P0284
Fix within a few daysCylinder 8 Fuel Injector Circuit Low Voltage
Code P0284 means Cylinder 8's fuel injector circuit has a low voltage condition. Common causes: Faulty injector (70%), wiring issues (25%). Drivability: No, stop driving if flashing CEL. Repair cost: $100-$300 DIY, $250-$700 professional.
Can I Drive With P0284?
No, stop driving
Immediate repair needed. If the Check Engine Light is flashing, stop driving immediately to prevent severe damage to your catalytic converter.
Stop driving immediately if: Flashing Check Engine Light, strong smell of raw fuel, significant power loss, loud knocking or banging from the engine.
Symptoms of P0284
- 1Engine misfire or rough idle
- 2Reduced engine power
- 3Poor fuel economy
- 4Check Engine Light is on (may be flashing if misfire is severe)
- 5Engine may run rough or shake
Common Causes of P0284
Parts most likely causing this code, ranked by probability
The fuel injector itself has failed internally, causing a low voltage condition in its electrical circuit.
70% of P0284 cases are fixed by replacing this part
A damaged wire, loose connection, or corrosion in the wiring harness leading to the Cylinder 8 fuel injector causes the low voltage.
25% of P0284 cases are fixed by repairing this part
The PCM's internal driver circuit for the Cylinder 8 injector has failed, preventing proper voltage control.
5% of P0284 cases are fixed by replacing this part
Check These First (Before Buying Parts)
- Visually inspect the wiring harness and connector for the Cylinder 8 fuel injector for any signs of damage, corrosion, or loose connections.
- Listen for the distinct clicking sound of the Cylinder 8 fuel injector with the engine running. Compare it to adjacent injectors.
How to Diagnose P0284
- 1Check for other related codes, especially P0308 (Cylinder 8 Misfire) or P0208 (Cylinder 8 Injector Circuit/Open).
- 2Visually inspect the wiring harness and connector for Cylinder 8's fuel injector for any obvious damage, fraying, or corrosion.
- 3With the engine running, use a mechanic's stethoscope or a long screwdriver to listen for a distinct clicking sound from the Cylinder 8 fuel injector. A lack of clicking indicates it's not firing.
- 4Using a multimeter, test the resistance of the Cylinder 8 fuel injector. Compare it to the specifications in your vehicle's service manual and to other injectors on the same fuel rail.
- 5Check for voltage at the injector connector with the key on and engine off. You should see battery voltage on one wire. The other wire is controlled by the PCM for pulsing.
- 6If resistance and voltage are good, perform a 'noid light' test on the injector connector to confirm the PCM is sending a pulse signal.
- 7If all electrical tests pass, swap the Cylinder 8 injector with an injector from another cylinder (e.g., Cylinder 7). If the code moves to the new cylinder (e.g., P0283), the injector is faulty. If the code remains P0284, the issue is likely wiring or the PCM.
P0284 on Popular Vehicles
Ford F-150
2004-2010Ford F-150s with the 5.4L Triton engine are known for fuel injector failures, sometimes leading to P0284. The injectors can stick open or closed.
75% fixed by replacing the injector
Chevrolet Silverado
2007-2013On Silverado models with 5.3L or 6.0L engines, when P0284 appears, it's usually a failed injector or a corroded connector at the injector.
65% fixed by replacing the injector
Honda Accord
2003-2012While less frequent, P0284 on V6 Accord engines often points to a failed injector. Wiring issues are less common but should still be checked.
70% fixed by replacing the injector
Frequently Asked Questions
What does P0284 mean?
P0284 indicates that the Powertrain Control Module (PCM) has detected a low voltage condition in the electrical circuit for the fuel injector on Cylinder 8. This means the injector is not receiving the correct power to operate properly.
Can I drive with P0284?
No, stop driving if your Check Engine Light is flashing. A flashing light indicates a severe misfire that is actively damaging your catalytic converter. If the light is solid, limit driving to essential, short trips only.
Will P0284 clear itself?
