AIRBAG SYSTEM, Diagnostic DTC:B1905/74, B1906/74, B1907/74, B1908/74

DTC Code	DTC Name
B1905/74	Short in Front Pretensioner Squib LH Circuit
B1906/74	Open in Front Pretensioner Squib LH Circuit
B1907/74	Short to GND in Front Pretensioner Squib LH Circuit
B1908/74	Short to B+ in Front Pretensioner Squib LH Circuit

DESCRIPTION

The front pretensioner squib LH circuit consists of the center airbag sensor and the front seat outer belt LH.

This circuit instructs the SRS to deploy when deployment conditions are met.

These DTCs are stored when a malfunction is detected in the front pretensioner squib LH circuit.

DTC Code	DTC Detection Condition	Trouble Area
B1905/74	When one of the following conditions is met: The center airbag sensor receives a line short circuit signal 5 times in the front pretensioner squib LH circuit during the primary check. A front pretensioner squib LH malfunction. A center airbag sensor malfunction.	Floor wire Front seat outer belt assembly LH (Front pretensioner squib LH) Center airbag sensor assembly
B1906/74	When one of the following conditions is met: The center airbag sensor receives an open circuit signal in the front pretensioner squib LH circuit for 2 seconds. A front pretensioner squib LH malfunction. A center airbag sensor malfunction.	Floor wire Front seat outer belt assembly LH (Front pretensioner squib LH) Center airbag sensor assembly
B1907/74	When one of the following conditions is met: The center airbag sensor receives a short circuit to ground signal in the front pretensioner squib LH circuit for 0.5 seconds. A front pretensioner squib LH malfunction. A center airbag sensor malfunction.	Floor wire Front seat outer belt assembly LH (Front pretensioner squib LH) Center airbag sensor assembly
B1908/74	When one of the following conditions is met: The center airbag sensor receives a short circuit to B+ signal in the front pretensioner squib LH circuit for 0.5 seconds. A front pretensioner squib LH malfunction. A center airbag sensor malfunction.	Floor wire Front seat outer belt assembly LH (Front pretensioner squib 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.

Tech Tips

To perform the simulation method, enter the check mode (signal check) with the intelligent tester Click here, and then wiggle each connector of the airbag system or drive the vehicle on various type of road Click here.

PROCEDURE

CHECK FRONT SEAT OUTER BELT LH (FRONT PRETENSIONER SQUIB LH)
1. Turn the engine switch off.
2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
3. Disconnect the connectors from the front seat outer belt LH.
4. Connect the white wire side of SST (resistance: 2.1 Ω) to connector C.
  
  CAUTION:
  
  Never connect the tester to the front seat outer belt LH (front pretensioner squib LH) for measurement, as this may lead to a serious injury due to airbag deployment.
  Note
  - Do not forcibly insert SST into the terminals of the connector when connecting SST.
  - Insert SST straight into the terminals of the connector.
  SST
  
  09843-18061
5. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
6. Turn the engine switch on (IG), and wait for at least 60 seconds.
7. Clear the DTCs Click here.
8. Turn the engine switch off.
9. Turn the engine switch on (IG), and wait for at least 60 seconds.
10. Check for DTCs Click here.
  
  OK
  
  DTC B1905, B1906, B1907 or B1908 is not output.
  
  Tech Tips
  
  Codes other than DTC B1905, B1906, B1907 and B1908 may be output at this time, but they are not related to this check.
NG
CHECK CONNECTOR Click here

OK

REPLACE FRONT SEAT OUTER BELT ASSEMBLY LH Click here
CHECK CONNECTOR
1. Turn the engine switch off.
2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
3. Disconnect SST from connector C.
4. Check that the floor wire connector (on the front seat outer belt LH side) is not damaged.
  
  OK
  
  The lock button is not disengaged, and the claw of the lock is not deformed or damaged.
NG
REPLACE FLOOR WIRE

OK

OK
DTC B1905, B1906, B1907 or B1908 is not output.

OK
The lock button is not disengaged, and the claw of the lock is not deformed or damaged.

CHECK FLOOR WIRE (FRONT PRETENSIONER SQUIB LH CIRCUIT)

Disconnect the connectors from the center airbag sensor.
Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

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

Standard Voltage

Tester Connection	Switch Condition	Specified Condition
K1-1 (L+) - Body ground	Engine switch on (IG)	Below 1 V
K1-2 (L-) - 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.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
K1-1 (L+) - K1-2 (L-)	Always	Below 1 Ω

Release the activation prevention mechanism built into connector B Click here.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
K1-1 (L+) - K1-2 (L-)	Always	1 MΩ or higher
K1-1 (L+) - Body ground	Always	1 MΩ or higher
K1-2 (L-) - Body ground	Always	1 MΩ or higher

REPLACE FLOOR WIRE

CHECK CENTER AIRBAG SENSOR
1. Connect the connectors to the front seat outer belt LH and the center airbag sensor.
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 B1905, B1906, B1907 or B1908 is not output.
  
  Tech Tips
  
  Codes other than DTC B1905, B1906, B1907 and B1908 may be output at this time, but they are not related to this check.
NG
REPLACE CENTER AIRBAG SENSOR ASSEMBLY Click here

OK

USE SIMULATION METHOD TO CHECK Click here