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 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—3.1 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 unit
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 unit
•  Driver-side pre-tensioner seat belt malfunction
•  SAS unit malfunction

Diagnostic Procedure

Step

Inspection

Action
1
INSPECT DRIVER-SIDE PRE-TENSIONER SEAT BELT CONNECTOR
Warning
•  Handling the component parts improperly can accidentally operate (deploy) the air bag module, which may seriously injure you. Read the service warnings/cautions and the workshop manual 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 driver-side rear door lower trim.
•  Disconnect the driver-side pre-tensioner seat belt connector.
•  Inspect the driver-side pre-tensioner seat belt connector. (Corrosion, damage, and disconnected pins)
•  Is there any malfunction of the driver-side pre-tensioner seat belt connector?
Yes
Replace the driver-side pre-tensioner seat belt wiring harness.
No
Go to the next step.
2
INSPECT WIRING HARNESS BETWEEN SAS UNIT AND DRIVER-SIDE PRE-TENSIONER SEAT BELT
•  Remove the column cover.
•  Disconnect the clock spring connector.
•  Remove the glove compartment.
•  Disconnect the passenger-side air bag module connector.
•  Disconnect the driver and passenger-side curtain air bag module connectors.
•  Disconnect the driver and passenger-side side air bag module connectors.
•  Remove the rear door lower trim.
•  Disconnect the passenger-side pre-tensioner seat belt connector.
•  Partially peel back the floor covering.
•  Disconnect the SAS unit connector.
•  Inspect the wiring harnesses between SAS unit connector terminal 2S and driver-side pre-tensioner seat belt connector terminal A, and SAS unit 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 unit 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 unit and the driver-side pre-tensioner seat belt.
3
INSPECT THE WIRING HARNESS BETWEEN THE SAS UNIT 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 unit connector and driver-side pre-tensioner seat belt connector disconnected.
•  Measure the voltage of SAS unit connector terminals 2S and 2P of SAS unit harness side connector.
Note
•  Measure the voltage while shaking the wiring harness between the SAS unit and driver-side pre-tensioner seat belt.
•  Is the voltage measured?
Yes
Replace the wiring harness between the SAS unit and the driver-side pre-tensioner seat belt.
No
Go to the next step.
4
INSPECT 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.
•  Connect the SST (Fuel and thermometer checker) or apply 2 ohms resistance to the driver-side pre-tensioner seat belt connector terminals A and B.
•  Set the SST (Fuel and thermometer checker) to 2 ohms.
•  Except for the driver-side pre-tensioner seat belt connector, reconnect all disconnected connectors.
•  Connect the negative battery cable.
•  Turn the ignition switch to the ON position.
•  Clear DTCs using the WDS or eguivalent. (See CLEARING DTC.)
•  Perform the DTC inspection for the SAS unit using the M-MDS. (See DTC DISPLAY.)
•  Are the same DTCs present?
Yes
Go to the next step.
No
Replace the driver-side pre-tensioner seat belt.
(See FRONT SEAT BELT REMOVAL/INSTALLATION.)
5
INSPECT DTCs
•  Turn the ignition switch to the LOCK position.
•  Disconnect the negative battery cable and wait for 1min or more.
•  Disconnect the SST (Fuel and thermometer checker) or the 2 ohms resistance.
•  Connect the driver-side pre-tensioner seat belt connector.
•  Connect the negative battery cable.
•  Clear DTCs using the WDS or eguivalent. (See CLEARING DTC.)
•  Perform the DTC inspection for the SAS unit using the WDS or eguivalent. (See DTC DISPLAY.)
•  Are the same DTCs present?
Yes
Replace the SAS unit.
(See SAS UNIT REMOVAL/INSTALLATION.)
No
DTC troubleshooting completed.