DTC B2777, B2778, B2779, B2780

id080200803000

DTC

B2777

Passenger‐side curtain air bag module circuit resistance low

B2778

Passenger‐side curtain air bag module circuit resistance high

B2779

Passenger‐side curtain air bag module circuit short to body ground

B2780

Passenger‐side curtain air bag module circuit short to power supply
DETECTION CONDITION
Warning
•  Detection conditions are for understanding the DTC outline before performing an inspection. Performing an inspection according to only the detection conditions may cause injury due to an operating error, or damage the system. When performing an inspection, always follow the inspection procedure.
•  Abnormal resistance (other than 1.4—3.2 ohms) detected in the passenger-side curtain air bag module circuit
•  Malfunction in the wiring harness between the passenger-side curtain air bag module and SAS control module
POSSIBLE CAUSE
•  Passenger-side curtain air bag module connector malfunction
•  Passenger-side curtain air bag module malfunction
•  Open circuit or short to ground in the wiring harness between the passenger-side curtain air bag module and SAS control module
•  Open circuit or power supply short in the wiring harness between the passenger-side curtain air bag module and SAS control module
•  SAS control module malfunction

Diagnostic procedure

Step

Inspection

Action
1
INSPECT PASSENGER-SIDE CURTAIN AIR BAG MODULE CONNECTOR
•  Turn the ignition switch to the LOCK position.
•  Disconnect the negative battery cable and wait for 1 min or more.
•  Remove the following parts:
―  A-pillar trim (See A-PILLAR TRIM REMOVAL/INSTALLATION.)
―  Rear seat (See REAR SEAT REMOVAL/INSTALLATION.)
―  Tire house trim (See TIRE HOUSE TRIM REMOVAL/INSTALLATION.)
―  Rear pillar trim (See REAR PILLAR TRIM REMOVAL/INSTALLATION.)
―  Headliner (See HEADLINER REMOVAL/INSTALLATION.)
•  Disconnect the passenger-side curtain air bag module connector. (See CURTAIN AIR BAG MODULE REMOVAL/INSTALLATION.)
•  Is there any malfunction of the passenger-side curtain air bag module connector?
Yes
Replace the passenger-side curtain air bag module wiring harness.
No
Go to the next step.
2
INSPECT PASSENGER-SIDE CURTAIN AIR BAG MODULE
•  Connect the SST (Fuel and thermometer checker) or apply 2-ohm resistance to the passenger-side curtain air bag module connector terminals A–B.
•  Set the SST (Fuel and thermometer checker) to 2 ohm.
•  Connect the negative battery cable.
•  Perform the DTC inspection for the SAS control module using the M-MDS.
•  Are DTCs B2777, B2778, B2779 and/or B2780 displayed?
Yes
Go to the next step.
No
Replace the passenger-side curtain air bag module. (See CURTAIN AIR BAG MODULE REMOVAL/INSTALLATION.)
3
INSPECT WIRING HARNESS BETWEEN SAS CONTROL MODULE AND PASSENGER-SIDE CURTAIN AIR BAG MODULE
•  Turn the ignition switch to the LOCK position.
•  Disconnect the negative battery cable and wait for 1 min or more.
•  Disconnect the SST (Fuel and thermometer checker) or the 2 ohm resistance.
•  Disconnect all SAS control module connectors.
•  Inspect the wiring harnesses between SAS control module connector terminal 1O and passenger-side curtain air bag module connector terminal A, and SAS control module connector terminal 1M and passenger-side curtain air bag module connector terminal B for the following:
―  Short to body ground
―  Open circuit
Note
•  Inspect for continuity while shaking the wiring harness between the SAS control module and passenger-side curtain air bag module.
•  Is the wiring harness normal?
Yes
Go to the next step.
No
Replace the wiring harness between the SAS control module and the passenger-side curtain air bag module.
4
INSPECT THE WIRING HARNESS BETWEEN THE SAS CONTROL MODULE AND PASSENGER-SIDE CURTAIN AIR BAG MODULE FOR A SHORT CIRCUIT TO THE POWER SUPPLY
•  Connect the negative battery cable.
•  Turn the ignition switch to the ON position.
•  Measure the voltage of SAS control module connector terminals 2D and 2A.
Note
•  Measure the voltage while shaking the wiring harness between the SAS control module and passenger-side curtain air bag module.
•  Is the voltage measured?
Yes
Replace the wiring harness between the SAS control module and the passenger-side curtain air bag module.
No
Go to the next step.
5
INSPECT DTCs
•  Disconnect the negative battery cable and wait for 1 min or more.
•  Connect the disconnected connector.
•  Connect the negative battery cable.
•  Clear DTCs using the M-MDS.
•  Verify DTCs using the M-MDS.
•  Is DTC B2777, B2778, B2779 and/or B2780 displayed again?
•  Are there other DTCs output?
Yes
Replace the SAS control module.
(See SAS CONTROL MODULE REMOVAL/INSTALLATION.)
No
DTC troubleshooting completed.