No, P0284 will not clear itself. This code points to a hard fault in the injector circuit. The underlying issue must be diagnosed and repaired before the code will clear, either automatically after several drive cycles or by using an OBD-II scan tool.
How do I fix P0284 myself?
Start by visually inspecting the Cylinder 8 injector wiring. If no damage is found, test the injector's resistance with a multimeter. If the resistance is out of specification, replace the Cylinder 8 fuel injector. If resistance is good, use a noid light to check for a pulse signal from the PCM.
How much does it cost to fix P0284?
A DIY repair typically costs $100-$300 for a new fuel injector. Professional repair at a shop will cost $250-$700, which includes parts and labor for diagnosis and replacement.
P0284 keeps coming back - why?
If P0284 returns, it means the initial repair did not address the root cause. Common reasons include a faulty wiring harness that was overlooked, a new injector that is also defective, or in rare cases, a failing PCM driver for that specific injector.
Will P0284 fail emissions/smog test?
Yes, P0284 will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on, regardless of the code, is an automatic failure in most jurisdictions.
What's the difference between P0284 and P0308?
P0284 specifically indicates an electrical issue with the Cylinder 8 fuel injector circuit (low voltage). P0308 indicates a general misfire detected on Cylinder 8, which could be caused by the injector, spark plug, ignition coil, or even mechanical engine issues. P0284 is a more specific diagnostic code pointing directly to the injector's electrical function.
P0284 on Ford F-150?
On Ford F-150s, especially those with the 5.4L Triton engine, fuel injector failures are common. The code P0284 often points directly to a failed injector on cylinder 8. It's important to check for fuel leaks around the injector as well.
Questions to Ask Your Mechanic
Did you test the resistance of the Cylinder 8 fuel injector and compare it to others?
Good answer: Yes, the Cylinder 8 injector measured X ohms, while the others were Y ohms, indicating an internal fault.
What did you find when checking the voltage and pulse signal at the Cylinder 8 injector connector?
Good answer: We confirmed battery voltage on one wire and a consistent pulse signal from the PCM on the other, ruling out wiring and PCM issues.
Repair Cost Estimate
DIY Repair
Parts only
$100-$300
Shop Repair
Parts + labor
$250-$700
Save $150-$400 by doing it yourself
Difficulty
intermediate
Time
1-3 hours
Intermediate - requires specific diagnostic tools like a multimeter and potentially a noid light, along with careful handling of the fuel system.
Cost of Waiting
Ignoring P0284 and continuing to drive with a misfiring Cylinder 8 will send unburned fuel into your exhaust system. This rapidly overheats and destroys your catalytic converter, which is an $800-$2,500 repair. A $100-$300 fuel injector fix now prevents a much larger bill later. Prolonged misfires can also dilute your engine oil with fuel, leading to premature engine wear.
While You're In There...
If removing the fuel rail to access the injector, replace all fuel rail O-rings to prevent future fuel leaks, as they are accessed during the same labor.
If the misfire has been ongoing, the spark plug in Cylinder 8 may be fouled. Inspect or replace it, as it's easy to access once the injector is out.
Tools You'll Need
- OBD-II Scan Tool
- Multimeter
- Basic hand tools (sockets, wrenches, screwdrivers)
- Fuel injector puller (some vehicles require this)
- Noid light set (for checking injector pulse)
- Safety glasses
- Shop rags
P0284 is a specific code pointing directly to a fuel injector issue, which is a common and straightforward repair. Most repairs are under $300 and will restore your engine's performance and fuel economy.
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Your Next Steps
Step 1: Visually inspect the Cylinder 8 fuel injector's wiring and connector for any damage or loose connections. Ensure it's securely plugged in.
Step 2: If the wiring looks good, use a multimeter to test the resistance of the Cylinder 8 fuel injector. If the resistance is outside the manufacturer's specification or significantly different from other injectors, replace the injector.
Step 3: If the injector resistance is good, use a noid light to confirm the PCM is sending a pulse signal to the injector. If there's no pulse, the issue is either wiring between the PCM and injector, or a faulty PCM.