What does it mean?
B1830 is a Body (airbags, seat belts, body electronics) fault code. It indicates: All Doors Unlock Control Circuit Performance .
Symptoms
- Some doors unlock while others stay locked or need a second attempt
- Unlock is noticeably slower or noisier than it used to be
- Grinding or straining noise from one door during unlock
- Code sets every time the unlock command is used
- Occasional battery drain if an actuator remains energised
Likely causes
- One lock actuator motor drawing high current because its brushes or gears are worn
- Lock linkage dry, frozen or bent, so the actuator has to work against extra load
- High resistance in the unlock output wire from corroded terminals or a poor splice
- Water damage inside one of the door harnesses
- One actuator seized so the module sees a stalled load
- Module output driver degraded and no longer supplying full current
- Aftermarket central locking module loading the same output
How to fix it
- Command unlock and listen at each door to identify the slow or noisy one
- Measure the current on the unlock output during a complete cycle
- Perform a voltage drop test on the output wire while the actuators run
- Unplug the suspect actuator, cycle unlock again and see whether the code stays away
- Free and lubricate the lock linkage, especially after cold or wet weather
- Replace the failing lock actuator and repeat the current measurement
- Repair corroded connectors, and replace the module only when the load is proven normal