AIRBAG SYSTEM, Diagnostic DTC:B1656/38

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

DESCRIPTION

The seat belt buckle switch LH circuit consists of the center airbag sensor assembly 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.

DTC Code	Detection Condition	Trouble Area
B1656/38	One of the following conditions is met: The center airbag sensor assembly 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. Front seat inner belt LH malfunction Center airbag sensor assembly malfunction	No. 2 floor wire Front seat inner belt assembly LH (Seat belt buckle switch LH) Center airbag sensor assembly

DTC Code

Detection Condition

Trouble Area

B1656/38

One of the following conditions is met:

The center airbag sensor assembly 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.
Front seat inner belt LH malfunction
Center airbag sensor assembly malfunction

No. 2 floor wire
Front seat inner belt assembly LH (Seat belt buckle switch LH)
Center airbag sensor assembly

WIRING DIAGRAM

INSPECTION PROCEDURE

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.

PROCEDURE

CHECK FOR DTC
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 B1656/38 is not output.
  
  Tech Tips
  
  Codes other than DTC B1656/38 may be output at this time, but they are not related to this check.
NG
CHECK CONNECTION OF CONNECTORS Click here

OK

USE SIMULATION METHOD TO CHECK Click here
CHECK CONNECTION OF CONNECTORS
1. Turn the engine switch off.
2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3. Check that the connectors are properly connected to the center airbag sensor assembly 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 assembly and the front seat inner belt LH.
2. Check that the connectors (on the center airbag sensor assembly side and front seat inner belt LH side) are not damaged.
  
  OK
  
  The connectors are not deformed or damaged.
NG
REPLACE NO. 2 FLOOR WIRE

OK

OK
DTC B1656/38 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 ASSEMBLY - FRONT SEAT INNER BELT LH)

Connect the negative (-) terminal cable to the battery, 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
S17-1 (LBE+) - Body ground	Engine switch on (IG)	Below 1 V
S17-3 (LBE-) - Body ground	Engine switch on (IG)	Below 1 V

Turn the engine switch off.
Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.

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

Standard resistance

Tester Connection	Condition	Specified Condition
S17-1 (LBE+) - S8-10 (LBE+)	Always	Below 1 Ω

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

Standard resistance

Tester Connection	Condition	Specified Condition
S17-1 (LBE+) - Body ground	Always	1 MΩ or higher
S17-3 (LBE-) - Body ground	Always	Below 1 Ω

REPLACE NO. 2 FLOOR WIRE

CHECK FRONT SEAT INNER BELT LH
1. Connect the connector to the center airbag sensor assembly and the front seat inner belt LH.
2. Connect the negative (-) terminal cable to the battery, 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 B1656/38 is not output.
  
  Tech Tips
  
  Codes other than DTC B1656/38 may be output at this time, but they are not related to this check.
NG
REPLACE FRONT SEAT INNER BELT LH Click here

OK

USE SIMULATION METHOD TO CHECK Click here
REPLACE FRONT SEAT INNER BELT LH
1. Turn the engine switch off.
2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3. Replace the front seat inner belt LH Click here.
  
  Tech Tips
  
  Perform inspection using parts from a normal vehicle if possible.
NEXT
CHECK CENTER AIRBAG SENSOR ASSEMBLY
1. Connect the negative (-) terminal cable to the battery, 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 B1656/38 is not output.
  
  Tech Tips
  
  Codes other than DTC B1656/38 may be output at this time, but they are not related to this check.
NG
REPLACE CENTER AIRBAG SENSOR ASSEMBLY Click here

OK

REPLACE FRONT SEAT INNER BELT ASSEMBLY LH Click here