What does it mean?
P1381 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Misfire Detected - No Communication with Brake Control Module .
Symptoms
- MIL on, frequently with ABS and traction control warning lamps
- Rough running and a clear misfire feel
- Speedometer dropping out or reading zero
- ABS and traction control disabled
- Hesitation and loss of power
Likely causes
- Loss of serial data communication between the engine module and the brake control module
- Brake control module without power: a blown fuse or a corroded connector
- Open, shorted or corroded data bus wiring and splice points
- Wheel speed sensor faults making the rough road data invalid
- Low system voltage or a weak battery disturbing network communication
- Another failed module loading the data bus down
- A genuine engine misfire present at the same time
How to fix it
- Scan every module on the vehicle, not just the engine, and record all communication codes
- Check the fuses, power and ground at the brake control module
- Inspect the data bus connectors and known splice points for corrosion and water
- Measure bus resistance and voltage levels to locate an open circuit or a short
- Verify all four wheel speed signals in live data
- Repair the communication fault first, clear the codes, then re-evaluate whether a real misfire remains
- If misfire counters still climb, diagnose cylinder by cylinder with spark, injector and compression tests