P0301 on a Hyundai Elantra
P0301 means cylinder 1 Misfire Detected. On the Elantra, a few causes come up far more than others.
What P0301 usually means on a Elantra
P0301 isolates a misfire to cylinder 1 on the Elantra. The first suspects are the coil and plug on that cylinder, easily checked by swapping the coil to a neighbor and seeing whether the misfire moves. An injector fault on cylinder 1 is next. If ignition and fuel check out and the cylinder shows low compression, that points to a mechanical problem, which on some Elantra engines can tie into the known internal-wear complaints and warrants a proper compression or leak-down test.
Most common causes on the Elantra
- Coil or plug on cylinder 1
Swap-test the coil; if the misfire follows it, the coil is the cause and the fix is cheap.
- Cylinder 1 fuel injector
A clogged or failing injector starves that cylinder and imitates an ignition fault.
- Low compression on cylinder 1
A burnt valve or internal wear shows as a mechanical misfire that ignition parts will not cure.
- Localized vacuum leak
A leak near that cylinder's intake runner can lean it enough to misfire.
What P0301 costs to fix on a Elantra
An ignition fix on cylinder 1 is inexpensive, usually under a couple hundred dollars in parts and labor. If a leak-down reveals low compression from internal wear, the repair is far larger, and you should check for applicable Hyundai warranty or recall coverage before authorizing engine work. Testing before buying parts keeps you from replacing good components.
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 Hyundai Elantra
Related symptoms
Hyundai Elantra 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 Elantra?
Every problem becomes a Case. Tell Redline what your Elantra 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.