OBD-II Code · Powertrain
P0302
Cylinder 2 Misfire Detected
Severity
high
Left alone, this one tends to take other parts with it.
Can you drive it
Depends on the light
Flashing: stop as soon as it is safe to — raw fuel is reaching the catalytic converter. Steady, and it only feels rough: a short drive to a shop is usually fine. Either way, stop if it shakes hard, loses power, overheats or makes a new noise.
Indicative cost (USD)
$30–$400
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
Swap coil from a known-good cylinder first
Cylinder 2 is misfiring. Same root causes as P0301 but on cylinder 2.
How a shop works this
The ECU has already told you which cylinder. That makes the fastest honest test a swap: move one part to another cylinder and see whether the fault moves with it. It identifies the fault instead of guessing at it, and it costs nothing.
Photograph the coils before you touch anything, and note which is which.
Cylinder numbering is not the same across manufacturers, and V6 and V8 bank layouts differ by maker — look up the firing order and bank layout for your engine before you move parts, or you can spend an hour swapping coils on the wrong bank.
Move the cylinder 2 ignition coil to a cylinder that is not misfiring, put that cylinder's coil on 2, clear the code, and run it until the misfire returns.
On a modern coil-on-plug engine the coil is the most common single answer to a cylinder-specific misfire, which is why it is the first thing to move — not because it is the cheapest part. A misfire that is there even at idle is the classic dead-coil pattern.
- The misfire follows the coil to its new cylinderThe coil is the fault. Replace it. If the engine has real mileage on it, the other coils are on the same clock.
- The misfire stays on cylinder 2The coil is fine. Look at the coil connector and the harness around it next — chafed and rodent-damaged connections at that plug are a common second answer — then pull the plug.
Read the plug you pulled, and check the boot for carbon tracking.
Black and sooty means it has been running rich. White or blistered means lean or too hot. Oil-wet points at valve seals or rings. Fuel-wet points at an injector holding open. A carbon-tracked boot arcs to the head and imitates a dead coil for the price of a new boot. On an older engine with a distributor, the cap, rotor and plug wires belong in this step too.
If spark is accounted for, go to fuelling, then to compression.
An injector balance or flow test comes first because it is quicker. Compression test second: a cylinder more than about 15% below its neighbours is mechanical, and no ignition part will fix it. A vacuum leak on this one runner sits alongside these — a leak big enough to affect every cylinder would be setting P0300 instead.
A flashing check-engine light means the misfire is putting raw fuel into the catalytic converter, which can destroy it quickly. Stop driving as soon as it is safe to. A steady light with a mild misfire is less urgent, but stop anyway if it shakes hard, loses power, overheats, or makes a noise it was not making before.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Rough idle
- Engine hesitation
- Check engine light
- Fuel smell at cylinder 2 exhaust
Likely causes
- Failed ignition coil (cylinder 2)Most common
- Damaged coil connector or harness at cylinder 2
- Worn spark plug or carbon-tracked boot (cylinder 2)
- Clogged or leaking fuel injector (cylinder 2)
- Low compression on cylinder 2
- Vacuum leak at the cylinder 2 intake runner
Read the full diagnostic procedureP0302 means cylinder 2 specifically is misfiring per the crankshaft-deceleration monitor.
P0302 means cylinder 2 specifically is misfiring per the crankshaft-deceleration monitor.
The shop-floor diagnostic flow is identical to any cylinder-specific misfire
- pull plug and coil from cylinder 2, read the plug (carbon-fouled, oil-wet, fuel-wet, or normal-but-dead), swap the coil with an adjacent cylinder, clear the code, and see if the misfire follows the coil.
- If swapping doesn't fix it, swap plugs.
- If swapping plugs doesn't fix it, run a compression test on cylinder 2 — anything below 85% of the highest-reading cylinder is a mechanical problem (rings, valve, head gasket between 2 and an adjacent cylinder).
- If compression is good, the next test is an injector balance/flow test: a clogged injector flows less fuel and creates a lean misfire that won't show up on a coil/plug swap.
- A 10-15 minute coil swap catches roughly 60% of P030X codes on vehicles with over 80,000 miles.
Vehicle-specific patterns2007-2012 Nissan Altima/Sentra with the QR25DE 2.5L frequently throws P0302 from a known timing-chain stretch issue that retards cam timing on the re…
- 2007-2012Nissan Altima/Sentra with the QR25DE 2.5L frequently throws P0302 from a known timing-chain stretch issue that retards cam timing on the rear cylinders specifically — there's a Nissan TSB and extended warranty in some markets, check VIN coverage before quoting a coil pack.
- 2004-2008Chrysler/Dodge 3.5L and 4.0L V6 (Pacifica, 300, Charger) commonly throws P0302 from a cracked rear exhaust manifold causing post-cat O2 confusion and a lean misfire on cylinder 2.
- 2010-2015Hyundai Sonata/Tucson with the Theta II 2.4L GDI frequently throws P0302 from carbon buildup on the direct-injection intake valves (no port-injection wash); walnut blast resolves it.
Estimated repair$40 (single coil DIY) to $2,500+ (timing chain job on the Nissan QR25).
Look up another code
P0302 — frequently asked
What does a P0302 code mean?
Cylinder 2 is misfiring. Same root causes as P0301 but on cylinder 2.
What causes a P0302 code?
Common causes: Failed ignition coil (cylinder 2); Damaged coil connector or harness at cylinder 2; Worn spark plug or carbon-tracked boot (cylinder 2); Clogged or leaking fuel injector (cylinder 2); Low compression on cylinder 2; Vacuum leak at the cylinder 2 intake runner.
What are the symptoms of a P0302 code?
Typical symptoms: Rough idle; Engine hesitation; Check engine light; Fuel smell at cylinder 2 exhaust.
Is it safe to drive with a P0302 code?
Depends on the light. Flashing: stop as soon as it is safe to — raw fuel is reaching the catalytic converter. Steady, and it only feels rough: a short drive to a shop is usually fine. Either way, stop if it shakes hard, loses power, overheats or makes a new noise. Estimated repair: $30-$400 — swap coil from a known-good cylinder first.
How do I diagnose a P0302 code?
The ECU has already told you which cylinder. That makes the fastest honest test a swap: move one part to another cylinder and see whether the fault moves with it. It identifies the fault instead of guessing at it, and it costs nothing. 1. Photograph the coils before you touch anything, and note which is which. 2. Move the cylinder 2 ignition coil to a cylinder that is not misfiring, put that cylinder's coil on 2, clear the code, and run it until the misfire returns. 3. Read the plug you pulled, and check the boot for carbon tracking. 4. If spark is accounted for, go to fuelling, then to compression.
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