The P0286: Cylinder 9 Injector Circuit High refers to a problem in the electrical circuit controlling the fuel injector for cylinder 9, where the signal is too high. This issue may arise due to a shorted circuit, a faulty injector, or a malfunction in the injector driver within the ECM. This can result in poor engine performance, rough idling, or even misfires.
P0286 – Quick Overview
Meaning | P0286: Cylinder 9 Injector Circuit High |
Is it serious? | Yes, this code is serious as it can lead to misfires, poor engine performance, and increased emissions. It should be addressed promptly to avoid long-term damage. |
Possible causes | – Faulty cylinder 9 injector – Shorted circuit in the wiring – Faulty injector driver in the ECM |
How to diagnose? | – Check the wiring and connectors for the cylinder 9 injector – Test the cylinder 9 injector for proper resistance – Inspect and test the ECM for fault codes related to injector driver |
P0286 Meaning
The P0286: Cylinder 9 Injector Circuit High indicates that the signal sent to the fuel injector for cylinder 9 is higher than expected. This could be caused by a short in the wiring, a faulty injector, or an issue with the injector driver in the ECM. This condition could result in cylinder 9 receiving too much fuel or not functioning correctly, leading to poor engine performance or increased emissions.
Step-by-step diagnostic guide
Here is a step-by-step guide to troubleshoot and fix the P0286 error:
Action | Description | Tools Needed |
---|---|---|
Check for Other Codes | Use an OBD-II scanner to check for other related codes, which might give more insight into the issue. | OBD-II Scanner |
Inspect Cylinder 9 Injector | Visually check the cylinder 9 injector for any signs of damage, corrosion, or loose connections. | Flashlight, Safety Gloves |
Test the Injector | Use a multimeter to test the resistance of the cylinder 9 injector and compare it to manufacturer specifications. | Multimeter, Manufacturer’s Specifications |
Inspect Wiring and Connectors | Check the wiring and connectors for cylinder 9 for signs of wear, short circuits, or damage. | Flashlight, Multimeter |
Repair/Replace Wiring | If damaged or shorted wiring is found, repair or replace the faulty wiring and connectors. | Wire Strippers, Replacement Wires, Electrical Tape |
Inspect the ECM | Check the ECM for faults related to the injector driver. Reprogram or replace the ECM if necessary. | OBD-II Scanner, Multimeter |
Clear Code and Test Drive | After repairs, clear the P0286 code using an OBD-II scanner and take the vehicle for a test drive to confirm the issue is resolved. | OBD-II Scanner, Vehicle Owner’s Manual |
Recheck for Codes | Re-scan the vehicle after the test drive to ensure the P0286 code does not return. | OBD-II Scanner |
This guide will help you systematically diagnose and repair the P0286 code, ensuring proper functionality of cylinder 9 and restoring smooth engine operation.

Hi, I am Juraj “Yuri” Lukacko. I got frustrated by unhelpful and scammy mechanics, so I decided to learn everything about car diagnostics myself. I test dozens of new car diagnostic tools every month along with learning new strategies to fix and customize cars. About Juraj Lukacko (Yuri)