Technical Description of OBD-II Trouble Code
The fuel injector circuit for Cylinder #9 is experiencing high voltage
What does that mean?
This diagnostic trouble code (DTC) is a generic powertrain code that applies to vehicles equipped with OBD-II. While it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
Trouble code P0286 is a generic code that is common to all manufacturers. It indicates that the fuel injector servicing the number nine cylinder is drawing an above average amount of current.
The engine cylinder #9 injector is either operating poorly or not at all due to a problem within the circuit. It is important to note that while this code is common to all vehicles, the prognosis may vary between manufacturers.
For example, some manufacturers may have experienced issues with a batch of fuel injectors or other defective components specific to their vehicles.
It is crucial to address this type of problem as soon as possible to prevent damage to other internal components. A faulty fuel injector can affect the spark plug, cause detonation, impact the oxygen sensor and catalytic converter, and affect several other components as well.
Go online and access the technical service bulletins (TSBs) for your specific vehicle. Look for any TSBs related to P0286 and follow the suggested repair procedure.
Here is a cross-section diagram of a typical automotive fuel injector (provided by WikipedianProlific):
Symptoms
The symptoms associated with a P0286 code may include:
Causes
Potential causes for this DTC include:
Diagnosis and Repair Procedure
In my experience, the problem is typically a corroded or loose fuel injector connector, or a faulty fuel injector.
A loose connector causes excessive resistance, which increases the voltage required for operation. The wiring harness to the powertrain control module (PCM) is not easily accessible and is rarely faulty if left undisturbed.
On the other hand, the fuel injector is susceptible to various issues. The main problem is fuel with anhydrous ethanol content. This fuel additive reduces fuel consumption but produces water vapor that has a negative effect on the fuel injectors. Fuel injectors rely on fuel for lubrication, and water vapor reduces the friction-reducing properties of gasoline, leading to premature wear in the injector.
Small engine manufacturers do not recommend the use of ethanol-based fuels as they significantly reduce the service life of a small engine.
