P0301 Hyundai Elantra
Cylinder 1 Misfire Detected · Powertrain Code · High · Repair: Easy
What is P0301?
Misfire detected in cylinder 1. Typically caused by a worn spark plug, bad ignition coil, faulty fuel injector, or low compression in that cylinder.
When the Hyundai Elantra triggers code P0301 (cylinder 1 misfire detected), it typically points to an issue in the powertrain system. This is a high severity code, so address it promptly to avoid further damage or safety concerns. Below you'll find the most common causes, symptoms, and repair options specific to the Hyundai Elantra.
This repair is rated easy, meaning basic tools, no lift needed.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Hyundai Elantra.
Common Causes on Hyundai Elantra
- Ignition coil failure on cylinder 1 on 2.0L/2.5L Smartstream or 1.6T
- Spark plug fouled from GDI carbon deposit migration
- GDI fuel injector carbon buildup causing poor spray pattern on cylinder 1
- Low compression from Theta II engine bearing or valve damage (recall related)
Symptoms
- Rough idle with noticeable engine vibration
- Engine shaking or vibration especially at idle
- Loss of power during acceleration
- Check engine light flashing (indicating catalytic converter damage risk)
- Poor fuel economy from unburned fuel
- Unburned fuel smell from exhaust
Notes for Hyundai Elantra
Hyundai/Kia GDI engines need regular spark plug changes at 30K-mile intervals.