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

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

DESCRIPTION

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

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

These DTCs are recorded when a malfunction is detected in the front pretensioner squib RH circuit.

DTC Code	Detection Condition	Trouble Area
B1900/73	One of the following conditions is met: The center airbag sensor assembly receives a line short circuit signal 5 times in the front pretensioner squib RH circuit during the primary check. Front pretensioner squib RH malfunction Center airbag sensor assembly malfunction	Floor wire Front seat outer belt assembly RH (Front pretensioner squib RH) Center airbag sensor assembly
B1901/73	One of the following conditions is met: The center airbag sensor assembly receives an open circuit signal in the front pretensioner squib RH circuit for 2 seconds. Front pretensioner squib RH malfunction Center airbag sensor assembly malfunction	Floor wire Front seat outer belt assembly RH (Front pretensioner squib RH) Center airbag sensor assembly
B1902/73	One of the following conditions is met: The center airbag sensor assembly receives a short circuit to ground signal in the front pretensioner squib RH circuit for 0.5 seconds. Front pretensioner squib RH malfunction Center airbag sensor assembly malfunction	Floor wire Front seat outer belt assembly RH (Front pretensioner squib RH) Center airbag sensor assembly
B1903/73	One of the following conditions is met: The center airbag sensor assembly receives a short circuit to B+ signal in the front pretensioner squib RH circuit for 0.5 seconds. Front pretensioner squib RH malfunction Center airbag sensor assembly malfunction	Floor wire Front seat outer belt assembly RH (Front pretensioner squib RH) Center airbag sensor assembly

WIRING DIAGRAM

INSPECTION PROCEDURE

Note

After turning the power switch OFF, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work Click here.
When disconnecting the cable from the negative (-) auxiliary battery terminal while performing repairs, some systems need to be initialized after the cable is reconnected Click here.

Tech Tips

Perform the simulation method by selecting "check mode" (signal check) with the intelligent tester Click here.
After selecting "check mode" (signal check), perform the simulation method by wiggling each connector of the airbag system or driving the vehicle on various types of roads Click here.

PROCEDURE

CHECK FRONT SEAT OUTER BELT RH (FRONT PRETENSIONER SQUIB RH)
1. Turn the power switch OFF.
2. Disconnect the negative (-) terminal cable from the auxiliary battery, and wait for at least 90 seconds.
3. Disconnect the connectors from the front seat outer belt RH.
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 RH (front pretensioner squib RH) 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 negative (-) terminal cable to the auxiliary battery, and wait for at least 2 seconds.
6. Turn the power switch ON (IG), and wait for at least 60 seconds.
7. Clear the DTCs Click here.
8. Turn the power switch OFF.
9. Turn the power switch ON (IG), and wait for at least 60 seconds.
10. Check for DTCs Click here.
  
  OK
  
  DTC B1900, B1901, B1902 or B1903 is not output.
  
  Tech Tips
  
  Codes other than DTC B1900, B1901, B1902 and B1903 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 RH Click here
CHECK CONNECTOR
1. Turn the power switch OFF.
2. Disconnect the negative (-) terminal cable from the auxiliary battery, 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 RH 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 or B1903 is not output.

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

CHECK FLOOR WIRE (FRONT PRETENSIONER SQUIB RH CIRCUIT)

Disconnect the connectors from the center airbag sensor assembly.
Connect the negative (-) terminal cable to the auxiliary battery, and wait for at least 2 seconds.
Turn the power switch ON (IG).

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

Standard voltage

Tester Connection	Switch Condition	Specified Condition
R3-1 (R+) - Body ground	Power switch ON (IG)	Below 1 V
R3-2 (R-) - Body ground	Power switch ON (IG)	Below 1 V

Turn the power switch OFF.
Disconnect the negative (-) terminal cable from the auxiliary 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
R3-1 (R+) - R3-2 (R-)	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
R3-1 (R+) - R3-2 (R-)	Always	1 MΩ or higher
R3-1 (R+) - Body ground	Always	1 MΩ or higher
R3-2 (R-) - Body ground	Always	1 MΩ or higher

REPLACE FLOOR WIRE

CHECK CENTER AIRBAG SENSOR ASSEMBLY
1. Connect the connectors to the front seat outer belt RH and the center airbag sensor assembly.
2. Connect the negative (-) terminal cable to the auxiliary battery, and wait for at least 2 seconds.
3. Turn the power switch ON (IG), and wait for at least 60 seconds.
4. Clear the DTCs stored in the memory Click here.
5. Turn the power switch OFF.
6. Turn the power switch ON (IG), and wait for at least 60 seconds.
7. Check the DTCs Click here.
  
  OK
  
  DTC B1900, B1901, B1902 or B1903 is not output.
  
  Tech Tips
  
  Codes other than DTC B1900, B1901, B1902 and B1903 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