The computer detects that the 1 cylinder is leaking - the fuel in it is not burning normally. The last digit of the code is the cylinder number.
High. If the “Check Engine” lamp is flashing, stop. The unburnt fuel reaches the catalytic converter and overheats it.
Gasoline engines most often. Spark plug, coil, nozzle, valves, compression.
What does P0301 mean
The computer monitors the crankshaft revolutions and senses when a cylinder is not firing. When the gaps are in cylinder 1, it records P0301. The same for cylinders 2, 3 and 4 is P0302, P0303 and P0304, and for several cylinders at the same time — P0300.
The good news is that the code points to a specific cylinder - so the search is faster.
Symptoms
- The engine shakes, mostly at idle
- Loss of power
- Flashing or steady light "Check Engine"
- Increased fuel consumption and smell
| Can it be driven?
If the light blinks, no. If it's on all the time and the car runs relatively smoothly, drive carefully to the garage.
Common reasons
- Worn spark plug in cylinder 1.
- Faulty coil — the quick check is to swap with the coil on an adjacent cylinder and see if the fault "moves".
- Clogged or leaking nozzle on cylinder 1.
- Vacuum leak near the cylinder — manifold gasket.
- Low compression — burnt or non-sealing valve, worn segments, burnt head gasket.
How we diagnose it
- We're looking at the outage counter by cylinder in real time.
- We exchange the coil and the candle with another cylinder — if the error moves, the cause has been found.
- We check the nozzle and look for a vacuum leak.
- If everything is fine — we measure the compression and do a leak test from the cylinder.