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P0301
System
Powertrain (Engine)
Scanner som krävs
Basic OBD2 code reader (engine codes, live data, smog readiness)

Cylinder 1 Misfire Detected

Understand P0301, common causes, and the right TOPDON scanner to diagnose it.

The ECU detected repeated misfires on cylinder 1 only. Unlike P0300 (random/multiple misfire), P0301 points to a specific cylinder — spark, fuel, or compression on that bore.

Vanliga symptom

  • Rough idle that may feel rhythmic
  • Loss of power under load
  • Check engine light (steady or flashing)
  • Possible fuel smell from unburned fuel

Typiska orsaker

  • Worn spark plug or failed ignition coil on cylinder 1
  • Clogged or leaking fuel injector for cylinder 1
  • Low compression on cylinder 1 (valve, ring, or head gasket)
  • Vacuum leak affecting one runner (intake gasket, cracked hose)
  • Loose or damaged coil-on-plug boot on cylinder 1

Vilken scanner behöver du?

Basic OBD2 code reader (engine codes, live data, smog readiness)

Använd live-data och freeze frame innan du byter delar. ABS-, SRS- och U-koder kräver oftast en fullsystems-scanner.

Diagnostiktips

  • Spara freeze frame när koden först sätts
  • Rensa koden först efter att orsaken är åtgärdad
  • Kontrollera relaterade väntande koder
  • Verifiera batterispänning över 12,4 V innan du misstänker sensorer

Rekommenderade TOPDON-scannrar

Vanliga frågor

What does P0301 mean?
P0301 indicates cylinder 1 misfire detected. The ECU detected repeated misfires on cylinder 1 only. Unlike P0300 (random/multiple misfire), P0301 points to a specific cylinder — spark, fuel, or compression on that bore.
Can I diagnose P0301 with a basic code reader?
Yes — P0301 is typically accessible with a basic OBD2 code reader like the TOPDON ArtiDiag201 or TopScan Lite. Live data helps confirm the repair.
Which TOPDON scanner do I need for P0301?
Basic OBD2 code reader (engine codes, live data, smog readiness) See recommended tools on this page.
Is it safe to drive with P0301?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.