What does it mean?
P1306 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Cylinder Number 6 Random Misfire Detected . This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms
- MIL (check engine lamp) on, flashing during heavy misfire episodes
- Rough running that comes and goes with load, temperature or humidity
- Stumble and shaking when accelerating, noticeably smoother at steady cruise
- Fuel smell and increased consumption
- Occasional hesitation or a stall at idle after a cold start
Likely causes
- Spark plug 6 worn, fouled or with a gap opened up by mileage
- Ignition coil 6 breaking down only under load or when hot, or a cracked boot arcing intermittently
- Injector 6 partly restricted, sticking or with an intermittent connection
- Vacuum leak at the rear intake runner or a hardened injector seal that leaks when cold
- Heat or vibration sensitive wiring at coil or injector 6
- Low compression on cylinder 6 that only shows at certain loads
- Low fuel pressure or contaminated fuel causing random misfire counts across the engine
How to fix it
- Watch live misfire counters during a road test to confirm cylinder 6 and record the conditions that trigger the counts
- Read the freeze frame for load, rpm and coolant temperature at the moment the code set
- Swap coil 6 and then injector 6 with an adjacent cylinder and see whether the counts move
- Inspect the spark plug and boot for wear, carbon tracking and moisture
- Smoke test the intake at the rear of the manifold where leaks are easy to miss
- Check fuel pressure under load and inspect the injector spray pattern
- Compression test cylinder 6 if the ignition and fuel checks come back clean