P0301

Q: What does OBD2 code P0301 mean?

P0301 means: Cylinder 1 Misfire Detected. The ECM has detected a misfire in cylinder 1. A misfire means the air/fuel mixture in that cylinder is not igniting properly or not igniting at all.

Cylinder 1 Misfire Detected

The ECM has detected a misfire in cylinder 1. A misfire means the air/fuel mixture in that cylinder is not igniting properly or not igniting at all.

SeverityCritical

CategoryEngine

Est. Repair Cost$50–$300

Code TypePowertrain

DIY RepairYes

⚡ Common Causes

›Faulty spark plug on cylinder 1
›Bad ignition coil on cylinder 1
›Clogged or failed fuel injector on cylinder 1
›Low compression in cylinder 1

⚠️ Symptoms

›Rough idle especially at startup
›Hesitation on acceleration
›Possible fuel smell from exhaust
›Check engine light on or flashing

✅ How to Fix — Step by Step

Step 1:Swap spark plug from cylinder 1 to another and recheck
Step 2:Swap ignition coil to another cylinder
Step 3:Test injector with noid light
Step 4:Perform compression test on cylinder 1

💡 Pro Tip: Always swap parts to another cylinder to confirm the fault follows the part.

Repair Cost Estimate

Full Repair Estimate

$50–$300

DIY Possible?

YES

Severity

Critical

Frequently Asked Questions

What does OBD2 code P0301 mean?+

P0301 stands for Cylinder 1 Misfire Detected. The ECM has detected a misfire in cylinder 1. A misfire means the air/fuel mixture in that cylinder is not igniting properly or not igniting at all.

What causes code P0301?+

Faulty spark plug on cylinder 1; Bad ignition coil on cylinder 1; Clogged or failed fuel injector on cylinder 1; Low compression in cylinder 1

How do I fix code P0301?+

Swap spark plug from cylinder 1 to another and recheck; Swap ignition coil to another cylinder; Test injector with noid light; Perform compression test on cylinder 1

How much does it cost to fix P0301?+

Estimated repair cost for P0301 is $50–$300.

Is P0301 DIY-friendly?+

Yes — P0301 is generally DIY-friendly with basic tools.