P0302
Cylinder 2 Misfire DetectedP0302 is a generic OBD-II powertrain diagnostic trouble code: Cylinder 2 Misfire Detected. It is logged by the engine control unit when the misfire monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0302 means
DTC P0302 is an SAE-standard powertrain code meaning Cylinder 2 Misfire Detected. A misfire occurs when combustion in cylinder 2 fails to fire correctly — or at all — during a power stroke. The Powertrain Control Module (PCM) detects this by continuously monitoring crankshaft rotational velocity via the crankshaft and camshaft position sensors; a misfiring cylinder causes a brief, measurable deceleration of the crank, and the PCM uses this signature to identify both the presence and location of the misfire.
P0302 is cylinder-specific: it tells you where the misfire is happening but not why. The root cause can lie in the ignition system (spark plug, coil, wiring), fuel delivery (injector, fuel pressure), or engine mechanical condition (compression loss, sticking valves, worn rings). A continuously illuminated MIL indicates an intermittent or low-rate misfire; a flashing MIL indicates a high-rate misfire severe enough to damage the catalytic converter and requires immediate attention.
Left unaddressed, a persistent cylinder 2 misfire can introduce raw fuel into the exhaust stream, overheat and destroy the catalytic converter, cause rough idle, reduce fuel economy, and — in severe cases — lead to engine damage from hydrolocking or oil dilution. The underlying cause should be diagnosed and repaired promptly.
Common causes
Most-frequently reported root causes when P0302 is logged.
-
1
Worn, fouled, or incorrectly gapped spark plug on cylinder 2
-
2
Failed or weak ignition coil on cylinder 2
-
3
Damaged ignition coil wiring, connector, or short to ground on cylinder 2
-
4
Clogged, leaking, or failed fuel injector on cylinder 2
-
5
Low fuel pressure or failing fuel pump affecting injector performance
-
6
Loss of compression on cylinder 2 (worn piston rings, damaged valves, blown head gasket)
-
7
Vacuum leak or intake manifold gasket leak affecting cylinder 2 air-fuel mixture
-
8
Faulty crankshaft or camshaft position sensor causing incorrect misfire attribution
Symptoms drivers notice
How to diagnose P0302
A typical diagnostic flow when this code is present.
-
1
Retrieve freeze-frame data with a scan tool and note RPM, load, and coolant temperature at the time of the fault to guide testing conditions
-
2
Inspect the cylinder 2 spark plug — check for fouling, cracks, or incorrect gap; replace if worn
-
3
Swap the cylinder 2 ignition coil with a known-good cylinder's coil and clear codes; if the misfire follows the coil, replace it
-
4
With the coil swapped back, use a noid light or injector pulse tester to verify cylinder 2 fuel injector is firing; check resistance and replace if out of spec
-
5
Perform a cylinder compression test on all cylinders; low compression on cylinder 2 (relative to others) points to mechanical wear, valve sealing, or a head gasket fault
-
6
Check fuel pressure at idle and under load; pressure below spec can cause lean misfires across multiple cylinders
-
7
Inspect crankshaft and camshaft position sensor wiring for chafing, corrosion, or poor pin contact at the PCM connector
Related powertrain codes
Frequently asked questions
Can I keep driving with a P0302 code?
Short distances at low load may be unavoidable, but continued driving is not recommended. A flashing MIL means the misfire is severe enough to overheat and permanently damage the catalytic converter within minutes of driving. Even with a steady MIL, raw fuel entering the exhaust and the mechanical stress of repeated misfires can cause escalating damage. Address the fault as soon as possible.
Is P0302 always caused by the spark plug or coil?
Ignition components are the most common cause and should be checked first because they are cheap and easy to swap, but they are not the only cause. Fuel injector failure, low fuel pressure, and mechanical issues such as low compression or a leaking head gasket can all trigger P0302. A systematic swap-and-test approach rules out ignition before moving to the more involved fuel and mechanical checks.
Why does the misfire only occur at certain RPMs or under load?
Intermittent misfires that appear only at high RPM or under heavy load often point to a marginal ignition coil that cannot sustain the higher voltage demand, a partially clogged injector that starves the cylinder at high fuel-demand conditions, or a vacuum leak that worsens the lean condition under load. Capturing live data with a scan tool while replicating the fault condition helps isolate the cause.
Will clearing the code fix the problem?
No. Clearing the code only erases the stored fault and resets the MIL; if the underlying cause is not repaired, the PCM will detect the misfire again and re-set P0302, typically within one or two drive cycles. Clearing codes before diagnosis can also erase useful freeze-frame data that helps pinpoint the fault conditions.
Disabling P0302 in software
RaceTune can permanently disable P0302 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
Got P0302 in your scan?
Upload your ECU file — we'll identify the exact software version and confirm whether a disable is available for your car.
Upload your file