AIRBAG SYSTEM, Diagnostic DTC:B1900/73, B1901/73, B1902/73, B1903/73

DTC Code	DTC Name
B1900/73	Short in Front Driver Side Pretensioner Squib Circuit
B1901/73	Open in Front Driver Side Pretensioner Squib Circuit
B1902/73	Short to GND in Front Driver Side Pretensioner Squib Circuit
B1903/73	Short to B+ in Front Driver Side Pretensioner Squib Circuit

DESCRIPTION

The driver side front pretensioner circuit consists of the center airbag sensor and the front seat outer belt driver side. The circuit instructs the SRS to deploy when deployment conditions are met. These DTCs are recorded when a malfunction is detected in the driver side front pretensioner circuit.

DTC No.	DTC Detection Condition	Trouble Area
B1900/73	When one of following conditions is met: Center airbag sensor assembly receives line short circuit signal 5 times in driver side front pretensioner circuit during primary check Front pretensioner driver side malfunction Center airbag sensor assembly malfunction	Front seat outer belt assembly driver side (driver side front pretensioner) Center airbag sensor assembly Floor wire
B1901/73	When one of following conditions is met: Center airbag sensor assembly receives open circuit signal in driver side front pretensioner circuit for 2 seconds Front pretensioner driver side malfunction Center airbag sensor assembly malfunction	Front seat outer belt assembly driver side (driver side front pretensioner) Center airbag sensor assembly Floor wire
B1902/73	When one of following conditions is met: Center airbag sensor assembly receives short circuit to ground signal in driver side front pretensioner circuit for 0.5 seconds Front pretensioner driver side malfunction Center airbag sensor assembly malfunction	Front seat outer belt assembly driver side (driver side front pretensioner) Center airbag sensor assembly Floor wire
B1903/73	When one of following conditions is met: Center airbag sensor assembly receives short circuit to B+ signal in driver side front pretensioner circuit for 0.5 seconds Front pretensioner driver side malfunction Center airbag sensor assembly malfunction	Front seat outer belt assembly driver side (driver side front pretensioner) Center airbag sensor assembly Floor wire

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

CHECK FRONT SEAT OUTER BELT ASSEMBLY DRIVER SIDE (DRIVER SIDE FRONT PRETENSIONER)
1. Turn the ignition switch OFF.
2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
3. Disconnect the connector from the front seat outer belt driver side.
4. Connect the white wire side of SST (resistance 2.1 Ω) to the floor wire connector C.
  
  SST
  
  09843-18060
  
  CAUTION:
  
  Never connect a tester to the driver side front pretensioner 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.
  - Insert SST straight into the terminals of the connector.
5. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
6. Turn the ignition switch ON, and wait for at least 60 seconds.
7. Clear the DTCs Click here.
8. Turn the ignition switch OFF.
9. Turn the ignition switch ON, and wait for at least 60 seconds.
10. Check for DTCs Click here.
  
  OK
  
  DTC B1900, B1901, B1902, B1903 or 73 is not output.
  
  Tech Tips
  
  DTCs other than DTC B1900, B1901, B1902, B1903 or 73 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 DRIVER SIDE (DRIVER SIDE FRONT PRETENSIONER)
CHECK CONNECTOR
1. Turn the ignition switch OFF.
2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
3. Disconnect SST (resistance 2.1 Ω) from the floor wire.
4. Check that the floor wire connector (on the front seat outer belt driver side) is not damaged.
  
  OK
  
  The lock button is not disengaged, or the claw of the lock is not deformed or damaged.
NG
REPLACE FLOOR WIRE

OK

OK
DTC B1900, B1901, B1902, B1903 or 73 is not output.

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

CHECK FLOOR WIRE

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

Measure the voltage of the wire harness side connector.

Standard voltage

for LHD
Tester Connection	Switch Condition	Specified Condition
F50-1(PD+) - Body ground	Ignition switch ON	Below 1 V
F50-2(PD-) - Body ground	Ignition switch ON	Below 1 V

for RHD
Tester Connection	Switch Condition	Specified Condition
F51-1(PD+) - Body ground	Ignition switch ON	Below 1 V
F51-2(PD-) - Body ground	Ignition switch ON	Below 1 V

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

Measure the resistance of the wire harness side connector.

Standard resistance

for LHD
Tester Connection	Condition	Specified Condition
F50-1(PD+) - F50-2(PD-)	Always	Below 1 Ω
F50-1(PD+) - Body ground	Always	1 MΩ or higher
F50-2(PD-) - Body ground	Always	1 MΩ or higher

for RHD
Tester Connection	Condition	Specified Condition
F51-1(PD+) - F51-2(PD-)	Always	Below 1 Ω
F51-2(PD-) - Body ground	Always	1 MΩ or higher
F51-1(PD+) - Body ground	Always	1 MΩ or higher

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

Measure the resistance of the wire harness side connector.

Standard resistance

for LHD
Tester Connection	Condition	Specified Condition
F50-1(PD+) - F50-2(PD-)	Always	1 MΩ or higher

for RHD
Tester Connection	Condition	Specified Condition
F51-1(PD+) - F51-2(PD-)	Always	1 MΩ or higher

REPLACE FLOOR WIRE

REPLACE CENTER AIRBAG SENSOR ASSEMBLY