What does it mean?
B1877 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Driver-Side Pre-Tensioner Seat Belt Circuit Resistance High .
Symptoms
- Air bag warning lamp on continuously with the engine running
- Driver belt pretensioner is disabled and will not tighten in a collision
- Other restraint functions may be inhibited while the fault is stored
- Warning chime or restraint system message on vehicles with a driver information display
- Fault can appear intermittently when the seat is slid forward or back
Likely causes
- Under seat restraint connector not fully latched, or its yellow locking clip not pushed home after seat work
- Pin fretting and corrosion in the pretensioner connector, often after the floor carpet has been wet
- Harness stretched or broken where it follows the seat rails through its full travel
- Internal open in the pretensioner igniter (squib)
- Damaged terminal after the connector was probed with a sharp test lead
- Wiring damaged during aftermarket seat heater, seat cover or child seat anchor installation
- Restraint control module connector or internal driver fault
How to fix it
- Observe air bag safety procedure: ignition off, battery disconnected, prescribed stand time completed before touching any restraint connector
- Note whether the code is current or historic, and try to reproduce it by adjusting the seat while the system is monitored
- Unlatch and inspect the under seat connector for a partly seated housing, an unlocked retaining clip, corrosion, moisture or bent pins
- Clean and reseat the connector, then clear the code and test again before doing anything else
- Measure the loop resistance with an approved restraint circuit meter and compare it with the specified range, never with an ordinary ohmmeter on a live squib
- Repair a broken conductor only with the specified terminals and crimp method, not with a twisted splice or solder alone
- Consider the restraint control module last, after connector, harness and pretensioner have all been proven good