What does it mean?
B1863 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Passenger Window Position Sensor Power Supply Low .
Symptoms
- Auto up and auto down lost on the passenger window
- Anti-pinch protection disabled or the glass reverses near the top
- Window position needs to be relearned again and again
- Sensor pulse count or position missing on the scan tool
- Passenger window slower or less consistent than the driver window
Likely causes
- Supply wire shorted to ground inside the passenger door
- Position sensor in the passenger window motor shorted and loading the supply
- Corroded motor connector after water has entered the door
- Chafed harness in the passenger door hinge boot
- High resistance in the supply wire from a poor crimp or corroded terminal
- Module supply regulator sagging under load
- Extra load added to the circuit by aftermarket wiring
How to fix it
- Measure the supply voltage at the passenger motor connector with the ignition on
- Unplug the sensor and remeasure, a recovery means the sensor is loading the circuit
- With the module unplugged, ohm the supply wire to ground to find an external short
- Perform a voltage drop test to expose high resistance in the feed
- Check the door for water, a torn vapour barrier and blocked drains
- Repair the boot wiring and renew corroded terminals
- Replace the motor with the integrated sensor and carry out the window relearn