AIRBAG SYSTEM, Diagnostic DTC:B1920/77, B1921/77, B1922/77, B1923/77

DTC Code	DTC Name
B1920/77	Short in Rear Pretensioner Squib RH Circuit
B1921/77	Open in Rear Pretensioner Squib RH Circuit
B1922/77	Short to GND in Rear Pretensioner Squib RH Circuit
B1923/77	Short to B+ in Rear Pretensioner Squib RH Circuit

DESCRIPTION

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

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

These DTCs are stored when a malfunction is detected in the rear pretensioner squib RH circuit.

DTC Code	DTC Detection Condition	Trouble Area
B1920/77	When one of the following conditions is met: The center airbag sensor receives a line short circuit signal 5 times in the rear pretensioner squib RH circuit during the primary check. A rear pretensioner squib RH malfunction. A center airbag sensor malfunction.	No. 2 floor wire Rear seat outer belt assembly RH (Rear pretensioner squib RH) Center airbag sensor assembly
B1921/77	When one of the following conditions is met: The center airbag sensor receives an open circuit signal in the rear pretensioner squib RH circuit for 2 seconds. A rear pretensioner squib RH malfunction. A center airbag sensor malfunction.	No. 2 floor wire Rear seat outer belt assembly RH (Rear pretensioner squib RH) Center airbag sensor assembly
B1922/77	When one of the following conditions is met: The center airbag sensor receives a short circuit to ground signal in the rear pretensioner squib RH circuit for 0.5 seconds. A rear pretensioner squib RH malfunction. A center airbag sensor malfunction.	No. 2 floor wire Rear seat outer belt assembly RH (Rear pretensioner squib RH) Center airbag sensor assembly
B1923/77	When one of the following conditions is met: The center airbag sensor receives a short circuit to B+ signal in the rear pretensioner squib RH circuit for 0.5 seconds. A rear pretensioner squib RH malfunction. A center airbag sensor malfunction.	No. 2 floor wire Rear seat outer belt assembly RH (Rear pretensioner squib RH) 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 REAR SEAT OUTER BELT RH (REAR PRETENSIONER SQUIB RH)
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 rear 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 rear seat outer belt RH (rear 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 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 stored in the memory 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 B1920, B1921, B1922 or B1923 is not output.
  
  Tech Tips
  
  Codes other than DTC B1920, B1921, B1922 and B1923 may be output at this time, but they are not related to this check.
NG
CHECK CONNECTORS Click here

OK

REPLACE REAR SEAT OUTER BELT ASSEMBLY RH Click here
CHECK CONNECTORS
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 No. 2 floor wire connector (on the rear seat outer belt RH side) is not damaged.
  
  OK
  
  The lock button is not disengaged, and the claw of the lock is not deformed or damaged.
NG
REPLACE NO. 2 FLOOR WIRE

OK

OK
DTC B1920, B1921, B1922 or B1923 is not output.

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

CHECK NO. 2 FLOOR WIRE (REAR PRETENSIONER SQUIB RH CIRCUIT)

Disconnect the connectors from the center airbag sensor.
Connect the cable to the negative (-) battery terminal, and wait for at least 90 seconds.

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

Standard Voltage

Tester Connection	Switch Condition	Specified Condition
L14-1 (RR+) - Body ground	Engine switch on (IG)	Below 1 V
L14-2 (RR-) - 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
L14-1 (RR+) - L14-2 (RR-)	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
L14-1 (RR+) - L14-2 (RR-)	Always	1 MΩ or higher
L14-1 (RR+) - Body ground	Always	1 MΩ or higher
L14-2 (RR-) - Body ground	Always	1 MΩ or higher

REPLACE NO. 2 FLOOR WIRE

CHECK CENTER AIRBAG SENSOR
1. Connect the connectors to the rear seat outer belt RH and the center airbag sensor.
2. Connect the cable to the negative (-) battery terminal, and wait for at least 90 seconds.
3. Turn the engine switch on (IG), and wait for at least 60 seconds.
4. Clear the DTCs stored in the memory 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 B1920, B1921, B1922 or B1923 is not output.
  
  Tech Tips
  
  Codes other than DTC B1920, B1921, B1922 and B1923 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