What does it mean?
B1726 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Curtain Airbag (CAB) Circuit Fault .
Symptoms
- Airbag warning lamp stays on and the curtain airbag is taken out of service
- Side curtain protection unavailable in a side impact or rollover
- Warning lamp may come and go over rough surfaces when the joint is loose
- Fault appears after interior trim, headliner or belt work in most cases
- Scan tool shows the circuit as open or out of range in live data
Likely causes
- Curtain squib connector left unplugged or only half latched after trim, headliner or seat belt work
- Fretting corrosion on the connector terminals from constant small vibration
- Broken conductor where the roof-rail loom bends at the pillar or over a bracket
- Terminal pushed out of the connector body during a careless disconnect
- Curtain inflator with an internally open squib element
- Water damage inside the pillar raising circuit resistance
- Restraint control module measuring circuit at fault
How to fix it
- Read all restraint codes and note whether this fault is current
- De-energise the system, disconnect the battery and observe the stand-down time
- Unclip the pillar trim and confirm every SRS connector is fully home and its lock engaged
- Inspect the terminals for corrosion, spread contacts or a pin pushed out of the housing
- Fit an approved load tool at the curtain connector; if the fault clears, the inflator is faulty
- If the fault stays with the load tool fitted, test the harness for continuity back to the module and repair any break
- Replace the curtain module or, as a final step, the restraint control module, then clear and verify