P0301 on a Toyota Highlander
P0301 means cylinder 1 Misfire Detected. On the Highlander, a few causes come up far more than others.
What P0301 usually means on a Highlander
P0301 isolates the misfire to cylinder 1 on a Highlander, which usually makes it a targeted fix on that cylinder's coil, plug, or injector. On the V6s cylinder 1 is on the front (radiator-side) bank, so it's more reachable than a rear-bank cylinder. You'll typically feel a faint shudder at idle, and hard acceleration may set the light flashing.
Most common causes on the Highlander
- Failed coil on cylinder 1
Move the No.1 coil to an adjacent cylinder; if the misfire follows, that coil is the fault.
- Worn or fouled plug
A single overdue or oil-fouled plug on cylinder 1 is a cheap, common cause.
- Injector fault
An injector that's clogged or leaking will under- or over-fuel just that cylinder.
- Low compression on cylinder 1
A worn valve or ring on a high-mileage V6 shows as a persistent single miss.
What P0301 costs to fix on a Highlander
Cylinder 1 sits on the accessible front bank of the Highlander V6, so a coil-and-plug fix here stays inexpensive without pulling the intake. The 2AZ-FE four is easy too. Only a low compression reading turns it into internal-engine work.
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 Highlander
Related symptoms
Toyota Highlander 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 Highlander?
Every problem becomes a Case. Tell Redline what your Highlander 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.