B1881 - FAULT CODE - OBD2

B1881 Code failures by brands

B1881 FORD, LINCOLN, MAZDA, MERCURY: PASSENGER SEAT BELT PRETENSIONER CIRCUIT OPEN

Description of DTC code B1881

As part of the vehicle safety systems, manufacturers incorporate seat belts into their vehicles. The function of the seat belt is to reduce the likelihood of the occupants of the vehicle being thrown out of the windows or windshield after a collision. The belts used in vehicles are usually two- or three-point belts, which are combined in a system that, when an impact is detected, the belt holds the occupants tightly.

Belt pretensioners are a device that is used in cases where a frontal crash occurs so that the belt does not lengthen and can be adjusted to the body to keep it supported against the seat and backrest. The RCM (Restraint Control Module) is responsible for checking that all seat belt pretensioners are working properly.

DTC B1881 OBDII code is stored on Ford, Lincoln, Mazda, and Mercury vehicles when the RCM detects a low or open resistance in the passenger seat belt pretensioner circuit.

Symptoms of fault code B1881

Check Engine Lamp illuminated.
The airbag warning indicator remains illuminated.

Causes of OBD2 B1881

B1881 OBD2 diagnostic code is set by the following:

The seat belt passenger pretensioner circuit wiring may have been damaged.
The seat belt passenger pretensioner circuit may be open due to bad connections.
The passenger seat belt pretensioner may be defective.
The Restraint Control Module could be damaged.

Possible solutions of the DTC code B1881

To troubleshoot the B1881 OBDII fault code you must do the following:

Consult the Technical Service Bulletins as a first step.
Check that there is no damage to the cables and connectors of the seat belt passenger pretensioner circuit. Look for wear or corrosion damage and if such damage is found, proceed with repairs.
Measure the seat belt passenger pretensioner circuit voltages. These should match the values specified by the manufacturer. In the event that the actual values differ from those specified, check that this is not due to poor connections. Repair as required.
Check the passenger seat belt pretensioner for damage. For this diagnosis, you should refer to the steps outlined in the service manual. Correct it as applicable.