CarFaultIQ

P0301

P0301 — Cylinder 1 Misfire

Updated By CarFaultIQ Editorial Team

Verify with official recall databases, service records, a mechanic inspection, and local market data before relying on this summary.

At a glance

Quick diagnostic answer

Cylinder 1 is misfiring, which can stem from ignition, fuel, or mechanical causes.

SeverityHigh UrgencyUrgency not yet verified EvidenceSource notes available
OBD code
P0301
System/category
Ignition & Misfire
Severity
High
Structured severity term
Urgency
Urgency not yet verified
Can I drive?
Drive with caution
Drive with caution and limit trips until it has been inspected; have it checked promptly. If the check-engine light is flashing, reduce speed and load and get it checked promptly: an active misfire can damage the catalytic converter.
Repair/cost band
$$ · Moderate
Typically a moderate repair; compare a couple of written quotes before authorizing work.
Vehicle applicability
Reported across many makes and models; not specific to one vehicle.
Current applicability note is free text

Computed rule output may be more cautious than stored content and is never used to soften safety-critical risks.

Short answer

P0301 commonly indicates cylinder 1 is misfiring, which can stem from ignition, fuel, or mechanical causes. Scan the live data and confirm the root cause with a qualified mechanic before replacing parts.

SeverityHighDrive?Drive with cautionRepairProfessional

Key takeaways

  • P0301 relates to: Cylinder 1 Misfire
  • Start with the cheapest, most likely checks first.
  • Drive with caution and limit trips until it has been inspected; have it checked promptly.
  • Confirm with live scan data before buying parts.

Can I still drive with this?

Drive with caution

Drive with caution and limit trips until it has been inspected; have it checked promptly. If the check-engine light is flashing, reduce speed and load and get it checked promptly: an active misfire can damage the catalytic converter.

SeverityHigh

High

Diagnostic flow

  1. What it meansCylinder 1 is misfiring, which can stem from ignition, fuel, or mechanical…
  2. Check this firstSwap/test the coil and plug for cylinder 1
  3. Likely causeFailing coil or spark plug
  4. Can you drive?Drive with caution

P0301 commonly indicates cylinder 1 is misfiring, which can stem from ignition, fuel, or mechanical causes. Scan the live data and confirm the root cause with a qualified mechanic before replacing parts.

Diagnostic-code summaries are informational — confirm with a scan tool and a qualified mechanic.

Structured DTC reference

What P0301 means

Cylinder 1 is misfiring

A trouble code identifies the circuit or monitored condition that failed its test. It does not, by itself, identify the failed part or prove the same cause on every vehicle.

Cause categories to discriminate

  • Failed ignition coil
  • Blocked fuel injector
  • Failed fuel injector
  • Failed ignition lead
  • Fouled spark plug
  • Worn spark plug

These are structured diagnostic hypotheses, not a parts-replacement list. Vehicle context, symptoms, operating conditions, and test results determine which remain supported.

Severity and drivability

The code alone is not enough to assign one universal severity or “safe to drive” answer. Stop driving for loss of braking or steering, severe overheating, oil-pressure loss, a fuel leak or fire risk, or any rapidly worsening safety symptom.

Add the symptom contextChoose the vehicle

What it means

Cylinder 1 is misfiring, which can stem from ignition, fuel, or mechanical causes.

Common symptoms

  • A rough idle or stumble
  • Flashing check-engine light under load

Likely causes

  • Failing coil or spark plug
  • Injector or compression issue

Diagnosis steps

  1. Swap/test the coil and plug for cylinder 1
  2. Check the injector and wiring
  3. Test compression if misfire persists

What a mechanic should check

Confirm the fault with live data and follow code-specific diagnostics before replacing parts.

Vehicle applicability

Reported across many makes and models; not specific to one vehicle.

Repair actions / cost band

$$ · Moderate

Typically a moderate repair; compare a couple of written quotes before authorizing work.

P0301 — vehicles with official records naming this code

P0301 is named in NHTSA-published manufacturer communications or investigations for 126 vehicle families, including:

  • Honda Odyssey model years 1999-2003, 2008-2017 · 110 records
  • Honda Pilot model years 2003, 2006-2015 · 78 records
  • Honda Accord model years 1995-2002, 2005, 2008-2012 · 52 records
  • Audi A6 model years 2005-2013, 2019-2021 · 27 records
  • Audi Q7 model years 2008-2013, 2020-2021 · 19 records
  • Audi A7 model years 2012-2013, 2019-2021 · 14 records
  • Audi S5 model years 2008-2013 · 13 records
  • Acura TL model years 1999-2003 · 12 records

A code named in a manufacturer communication means the document refers to it for those vehicles. It is not a diagnosis of any car, and it does not mean the code is common on that vehicle.

Frequently asked questions

What does P0301 mean?

Cylinder 1 is misfiring, which can stem from ignition, fuel, or mechanical causes.

Is it safe to drive with P0301?

Drive with caution and limit trips until it has been inspected; have it checked promptly.

What's the cheapest thing to check first?

Swap/test the coil and plug for cylinder 1.

Continue exploring

Related codes

Known faults that trigger this code

Related symptoms

Keep going

Next diagnostic step

Check warning lights Use the dashboard light to decide what to do now. Trace the symptom Match what you can see, hear, smell, or feel. Find vehicle coverage Check model-year problem windows and related faults.

Source & evidence notes

  • Code title: the generic OBD-II definition (SAE J2012) as held in the CarFaultIQ reference tables; not re-checked against the paywalled SAE text.
  • Regulatory context: California Code of Regulations Title 13 section 1968.2 sets on-board diagnostic requirements for misfire monitoring, including the flashing malfunction indicator lamp for a misfire that could damage the catalytic converter. It establishes what the vehicle must monitor, not the causes listed on this page. https://www.law.cornell.edu/regulations/california/13-CCR-1968.2
  • Likely causes and checks are CarFaultIQ editorial technical guidance. They have not been independently verified against manufacturer service information.
  • Always confirm specifics with live scan data, the owner manual or service information for your vehicle, and a qualified mechanic before replacing parts.