P0301 on a Toyota Corolla
P0301 means cylinder 1 Misfire Detected. On the Corolla, a few causes come up far more than others.
What P0301 usually means on a Corolla
P0301 tells you the Corolla is misfiring specifically on cylinder 1. Being cylinder-specific, it's usually a quick fix isolated to that hole's coil, plug, or injector. On early 1ZZ-FE cars, oil consumption can foul whichever plug is weakest, and that's often where a single-cylinder code starts. It feels like a light shimmy at idle and may flash the light under acceleration.
Most common causes on the Corolla
- Failed coil on cylinder 1
Swap the No.1 coil with an adjacent one; if the miss moves, the coil is the problem.
- Fouled or worn plug
A single oil- or carbon-fouled plug on cylinder 1 is a cheap, common cause.
- Injector fault
A clogged or leaking injector starves or floods that cylinder.
- Low compression on cylinder 1
A worn ring or valve on a high-mileage 1ZZ-FE shows as a persistent single-cylinder miss.
What P0301 costs to fix on a Corolla
This is about as inexpensive as engine repairs get on a Corolla — one coil and one plug, both quick to reach on the little four. The only way the bill grows is if a compression test reveals internal wear, which points to ring or valve work rather than a bolt-on.
Year, engine and mileage change the answer. Start a case and Redline weighs these causes against what your car shows, then names the check that would settle it.
Other codes on the Toyota Corolla
Related symptoms
Toyota Corolla problems & recalls by year
Based on widely reported patterns for this model; individual causes vary by year, engine and history. Generic P0301 behavior is covered on the main P0301 page. Confirm with a scan tool before buying parts.
P0301 on your Corolla?
Every problem becomes a Case. Tell Redline what your Corolla is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.