What does it mean?
B1864 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Passenger Window Position Sensor Power Supply High .
Symptoms
- Auto up and auto down no longer work on the passenger window
- Anti-pinch protection is disabled
- Position values on the scan tool are stuck at maximum or clearly wrong
- Window does not stop cleanly at the top of its travel
- Code sets again every time the window is used
Likely causes
- Supply wire shorted to battery voltage inside the door or at the module
- Wires crossed during a previous door, motor or regulator repair
- Corrosion or moisture bridging adjacent pins in the motor connector
- Module supply regulator failed high
- Aftermarket accessory feeding voltage back into the sensor circuit
- Damaged insulation in the hinge boot allowing contact with a powered wire
How to fix it
- Measure the supply with the sensor connector unplugged and the ignition on
- Unplug the module too, remaining battery voltage means an external short to power
- Use the driver side circuit as a healthy reference for comparison
- Inspect both connectors for corrosion or debris bridging the pins
- Check the door harness for aftermarket taps, speakers or alarm wiring
- Repair the shorted section of harness and renew any damaged terminals
- Replace the motor and sensor assembly or the module if the supply stays high, then relearn the window