P0272 means Cylinder 4 Contribution/Balance. The engine computer has measured that cylinder 4 is contributing more or less power than the others, usually by watching small changes in crankshaft speed. On diesels this most often points to the cylinder 4 injector or to low compression in that cylinder. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0272 means
Each fuel injector is a small solenoid that the engine computer switches on and off many times a second. The computer monitors every injector circuit for opens and shorts, and an injector circuit fault usually comes with a misfire on the same cylinder because that cylinder gets no fuel.
P0272 symptoms
- Rough idle or a miss
- Knocking or uneven running
- Smoke, loss of power or hard starting
Common causes of P0272
- Worn, sticking or leaking injector on cylinder 4
- Low compression in cylinder 4
- Air in the fuel or low fuel supply pressure
- Wiring fault to the injector
How to diagnose P0272
- Look at injector balance rates or contribution data on a capable scan tool
- Run a cylinder cutout test
- Check fuel supply pressure and filters
- Run a compression test on that cylinder
Can you drive with P0272?
Short term; a failing injector can damage the piston, so have it checked soon.
P0272 tips
Air in the fuel system can upset contribution readings on several cylinders at once; check supply pressure before focusing on one injector.
Will P0272 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0272 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0201 | Injector Circuit/Open – Cylinder 1 |
| P0087 | Fuel Rail/System Pressure Too Low |
| P0300 | Random/Multiple Cylinder Misfire Detected |
Guides that help
When it is more than a sensor
If an injector and its wiring test good but the cylinder still misfires, a compression test separates a fuel problem from a mechanical one; see engine replacement cost and our engines page if the engine is worn.
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