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DTC code page

P0301: Cylinder 1 Misfire Detected

Quick answer: The ECU detected misfire events concentrated in cylinder 1.

Drivers also search this fault as cylinder 1 misfire, misfire cylinder 1, number 1 cylinder misfire.

Severity: high Family: powertrain Related paths: 6
Meaning

What P0301 usually means

P0301 is a cylinder-specific misfire code. Unlike P0300, it gives you a narrower starting point: the control module sees the misfire pattern tied primarily to cylinder 1.

Fast triage

Start here before chasing parts

  • Scan first: save freeze-frame and pending codes before clearing anything.
  • Confirm the complaint: compare the stored code with current drivability symptoms.
  • Use context: trims, live data, and related codes usually narrow the fault faster than guesswork.
  • Work simplest to hardest: leaks, connectors, maintenance items, and known patterns before expensive components.
Initial checks

What to check first

  • Inspect the cylinder 1 plug and coil boot for wear, oil, coolant contamination, or carbon tracking.
  • If the engine layout allows it, swap the coil or plug with another cylinder and see whether the misfire follows.
Driving risk

Can you keep driving?

Brief gentle driving may be possible if the engine is stable, but a flashing MIL or severe shaking means stop and diagnose soon.

High urgency: If symptoms are active, reduce driving and diagnose quickly before secondary damage builds.
Likely causes

Common causes behind this code

  • Bad spark plug on cylinder 1
  • Weak coil or poor coil connector contact
  • Injector issue affecting cylinder 1 fuel delivery
  • Compression loss from valve, ring, or head gasket problem
  • Localized intake leak near cylinder 1 runner

Cause phrases often tied to this code: spark plug, ignition coil, injector, compression loss, intake leak.

Diagnostic order

Suggested workflow

  1. Inspect the cylinder 1 spark plug for fouling, gap, or oil contamination.
  2. Swap the coil with another cylinder if the design allows and see whether the misfire follows.
  3. Check injector pulse and listen for injector operation before replacing it.
  4. Confirm compression if ignition and fuel checks do not explain the fault.
Avoid guesswork

Common mistakes

  • Assuming every cylinder-specific misfire is a bad coil without checking the plug and connector.
  • Skipping compression testing after ignition checks come back clean.
Repair path

Practical fix guidance

  • Repair the failed ignition, fuel, air, or mechanical cause affecting cylinder 1.
  • Re-test under the same load or temperature that triggered the original misfire.
Vehicle context

Affected brands in this MVP

Brand hubs help broaden internal linking now and can evolve into make-specific diagnostic notes later.

Aliases and common searches

English phrases tied to P0301

Useful when the driver knows the wording but not the exact DTC yet.

  • cylinder 1 misfire
  • misfire cylinder 1
  • number 1 cylinder misfire
Related search intent

Queries this page can answer naturally

  • P0301 code meaning
  • what does P0301 mean
  • cylinder 1 not firing
FAQ

Quick questions about P0301

Is P0301 always ignition-related?

No. Ignition is common, but injector or compression issues can also trigger it.

Can I keep driving with P0301?

Only briefly and gently if the engine is stable. If the MIL flashes or the engine shakes badly, diagnose it quickly.