What does it mean?
B1421 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Side-airbag module (RH) (squib) system fault 2 (open in the squib circuit) .
Symptoms
- Airbag warning lamp lit continuously with the side restraint disabled
- Right side airbag will not deploy in an impact even though nothing looks disturbed
- Fault sets right after the seat has been removed, refitted or moved on its rails
- Code can be intermittent, appearing only when the seat is adjusted to a certain position
- No other electrical or driving symptom
Likely causes
- Under seat connector unplugged or not fully seated after seat removal or servicing
- Broken conductor in the harness that flexes every time the seat is slid forward and back
- Terminal backed out of the connector body so the pin no longer makes contact
- Corroded terminals from moisture in the seat base, leaving a high resistance joint
- Open initiator inside the side airbag module built into the seat
- Repair splice or extension in the yellow harness with a poor crimp
- Restraint control module measuring channel failure
How to fix it
- Turn the ignition off, disconnect the battery and wait the specified discharge time before going near the connectors
- Locate the yellow under seat connector, unplug it, inspect for backed-out pins, corrosion and spread terminals, then refit until it clicks
- Slide the seat through its full travel with the connector visible and look for a harness that pulls tight or catches on the rail
- Clear the code after reseating and see whether the fault returns, since this alone repairs many cases
- If the fault remains, connect the manufacturer approved load tool in place of the airbag module to establish whether the open is in the harness or the module
- Repair or renew the damaged harness section and secure it so it cannot be trapped by the seat mechanism
- Replace the side airbag module if the load tool proves the wiring is sound, then clear the memory and verify the lamp goes out