DTC B1877, B1878, B1879, B1885

id080200801400

DTC

B1877

Driver-side pre-tensioner seat belt circuit resistance high

B1878

Driver-side pre-tensioner seat belt circuit short to power supply

B1879

Driver-side pre-tensioner seat belt circuit short to body ground

B1885

Driver-side pre-tensioner seat belt circuit resistance low
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 1.5—3.7 ohms) detected in the driver-side pre-tensioner seat belt circuit
•  Malfunction in the wiring harness between the driver-side pre-tensioner seat belt and SAS control module
POSSIBLE CAUSE
•  Driver-side pre-tensioner seat belt connector malfunction
•  Open or short circuit in the wiring harness between the driver-side pre-tensioner seat belt and SAS control module
•  Driver-side pre-tensioner seat belt malfunction
•  SAS control module malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION
1
INSPECT DRIVER‐SIDE PRE-TENSIONER SEAT BELT CONNECTOR
Warning
•  Handling the air bag system components improperly can accidentally deploy the air bag modules and pre-tensioner seat belts, which may seriously injure you. Read the service warnings and cautions before handling the air bag system components.
•  Turn the ignition switch to the LOCK position.
•  Disconnect the negative battery cable and wait for 1 min or more.
•  Remove the B-pillar lower trim. (See B-PILLAR LOWER TRIM REMOVAL/INSTALLATION.)
•  Disconnect the driver-side pre-tensioner seat belt connector.
•  Is there any malfunction of the driver-side pre-tensioner seat belt connector?
Yes
Replace the air bag wiring harness.
No
Go to the next step.
2
VERIFY WHETHER MALFUNCTION IS IN DRIVER‐SIDE PRE-TENSIONER SEAT BELT OR RELATED WIRING HARNESS
•  Connect the leads of the SST (Fuel and thermometer checker) or apply 2-ohm resistance to driver-side pre-tensioner seat belt connector terminals A and B.
•  Set the resistance of the SST (Fuel and thermometer checker) to the 2-ohm position.
•  Connect the negative battery cable.
•  Turn the ignition switch to the ON position.
•  Are DTCs B1877, B1878, B1879 and/or B1885 indicated?
Yes
Go to the next step.
No
Replace the driver-side pre-tensioner seat belt.
(See FRONT SEAT BELT REMOVAL/INSTALLATION.)
3
INSPECT WIRING HARNESS BETWEEN SAS CONTROL MODULE AND DRIVER-SIDE PRE-TENSIONER SEAT BELT
•  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 2S and driver-side pre-tensioner seat belt connector terminal A, and SAS control module connector terminal 2P and driver-side pre-tensioner seat belt connector terminal B for the following:
―  Short to body ground
―  Open circuit
―  Short circuit between terminals
Note
•  Inspect for continuity while shaking the wiring harness between the SAS control module and driver-side pre-tensioner seat belt.
•  Is the wiring harness normal?
Yes
Go to the next step.
No
Replace the wiring harness between the SAS control module and the driver-side pre-tensioner seat belt.
4
INSPECT THE WIRING HARNESS BETWEEN THE SAS CONTROL MODULE AND DRIVER-SIDE PRE-TENSIONER SEAT BELT FOR A SHORT CIRCUIT TO THE POWER SUPPLY
•  Connect the negative battery cable.
•  Turn the ignition switch to the ON position with SAS control module and driver-side pre-tensioner seat belt connector disconnected.
•  Measure the voltage of SAS control module connector terminals 2S and 2P of SAS control module harness side connector.
Note
•  Measure the voltage while shaking the wiring harness between the SAS control module and driver-side pre-tensioner seat belt.
•  Is the voltage measured?
Yes
Replace the wiring harness between the SAS control module and the driver-side pre-tensioner seat belt.
No
Go to the next step.
5
INSPECT DTCs
•  Turn the ignition switch to the LOCK position.
•  Disconnect the negative battery cable and wait for 1 min or more.
•  Reconnect all disconnected connectors.
•  Connect the negative battery cable.
•  Turn the ignition switch to the ON position.
•  Clear DTCs using the M-MDS.
•  Verify DTCs using the M-MDS.
•  Are DTCs B1877, B1878, B1879 and/or B1885 indicated?
Yes
Replace the SAS control module.
(See SAS CONTROL MODULE REMOVAL/INSTALLATION.)
No
DTC troubleshooting completed.