P0284 — Cylinder 8 Injector Circuit High
Drive with caution — fix soon.
What P0284 means
This code means the engine computer detected high voltage or an open in the electrical circuit for the cylinder 8 fuel injector. It usually points to a broken or disconnected wire, a corroded connector, or a failing injector on that cylinder. It's an electrical circuit fault that's typically fixed by repairing wiring or replacing the injector, not major engine work.
Common symptoms
- Check engine light is on
- Rough idle or engine shaking
- Hesitation or reduced power when accelerating
- Misfire on cylinder 8
- Possible hard starting or stalling
Common causes
- Open or broken wire in the cylinder 8 injector circuit
- Corroded or disconnected injector connector
- Failing fuel injector on cylinder 8
- High resistance in the injector wiring
- Fault in the engine computer's injector driver
Typical repair cost
$120 – $600
Varies by vehicle and root cause.
Frequently asked questions
Can I keep driving with a P0284 code?
Usually yes for short trips, but it's not ideal. The cylinder 8 injector may not be working right, causing rough running and possible converter damage over time. Have it checked soon.
How much does it cost to fix a P0284 code?
Fixing a wire or connector can start around $120, while replacing the injector usually runs $300 to $600 depending on your vehicle. Diagnosis confirms whether it's wiring or the injector itself.
Is a P0284 code serious?
It's moderate. The engine often still runs, but a cylinder that isn't fueling properly hurts performance and can damage the catalytic converter if ignored. Fix it promptly to be safe.
What's the difference between P0284 high and P0283 low?
Both involve the cylinder 8 injector circuit. P0283 means the computer saw low voltage, often a short, while P0284 high usually means an open circuit or broken connection. The diagnosis differs slightly, but both point to wiring or the injector.