P0301 Honda Accord
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 Honda Accord 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 Honda Accord.
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 Honda Accord.
Common Causes on Honda Accord
- Ignition coil failure on cylinder 1 on 1.5T or 2.0T engine
- Spark plug fouled from fuel dilution in oil on 1.5T engines
- Fuel injector deposit buildup on GDI system causing lean misfire
- Low compression from valve recession on high-mileage engines
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 Honda Accord
Honda 1.5T fuel-in-oil dilution can foul plugs; check oil level and sniff for fuel on dipstick.