Cylinder 2 Misfire Detected on EFI Engine
The KOHLER-COMMAND-P0302 (Kohler Command EFI) diesel fault code means: Cylinder 2 Misfire Detected on EFI Engine. This is a serious severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $10-$30 DIY for spark plug and coil gap adjustment. Ignition coil replacement runs $40-$90 in parts DIY. Professional diagnosis and repair ranges from $150-$400 depending on root cause. Compression or injector issues can push pro repair to $500-$900 or more.
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Common Symptoms
- Engine runs rough or surges noticeably, especially at idle or under load
- Mower loses power when climbing hills or cutting thick grass
- You may smell unburned fuel from the exhaust
- Engine vibrates more than usual at operating speed
- EFI fault light or dash warning indicator comes on while mowing
- RPM drops and engine struggles to recover when blades engage
- Engine may backfire or pop intermittently through the exhaust
Probable Causes (Ranked by Likelihood)
- Fouled or failed spark plug on cylinder 2 Very Likely
- Weak or failed ignition coil on cylinder 2 side Very Likely
- Clogged or stuck-open fuel injector on cylinder 2 Likely
- Low compression on cylinder 2 due to worn rings, valve, or head gasket failure Likely
- Damaged or corroded spark plug wire or boot on cylinder 2 Possible
- Air leak at the intake manifold or gasket on the cylinder 2 side Possible
- ECM fault or wiring harness issue causing incorrect injector or coil signal to cylinder 2 Less Likely
Step-by-Step Diagnostic Procedure
Start by pulling the spark plug from cylinder 2. On most Kohler Command V-twins, cylinder 2 is on the right side of the engine when viewed from the flywheel end. Inspect the plug for fouling, cracking, or a worn electrode. The gap should be 0.030 inches (0.76 mm). Replace if in doubt. Plugs are cheap insurance.
Swap the spark plug from cylinder 1 into cylinder 2 and run the engine. If the misfire moves to cylinder 1, the plug was the problem. If it stays on cylinder 2, move on to the coil.
Inspect the ignition coil on the cylinder 2 side. Check the air gap between the coil and flywheel magnets. Kohler specs this at 0.010 inches (0.25 mm). A feeler gauge works fine. A coil that is too far away will produce a weak spark under load.
With the engine off, unplug the ignition coil connector on cylinder 2 and check for corrosion or pushed-back terminals. Wiggle the connector firmly seated. A loose coil connection causes intermittent misfire that is easy to miss.
Measure coil primary resistance across the two primary terminals with a multimeter set to ohms. Kohler Command EFI coils typically read 0.4 to 1.5 ohms on the primary winding. Out of range means replace the coil.
If the coil and plug check out, connect a fuel pressure gauge to the Schrader valve on the fuel rail. Kohler EFI systems should hold 36 to 40 PSI at key-on and maintain pressure at idle. A leaking injector on cylinder 2 will show up as a pressure drop at idle or a rich-smelling exhaust on that side. This step requires a fuel pressure gauge, which most dealer techs have.
Do a compression test on cylinder 2. A healthy Kohler Command cylinder should read 150 PSI or above, and both cylinders should be within 10 percent of each other. Low compression on cylinder 2 points to rings, a valve not seating, or a blown head gasket. This is an advanced repair requiring teardown.
If all the above check out normal, retrieve stored codes using the Kohler PCM diagnostic tool and check for additional codes that could indicate a wiring or ECM problem. An ECM fault affecting injector timing or coil trigger on one cylinder is rare but does happen.
Frequently Asked Questions
What does Kohler Command code P0302 mean?
It means the ECM detected that cylinder 2 is not firing consistently. The engine is running on one cylinder most of the time or firing weakly on cylinder 2. Most of the time this is a spark plug, ignition coil, or injector issue on that specific cylinder.
Can I keep mowing with a P0302 code active?
You can run the mower for a short time to finish a job, but you should not ignore it. Running with a misfire puts extra heat and load on cylinder 1, can wash down cylinder 2 walls with raw fuel, and may damage the catalytic converter or oxygen sensor if your engine has one. Get it diagnosed within a day or two.
How much does it cost to fix a P0302 on a Kohler EFI mower engine?
If it is just a spark plug, you are looking at $10 to $20 in parts and 15 minutes of your time. An ignition coil is $40 to $90 in parts DIY. If you take it to a dealer, expect $150 to $400 for diagnosis and a plug or coil swap. A low-compression repair involving valves or rings can run $500 to $900 or more at a shop.
Why is cylinder 2 misfiring but cylinder 1 is fine?
Kohler Command V-twins fire each cylinder independently with separate coils, plugs, and injectors on EFI models. Problems that affect one cylinder and not the other are almost always hardware on that side, like a bad plug, weak coil, or clogged injector. It is rare for both cylinders to fail at the same time from the same part.