT SEAT INNER BELT RH)

Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
Turn the engine switch on (IG).

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

Standard Voltage

Tester Connection	Switch Condition	Specified Condition
L48-6 (RBE+) - Body ground	Engine switch on (IG)	Below 1 V
L48-7 (RBE-) - Body ground	Engine switch on (IG)	Below 1 V

Turn the engine switch off.
Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
Using a service wire, connector terminals 15 (RBE+) and 23 (RBE-) of connector B.

Note

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

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

Standard Resistance

Tester Connection	Condition	Specified Condition
L48-6 (RBE+) - L48-7 (RBE-)	Always	Below 1 Ω

Disconnect a service wire from connector B.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
L48-6 (RBE+) - L48-7 (RBE-)	Always	1 MΩ or higher
L48-6 (RBE+) - Body ground	Always	1 MΩ or higher
L48-7 (RBE-) - Body ground	Always	1 MΩ or higher

REPLACE NO. 2 FLOOR WIRE

CHECK FRONT SEAT INNER BELT RH (SEAT BELT BUCKLE SWITCH)
*1 Center Airbag Sensor

*2 Front Seat Inner Belt RH
1. Connect the connector to the center airbag sensor and the front seat inner belt RH.
2. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
3. Turn the engine switch on (IG), and wait for at least 60 seconds.
4. Clear the DTCs Click here.
5. Turn the engine switch off.
6. Turn the engine switch on (IG), and wait for at least 60 seconds.
7. Check for DTCs Click here.
  
  OK
  
  DTC B1655 is not output.
  
  Tech Tips
  
  Codes other than DTC B1655 may be output at this time, but they are not related to this check.
OK
USE SIMULATION METHOD TO CHECK Click here

NG
REPLACE FRONT SEAT INNER BELT ASSEMBLY RH
1. Turn the engine switch off.
2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
3. Replace the front seat inner belt RH Click here.
  
  Tech Tips
  
  Perform the inspection using parts from a normally functioning vehicle if possible.
NEXT
CHECK CENTER AIRBAG SENSOR
*1 Center Airbag Sensor

*2 Front Seat Inner Belt RH
1. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
2. Turn the engine switch on (IG), and wait for at least 60 seconds.
3. Clear the DTCs Click here.
4. Turn the engine switch off.
5. Turn the engine switch on (IG), and wait for at least 60 seconds.
6. Check for DTCs Click here.
  
  OK
  
  DTC B1655 is not output.
  
  Tech Tips
  
  Codes other than DTC B1655 may be output at this time, but they are not related to this check.
OK
REPLACE FRONT SEAT INNER BELT ASSEMBLY RH Click here

NG
REPLACE CENTER AIRBAG SENSOR ASSEMBLY Click here