P02F6: Cylinder 9 Injector Circuit Range/Performance

P02F6 reports an electrically implausible response of the cylinder 9 injector – not an open or short circuit (those are P0209, P0285 and P0286), but a current or voltage pattern outside the expected range. Cylinder 9 exists only on engines with ten or more cylinders; GM and Ford documents stop at cylinder 8, so the description follows CARB and the documented checks for cylinders 1–8 (current fall time, voltage feedback, regulator at its limit). The injector may be shut off, causing misfire.

Medium severity. Can I keep driving?Drive as little as possible and go to a repair shop. If you smell fuel or the engine is shaking badly, do not keep driving.

Cylinder 9 is numbered according to the manufacturer: check your engine's manual before working on it.

Symptoms

Check engine light on
Rough running, misfire on cylinder 9
Loss of power, smoke (diesel)

Most likely causes

Injector electrically aged (piezo capacitance, coil resistance)
Contact resistance in the injector 9 connector or wiring
Injector mechanically sticking (valve lift)
Injector driver stage in the engine module

What to check, in order

Start with the simplest. You can tick off each step.

Check the connector and wiring of the injector indicated
Compare the reading with other engine data while varying the engine speed.
Measure the resistance and compare it with the manufacturer's specification
Check the control signal with an oscilloscope; on direct injection or diesel engines, leave this to a repair shop because of the high voltages
On diesels, check the per-cylinder injection corrections

Good to know

Repair difficulty: hard
It can trigger limp mode.
It affects emissions.

What each character of P02F6 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
2: Fuel injection
F6: Specific fault in that system

Frequently asked questions

Can I keep driving with code P02F6?

Drive as little as possible and go to a repair shop. If you smell fuel or the engine is shaking badly, do not keep driving.

What causes code P02F6?

The most common causes are: injector electrically aged (piezo capacitance, coil resistance); contact resistance in the injector 9 connector or wiring; injector mechanically sticking (valve lift).

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.