P02F0: Cylinder 3 Injector Circuit Range/Performance
What to do
Say whether the fault appears only once the engine is warm, or after a longer drive. That is genuinely important — a fault that only shows up hot is almost always a wiring or connector problem rather than the injector, because resistance rises with temperature.
A test done on a cold engine can easily find nothing, so it is worth mentioning the pattern explicitly so the check is done under the right conditions.
Ask whether the rocker cover gasket is leaking. On many engines oil from that gasket runs into the injector connectors and degrades them, and replacing an injector without fixing the leak means it happens again.
Do not delay the repair, since unburnt fuel from a misfiring cylinder can damage the catalytic converter or particulate filter.
What this code means
The electrical behaviour of cylinder 3's injector circuit is wrong, without being open or short.
The module drives the injector and measures the resulting current waveform; cylinder 3's no longer has the shape a healthy injector produces.
Temperature is the variable worth attending to on this code, because it is what makes these faults intermittent. Resistance rises with temperature, so a marginal connection that measures acceptably on a cold engine in a workshop can fall outside tolerance once the engine bay reaches full heat.
A driver reporting that the fault appears after twenty minutes of driving, or on a long run rather than a short one, is describing a thermal fault — and that is a connection or a harness far more often than an injector.
So a measurement taken cold that finds nothing has not cleared the wiring. The test that matters is taken hot, or with the connector warmed deliberately while the waveform is watched.
On an inline engine, cylinder 3 sits in the hottest part of the block, which makes it the one most likely to show a thermal problem first. That is a reason to suspect heat rather than to assume this injector is uniquely worn.
Check for oil in the connector as well. A leaking rocker cover gasket delivers oil directly into injector connectors on many engines, and it degrades the contact steadily.
Likely causes
Start here
- Corroded or loose connector · easy
- Oil in the sensor connector · easy
- Failed fuel injector · specialist
Less common
- Heat damage to wiring insulation · moderate
- Intermittent open in sensor wiring · moderate
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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- The car — make, model, year and engine. The same fault behaves differently on each.
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