Cylinder 1 Misfire Detected

Severity

High

Can I keep driving?

Avoid extended driving; visit a service soon.

First step

A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training. 1. Inspect cylinder 1's spark plug, fouling, wear, or damage often visible 2. Swap the cylinder 1 coil with a coil from a healthy cylinder; if the misfire moves to the new cylinder, the coil is the fault 3. Swap the injector similarly to test 4. Compression test cylinder 1 against the others 5. Cylinder leak-down test if compression is low

PPowertrain
0Generic code
3Ignition / Misfire
01Sequence number

What does it mean?

A misfire is just what it sounds like; a cylinder that is not firing as it should. The P0301 code is caused by a misfire on the number one cylinder. The Misfire monitor diagnostic is based on variation in crankshaft velocity. The PCM determines this information using the crankshaft position sensor and camshaft position sensor. A misfiring cylinder slows down momentarily, so by monitoring the cam and crank sensor signals, the PCM can calculate when a misfire occurs. A P0301 code tells you only that a misfire has been detected, not WHY the cylinder is misfiring. That’s why with this code, a thorough diagnosis is mandatory.

Symptoms

Likely causes

How to fix it

Codes From the Same System

All Fault Codes

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This information follows the generic OBD-II definition and does not replace a vehicle-specific diagnosis. The severity rating is rule-based; an authorised diagnostic reading is required for a definitive answer.