P0302 means the engine computer has detected a misfire on cylinder 2, and the code does not by itself name the part that failed. Manufacturer service bulletins list causes that range from spark plugs to valve train wear.
The right fix depends on the make, the engine and the vehicle’s history. Start with the stored codes and the easiest checks before you replace any part.
P0302 Code: Cylinder 2 Misfire Explained
P0302 is the No. 2 cylinder misfire code. A GM service bulletin defines it as “Cylinder 2 Misfire Detected,” and a Honda bulletin uses the same wording, “No. 2 cylinder misfire detected.”
The code sits in a family of related codes. The Honda bulletin lists P0300 for a random misfire, P0301 for cylinder 1, P0303 for cylinder 3 and P0304 for cylinder 4. The GM bulletin lists the same family up to P0308 on V8 engines.
A misfire may or may not be felt by the driver. The GM bulletin notes that it can happen at all engine speeds or only at a specific speed, such as idle or high RPM, so the code can show up before the symptom is obvious.
What Causes a P0302 Code
The causes depend on the engine. A GM service bulletin for V8 engines from 2002 to 2018 lists the following possible sources of a P0302 and the related misfire codes, GM service bulletin 19-NA-219:
- Worn camshaft lobe or lifter roller, which can also create a chirp, squeak or tick at camshaft speed.
- A sticking valve or valve leakage, which can cause a consistent misfire at idle or low RPM.
- A broken valve spring.
- A collapsed Active Fuel Management lifter.
A Honda bulletin for 2017 to 2018 CR-V models takes a different angle. It says that under certain driving patterns and environmental factors, misfire codes including P0302 may be set, and that fouled spark plugs are part of the repair path.
Because the bulletins are model specific, a cause that fits one engine may not fit yours. Use the list as a set of candidates, not a diagnosis.
Two details matter when you read a service bulletin. First, the year, make and engine must match the bulletin’s scope before any repair applies. Second, the bulletin’s wording tells you whether it is written for technicians or for any owner. Read that scope line first, because a repair written for one engine family may not apply to yours.
A misfire on one cylinder often shows up as a change in how the engine runs rather than as a warning you can see. Note when the roughness happens, such as on a cold start, at idle or at highway speed, since those details help a technician match the conditions in the bulletin.
How to Fix P0302: Check in Order
Fix a P0302 by working through the checks in order, starting with the cheapest and easiest. The GM bulletin says to review the listed causes and start with the easiest ones when standard diagnosis does not isolate the problem.
- Read all stored codes and write them down before you clear anything, since the Honda bulletin says to note the stored DTCs on the repair order.
- Inspect the spark plugs. If they are fouled, replace them, because the Honda bulletin lists spark plug replacement as the first repair step.
- Check for stored misfire codes again. If the misfire codes do not return, the repair is complete, according to the bulletin.
- If the codes return and the plugs were clean, look at the valve train, such as camshaft lobes, lifters and valve springs, as the GM bulletin describes.
- If the cause is still not clear, take the car to a technician with the right tools, because the Honda bulletin is written for skilled technicians.
The GM bulletin also warns that the cause may not be isolated after standard diagnosis. In that case, the next step is a more detailed check of the engine, not a guess at a new part.
Keep a simple log while you work through the list. Note the date, the mileage, the stored codes and what you replaced. A log makes it easier to see whether a change fixed the misfire or only cleared the code for a while.
A basic scanner can show the stored code, but the bulletins expect a technician to run the deeper checks. Treat the scanner as the first tool in the process, not the last one.
P0302 Code Cost to Fix: Labor Time Matters
Labor time is one of the clearest cost drivers, and the Honda bulletin gives flat-rate times for the repair tiers it describes. Parts and shop rates are not included in those times, so use them to compare the scope of each repair. Treat the table as a comparison tool rather than a price list.
| Repair in the Honda bulletin | Flat-rate labor time |
|---|---|
| Replace spark plugs | 0.5 hour |
| Remove valve cover and inspect camshafts, no replacement | 0.7 hour |
| Replace camshafts and rocker arm assembly | 5.1 hours |
The gap between a spark plug job and a camshaft job is large, which is why the cause matters before any work starts. A P0302 that clears after plugs costs far less in labor than one that needs valve train parts.
Shop quotes often combine labor and parts into one figure. Ask for the labor time and the parts list separately, so you can compare the quote with the bulletin’s flat-rate times and see where the money goes.
Can You Drive With a P0302 Code?
Neither bulletin sets a mileage limit for a P0302, so the sources do not say how far you can safely drive with the code. The practical default is to check the code and the engine behavior soon rather than waiting.
Your owner’s manual explains what a flashing malfunction light means for your vehicle. Treat a flashing light as a reason to act sooner, not later, and follow the manual’s advice.
Watch for a rough idle, hesitation or a light that changes behavior. Those signs can accompany an active misfire, and the stored code alone does not tell you how severe it is.
P0302 Compared With Other Misfire Codes
P0302 names one cylinder, which narrows the search. Compare it with the codes in the same family before you assume the problem is the same on every cylinder. This list also helps when a scanner shows more than one misfire code at once. On engines with six or more cylinders the same pattern continues, and the P0306 cylinder 6 misfire code guide covers the sixth cylinder.
- P0300: a random misfire, not tied to one cylinder.
- P0301: a misfire on cylinder 1.
- P0302: a misfire on cylinder 2.
- P0303 and P0304: misfires on cylinders 3 and 4.
The Honda bulletin lists P0300 through P0304 together as codes that the same driving and environmental conditions can set, so several codes at once may point to a shared cause. Confirm that with a technician before buying parts.
The engine computer reports the cylinder, not the reason the cylinder misfired. The bulletins show that the cause can sit in the spark plugs, the valve train or the conditions the car has been driven in. Plan the checks around those three areas, and do not treat the cylinder number as the part number.
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Frequently Asked Questions
Is a P0302 code serious?
A P0302 means a misfire was detected on cylinder 2. Both bulletins treat it as a diagnosis item for a skilled technician, so do not ignore it. Check the code and the engine behavior soon, and do not assume it is harmless because the car still runs.
Can a spark plug cause a P0302 code?
Yes, according to the Honda bulletin, which says fouled spark plugs should be replaced and lists that as the first repair step. Inspect the plugs before you move to more expensive work, and note whether the code returns after the replacement.
Will the P0302 code come back?
It can. The Honda bulletin says misfire codes may return after the spark plug repair. If they do, the next step is to inspect the plugs again and check the stored codes before deciding the bulletin does not apply.
Does clearing the code fix the problem?
No. Clearing the code does not repair the misfire, and the GM bulletin notes that the cause may not be isolated after standard diagnosis. Record the stored codes before you clear them, so the next technician has the same starting point.
Does the P0302 code cost a lot to fix?
The cost depends on the cause. The Honda bulletin’s labor times run from 0.5 hour for spark plugs to 5.1 hours for camshaft and rocker arm replacement, and parts and shop rates are not included in those times.
Write down the stored codes, check the spark plugs and confirm the cause before you replace parts. A P0302 fix that starts with the easy checks saves time, and it keeps the record clear for any technician who works on the car next.
