DTC B1877, B1878, B1879, B1885 [AIR BAG SYSTEM]

id0802a0801400

System Malfunction Location

DTC	System Malfunction Location
M-MDS display
B1877	Driver-side pre-tensioner seat belt circuit open circuit or 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.

Possible Causes

System Wiring Diagram

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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. (See AIR BAG SYSTEM SERVICE WARNINGS.) (See AIR BAG SYSTEM SERVICE CAUTIONS.) •  Turn the ignition switch to the LOCK position. •  Remove the battery cover. •  Disconnect the negative battery cable and wait for 1 min or more. (See BATTERY REMOVAL/INSTALLATION [L8, LF].) •  Remove the back trim. (See BACK TRIM REMOVAL/INSTALLATION.) •  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 CONTROL MODULE AND DRIVER-SIDE PRE-TENSIONER SEAT BELT •  Remove the column cover. (See COLUMN COVER REMOVAL/INSTALLATION.) •  Disconnect the clock spring connector. (See CLOCK SPRING REMOVAL/INSTALLATION.) •  Remove the glove compartment. (See GLOVE COMPARTMENT REMOVAL/INSTALLATION.) •  Disconnect the passenger-side air bag module connector. (See PASSENGER-SIDE AIR BAG MODULE REMOVAL/INSTALLATION.) •  Disconnect the driver and passenger-side seat connectors. (See SEAT REMOVAL/INSTALLATION.) •  Remove the passenger-side pre-tensioner seat belt connectors. (See SEAT BELT REMOVAL/INSTALLATION.) •  Remove the console panel. (See CONSOLE PANEL REMOVAL/INSTALLATION.) •  Disconnect the SAS control module connectors. (See SAS CONTROL MODULE REMOVAL/INSTALLATION.) •  Inspect the wiring harnesses between SAS control module connector terminal 2D and driver-side pre-tensioner seat belt connector terminal A, and SAS control module connector terminal 2A and driver-side pre-tensioner seat belt connector terminal B for the following: ―  Short circuit between terminals ―  Short to body ground ―  Open circuit 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.
3	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 connector and driver-side pre-tensioner seat belt connector disconnected. •  Measure the voltage of SAS control module connector terminals 2A and 2D. 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.
4	INSPECT DRIVER-SIDE PRE-TENSIONER SEAT BELT •  Turn the ignition switch to the LOCK position. •  Disconnect the negative battery cable and wait for 1min 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 the DTC for the SAS control module using the M-MDS. (See CLEARING DTC [AIR BAG SYSTEM].) •  Perform the DTC inspection for the SAS control module using the M-MDS. •  (See DTC INSPECTION [AIR BAG SYSTEM].) •  Are the same DTCs present?	Yes	Go to the next step.
		No	Replace the driver-side pre-tensioner seat belt. (See SEAT BELT REMOVAL/INSTALLATION.)
5	PERFORM SAS CONTROL MODULE DTC INSPECTION •  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. •  Turn the ignition switch to the ON position. •  Clear the DTC for the SAS control module using the M-MDS. (See CLEARING DTC [AIR BAG SYSTEM].) •  Perform the DTC inspection for the SAS control module using the M-MDS. (See DTC INSPECTION [AIR BAG SYSTEM].) •  Are the same DTCs present?	Yes	Replace the SAS control module. (See SAS CONTROL MODULE REMOVAL/INSTALLATION.)
		No	DTC troubleshooting completed.