P0286 explained: High-voltage fault on the injector control means the PCM cannot pull the injector low to fire it. The injector coil may be open, or the high-side wire shorted to power. Cylinder 8 will be dead - misfires follow.
🎯 Top Causes & Probability
50%
#1 - Most Likely
Open Injector Coil
The injector winding has burned open. Common after 120k miles on port-injection V8s.
🔨 Part
$80-$450
👨🔧 Labor
$100-$350
⚡ DIY
Medium
30%
#2 - Check First
Broken Wire or Bad Connector
A wire to the injector is open. Often at the connector itself - reseat or repin before buying parts.
🔨 Part
$15-$60
👨🔧 Labor
$80-$220
⚡ DIY
Medium
15%
#3 - Less Common
PCM Output Driver Failed
Rare. The driver for cylinder 8 has failed in the high state. Verify only after injector and wiring confirmed good.
🔨 Part
$400-$1100
👨🔧 Labor
$120-$240
⚡ DIY
Hard
🚗 Most Affected Vehicles
🔧 Step-by-Step Diagnosis
- Pull DTC freeze-frame and note RPM, load, and short-term fuel trim when the code set.
- Inspect the cylinder 8 injector connector for melted insulation, corrosion, or backed-out pins.
- Unplug and measure injector resistance. Open reading (OL) confirms a dead injector coil.
- Back-probe with key on engine off. The high-side pin should show +12V from the injector relay. No voltage = blown fuse or relay.
- Swap the injector with cylinder 7 to confirm. If the code moves to cylinder 7, the injector is bad.
- After repair, verify all cylinders contribute equally with a relative compression or balance test.
❓ Frequently Asked Questions
Can I just clean the injector?
Ultrasonic cleaning helps when the injector is clogged but firing. If the coil is electrically open, cleaning does nothing. Test first.
Is the injector the same on all 8 cylinders?
Yes on almost every modern V8. You can swap them between cylinders to confirm a fault.
Why only cylinder 8 and not the others?
Heat exposure and wire routing differ by cylinder. Rear cylinders on V8s see more heat and shorter spark plug life - injectors follow the same pattern.
Will P0286 damage the catalytic converter?
Yes if ignored. Raw fuel from the dead cylinder dumps into the cat. A cat replacement is $400-$2500 - much more than an injector.
Should I run an injector cleaner first?
A bottle of Techron in a tank of gas is cheap and worth trying. If P0286 returns within a tank, the injector is electrically failed and needs replacement.