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P0286 OBD-II Trouble Code: Cylinder 9 Injector Circuit High

check engine light

P0286 code definition

When the P0286 code gets stored, it’s because the vehicle’s ECM has received a voltage reading from the fuel injector circuit that isn’t within the parameters designated by the manufacturer. The reading could have also come from the fuel injector in cylinder nine.

What the P0286 code means

This code means that voltage variations that exceeded 10% of the amount outlined by the manufacturer were registered. It usually indicates that engine cylinder nine isn’t operating or, at best, is doing so poorly. Under normal conditions, fuel injectors would be turned on and off by the ECM.

What causes the P0286 code?

The P0286 code is usually the fault of wildlife. Squirrels and other creatures will be attracted by the warmth of your engine after you’ve parked and actually climb inside to rest on top of it. Once they do, it’s often only a matter of time before they go on to chew through some of your vehicle’s wiring.

Other causes could be:

  • Loose or corroded connector faces or wiring
  • Clogged fuel injectors
  • Faulty fuel injectors
  • Faulty fuel injector driver located in the PCM

What are the symptoms of the P0286 code?

If a P0286 code has been stored, you should notice the Check Engine light come on. However, a far more obvious indicator would be your engine misfiring. That’s not at all uncommon. It’s also not rare for the engine to begin running rough, resulting in subpar fuel economy. Even when you’re sitting idle, you may feel vibrations coming from the transmission or even feel it vibrating. Trying to accelerate will most likely be choppy too.

How does a mechanic diagnose the P0286 code?

Your mechanic will use a code reader to begin their assessment. A noid lamp and your vehicle’s service manual will come in handy too for figuring out what the appropriate voltage is supposed to be. They will also inspect electrical components, connectors and wires. Fuses and the fuse panel will be inspected as well. A continuity and resistance test may be necessary as well.

Common mistakes when diagnosing the P0286 code

Open or shorted circuits often don’t get addressed which makes an accurate diagnosis and correct repairs impossible. Usually, if a mechanic misses that the fuel injection system has open or shorted circuits, they’ll go on to assume that the PCM isn’t working correctly and replace it – an expensive measure if not necessary.

Faulty fuel injectors can cause the same type of misdiagnosis and unfortunately response.

How serious is the P0286 code?

A P0286 code is definitely something you’ll want a qualified mechanic to inspect right away. A bad fuel injector is bound to cause further damage to other parts of your car, which could cost you a lot of money in repairs and, in the meantime, keep your vehicle from operating. For example, a malfunctioning fuel injector will affect the spark plug, cause detonation, affect the catalytic converter and oxygen sensor, and much more.

What repairs can fix the P0286 code?

Your mechanic will have to do one of the following to fix the P0286 code:

  • Replace the damaged wiring or other electrical components
  • Replace damaged fuel injectors
  • Cleaning out clogged fuel injectors
  • Fix blown fuses
  • In rare cases, replacing a faulty PCM

Additional comments for consideration regarding the P0286 code

As we mentioned above, PCM failure probably isn’t the cause of P0286. It’s possible, but rare. If both a ground pulse and constant power supply are present, determine if the injector or injectors in question are activating by using a listening device.

Need help with a P0286 code?

The team at YourMechanic is here to help if your vehicle’s performance is currently being hindered because of an issue related to P0286. Give us a call at 1-800-701-6230 to speak with a service advisor or simply fill out our online form and let us know when you’d like your appointment to be. We’ll provide you with a quote regarding repairs and then dispatch a certified mobile mechanic to your place of work or home where they’ll fix your vehicle on the spot.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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