The engine computer has pinpointed the misfire to cylinder 1 specifically — unlike the random/multiple misfire code, this one is isolated to a single cylinder, which usually points to something local to that cylinder rather than an engine-wide problem.
Symptoms
- A distinct, rhythmic shake or pulse felt through the engine, worse at idle
- Rough idle that smooths out somewhat at higher RPM
- Reduced power and slightly worse fuel economy
- Check engine light on, sometimes flashing during the misfire
Likely causes
- Faulty spark plug or ignition coil on cylinder 1 — the most common single-cylinder cause
- A clogged or failing fuel injector on that cylinder
- Low compression in cylinder 1 (worn piston rings or a leaking valve)
- A damaged or disconnected spark plug wire (on wire-type ignition systems)
How to diagnose it
- Swap the coil and spark plug from cylinder 1 with another cylinder — if the misfire follows the swap, the part is confirmed bad
- Check injector function (resistance test or listen for the injector's click with a mechanic's stethoscope)
- Run a compression or leak-down test on cylinder 1 if the ignition/fuel components check out fine
Typical fixes & cost
- Replace the spark plug and/or ignition coil for cylinder 140–180 EUR
- Clean or replace the cylinder 1 fuel injector100–350 EUR
- Engine repair for low compression (valve or ring work) — only if compression test confirms it500–2500 EUR
Code names are compiled from open/standardized SAE and ISO references. Explanations, symptoms, causes and fixes are original. Covers generic (P0/C0/B0/U0) codes only — manufacturer-specific codes are planned for a future update.
AS
Reviewed by Artyom SemenovAutomotive Editor · Fact-checked by Yauheni Kapliarchuk, Editor-in-Chief