DTC B1877, B1885

id080200803600


System Malfunction Location

•  DTC B1877: Driver-side pre-tensioner front buckle circuit resistance high
•  DTC B1885: Driver-side pre-tensioner front buckle 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.
•  The SAS control module monitors the driver-side pre-tensioner front buckle circuit resistance. If the SAS control module detects resistance which is not within the specification, it will output a pattern 46 flash to the air bag system warning light and store DTC B1877 or B1855 in memory.

Possible Cause

•  Resistance between the SAS control module and the driver-side pre-tensioner front buckle is not within the specification
•  Resistance at the driver-side pre-tensioner front buckle is not within the specification
•  SAS control module internal malfunction

Diagnostic Procedure

STEP

INSPECTION

ACTION
1
Turn the ignition switch to the LOCK position.
Connect the M-MDS.
Turn the ignition switch to the ON position.
Using the M-MDS, verify the DTCs and record the past malfunction DTCs.
Is the present malfunction DTC B1869 or B1855 displayed?
Yes
Note
•  Indicates a hard malfunction. The malfunction is still present. This malfunction cannot be cleared until it is corrected and the DTC is no longer displayed.
Go to the next step.
No
Intermittent malfunction. The malfunction is not present at this time. Go to Step 4.
2
Verify the following PIDs using the M-MDS.
(See PID/DATA MONITOR TABLE.)
―  DR_PTENS
Is driver-side pre-tensioner front buckle resistance normal?
―  Resistance: 1.7—3.2 ohms
Note
•  Measure the resistance while shaking the wiring harness between the driver-side pre-tensioner front buckle and SAS control module.
Yes
Go to the next step.
No
Replace the SAS control module. (See SAS CONTROL MODULE REMOVAL/INSTALLATION.)
After replacement, go to Step 5.
3
Warning
•  Handling the components improperly can accidentally deploy the air bags and pre-tensioner front buckle, which may seriously injure you. Read the service warnings and cautions before handling the SRS air bag system components.
Turn the ignition switch to the LOCK position.
Refer to the air bag system deactivation procedure and deactivate the system.
Turn the ignition switch to the ON position.
Verify the following PIDs using the M-MDS.
(See PID/DATA MONITOR TABLE.)
―  DR_PTENS
Is driver-side pre-tensioner front buckle resistance normal?
―  Resistance: 1.7—3.2 ohms
Note
•  Measure the resistance while shaking the wiring harness between the driver-side pre-tensioner front buckle and SAS control module.
Yes
Repair the related wiring harness. After repair, go to Step 5.
No
Replace the driver-side pre-tensioner front buckle.
(See FRONT BUCKLE REMOVAL/INSTALLATION.)
After replacement, go to Step 5.
4
Refer to the past malfunction DTCs recorded during Step 1.
Are the past malfunction DTCs displayed during Step 1 intermittent malfunctions which are not displayed as present malfunction DTCs?
Yes
Inspect for an intermittent short to the power supply between the SAS control module and the driver-side pre-tensioner front buckle. Attempt to replicate the malfunction by flexing the wiring harness and cycling the ignition key between the ON and LOCK position repeatedly. Repair or replace if there is any intermittent malfunction.
After repair or replacement, go to the next step.
No
Go to the next step.
5
Refer to the past malfunction DTCs recorded during Step 1.
Was any past malfunction DTC displayed during Step 1?
Yes
If any DTC is displayed, refer to the DTC table, and repair the malfunctioning part according to the DTC inspection.
No
Refer to the reactivation procedure in the air bag system deactivation procedure, reactivate the system. Clear all DTCs.