Toyota Check Engine Code
P0301 on Toyota
Cylinder 1 Misfire Detected
Also covers: Lexus, Scion
P0301 on Toyota: what makes it different
P0301 signals a misfire specifically on cylinder 1, a frequent complaint across Toyota's four-cylinder and V6 lineup where coil-on-plug ignition components and long-service-interval spark plugs are common wear points.
Most-affected engines
- 2AZ-FE 2.4L (Camry, RAV4, Scion tC)
- 1MZ-FE/3MZ-FE 3.0L/3.3L V6 (Camry, Sienna, Avalon, Highlander)
- 2GR-FE 3.5L V6 (Camry, Highlander, Sienna, Avalon)
Common model years: 2002–2015
Most likely cause on Toyota
A failing ignition coil on cylinder 1, often paired with a worn or carbon-fouled spark plug that hasn't been serviced at the recommended interval.
Known Toyota engine-family issues
Toyota's coil-on-plug ignition system is generally reliable, but oil seepage from valve cover gaskets on V6 engines is a known long-term issue that can contaminate coils and trigger cylinder-specific misfires. High-mileage 2.4L and V6 engines also commonly need spark plug replacement well past 100k miles.
Toyota-specific causes (most common first)
- Ignition coil breakdown from age and underhood heat
- Worn or gap-widened spark plug on cylinder 1 (common when platinum plugs go past their service life)
- Valve cover gasket oil leak dripping onto the ignition coil, causing tracking/misfire on V6 engines
- Carbon-tracked or cracked coil boot allowing spark to arc instead of firing the plug
- Fuel injector clog or weak spray pattern on that cylinder
- Low compression from carbon buildup on intake valves (common on direct-injection Toyota engines)
Toyota-specific diagnostic tip
Swap the cylinder 1 ignition coil with a coil from another cylinder and clear codes — if the misfire follows the swapped coil, you've confirmed a bad coil rather than a plug or injector issue.
Symptoms drivers report
- Check engine light (often flashing)
- Rough idle
- Loss of power
- Vibration at idle
Typical repair cost on Toyota
Most Toyota owners fix P0301 for between $120 and $550, depending on which underlying cause turns out to be at fault. Start with the most-likely cause for your vehicle — A failing ignition coil on cylinder 1, often paired with a worn or carbon-fouled spark plug that hasn't been serviced at the recommended interval. — before throwing parts at it.
Toyota P0301 FAQ
Why does Toyota specifically flag cylinder 1 so often?
Cylinder 1 is typically closest to the front of the engine and often runs slightly hotter, which accelerates coil and plug wear compared to other cylinders.
Can I just replace the spark plug and clear the code?
You can try, but if the coil is also degraded it will misfire again quickly — inspect both the plug and coil boot for carbon tracking before reassembling.
Is P0301 dangerous to drive with on a Toyota?
Occasional misfires are usually safe short-term, but sustained misfiring can damage the catalytic converter, so it's worth fixing within a few days.
Related codes
Drive a different make? See the general P0301 guide for cross-vehicle causes and symptoms.
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Most common fix for P0301:
Spark plugs & ignition coilsAs an Amazon Associate, AXLY earns from qualifying purchases. General P0301 guide →