P0204
Fix within a few daysThe engine computer detected an electrical problem with the fuel injector circuit for cylinder #4.
Code P0204 means the engine computer detected an electrical problem with the fuel injector circuit for cylinder #4. Common causes: Faulty fuel injector (60%), wiring harness damage (25%), connector issues (10%). Drivability: Yes, for short trips only. Repair cost: $50-$200 DIY, $150-$500 professional.
Can I Drive With P0204?
Yes, for short trips only
Essential trips under 10 miles, avoid highways and heavy acceleration. Fix immediately to prevent further damage.
Stop driving immediately if: Flashing Check Engine Light, significant power loss, loud knocking noises, or a strong smell of raw fuel.
Symptoms of P0204
- 1Check Engine Light is on
- 2Engine misfire or rough idle
- 3Reduced engine power
- 4Poor fuel economy
- 5Engine hesitation or stumbling
Common Causes of P0204
Parts most likely causing this code, ranked by probability
The fuel injector for cylinder 4 has an internal electrical fault, such as an open or short circuit, preventing it from operating correctly.
60% of P0204 cases are fixed by replacing the fuel injector for cylinder 4
Damaged, corroded, or disconnected wiring in the harness leading to the cylinder 4 fuel injector prevents proper electrical signal transmission.
25% of P0204 cases are fixed by repairing or replacing the wiring harness
A loose, corroded, or damaged electrical connector at the cylinder 4 fuel injector disrupts the circuit's integrity.
10% of P0204 cases are fixed by repairing or replacing the injector connector
A faulty driver circuit within the engine computer (ECM/PCM) for cylinder 4's injector fails to send the correct electrical pulse.
5% of P0204 cases are fixed by replacing the engine control module
Check These First (Before Buying Parts)
- Visually inspect the wiring harness and electrical connector for cylinder #4's fuel injector for any signs of damage, fraying, corrosion, or looseness.
- Listen for a distinct 'clicking' sound from the cylinder #4 injector using a mechanic's stethoscope or a long screwdriver placed against the injector body while the engine is running. Compare it to other injectors.
How to Diagnose P0204
- 1Visually inspect the wiring and connector for cylinder #4 fuel injector for any obvious damage, corrosion, or looseness.
- 2Use a noid light to check for a pulse signal at the cylinder #4 injector connector while the engine is cranking or running.
- 3Measure the electrical resistance of the cylinder #4 fuel injector and compare it to specifications and other injectors.
- 4If the noid light shows no pulse, check for continuity in the wiring from the ECM/PCM to the injector connector.
- 5If the injector resistance is out of spec, or if the noid light test passes but the engine still misfires, swap the cylinder #4 injector with an injector from another cylinder (e.g., cylinder #1) and see if the code moves.
- 6If all other checks pass and the code persists, diagnose the ECM/PCM.
P0204 on Popular Vehicles
Ford F-150
2004-2024Ford F-150s, particularly those with the 5.4L engine, are known to have fuel injector failures that trigger P0204. The wiring harness can also be susceptible to damage from heat and vibration.
75% fixed by replacing injector or repairing wiring
Chevrolet Silverado
2007-2024On Chevrolet Silverados, P0204 is frequently traced back to a failed fuel injector or a corroded/damaged connector at the injector. Rodent damage to wiring harnesses is also a known issue in some areas.
70% fixed by replacing injector or connector
Honda Accord
2003-2024While less common than on trucks, P0204 on Honda Accords usually points to a faulty fuel injector. Wiring issues are less frequent but should still be checked thoroughly, especially for any signs of chafing.
60% fixed by replacing injector
Frequently Asked Questions
What does P0204 mean?
P0204 indicates that the engine's computer has detected an electrical malfunction in the circuit that controls the fuel injector for cylinder #4. This means the computer is not seeing the expected electrical signal from or to that injector.
Can I drive with P0204?
Yes, for short trips only. You can drive your vehicle for essential, short trips, but you must fix this code within a few days. A misfiring cylinder sends unburned fuel into the exhaust, which can quickly damage your catalytic converter.
Will P0204 clear itself?
No, P0204 will not clear itself. This code indicates a hard electrical fault that requires diagnosis and repair. The Check Engine Light will remain on until the underlying issue is resolved and the code is cleared, either manually with a scan tool or after several drive cycles once the fault is fixed.
How do I fix P0204 myself?
Start by visually inspecting the wiring and connector for cylinder #4's fuel injector. If no damage is found, use a noid light to check for a pulse at the injector connector. If there's no pulse, test the wiring for continuity. If there is a pulse, test the injector's resistance. If the injector is faulty, replace it. If the wiring is bad, repair it.
How much does it cost to fix P0204?
DIY repair costs for P0204 are typically $50-$200, primarily for a new fuel injector and potentially a noid light or multimeter. Professional repair at a shop usually costs $150-$500, covering parts and 1-2 hours of labor.
P0204 keeps coming back - why?
If P0204 keeps returning, it indicates the initial repair did not address the root cause. Common reasons include a faulty replacement injector, an intermittent wiring issue that was missed, a problem with the injector's connector, or, less commonly, a failing engine control module (ECM/PCM) driver for that cylinder.
Will P0204 fail emissions/smog test?
Yes, P0204 will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on is an automatic failure in most jurisdictions. Additionally, a misfiring cylinder increases harmful emissions, which would also result in a failed test.
What's the difference between P0204 and P0304?
P0204 specifically indicates an electrical circuit malfunction with the fuel injector for cylinder #4. P0304 indicates a general misfire detected in cylinder #4. While a P0204 will almost always cause a P0304, a P0304 can be caused by many other issues like a bad spark plug, ignition coil, or low compression, not just an injector circuit problem.
P0204 on Ford F-150?
On Ford F-150s, especially those with the 5.4L Triton engine, P0204 is often caused by a faulty fuel injector. The wiring harness and connectors are also common failure points due to heat and vibration. Diagnosis should always start with checking the injector's electrical integrity and the wiring.
Questions to Ask Your Mechanic
Did you perform a noid light test on the cylinder #4 injector connector to confirm a pulse?
Good answer: Yes, I confirmed there is (or isn't) a pulse. If no pulse, I checked continuity back to the ECM. If there is a pulse, I moved on to testing the injector itself.
What was the resistance reading of the cylinder #4 fuel injector, and how did it compare to the other injectors?
Good answer: The resistance was [X ohms], which is [out of spec/within spec] compared to the other injectors which were all around [Y ohms]. This indicates [a faulty injector/the injector is likely good].
Repair Cost Estimate
DIY Repair
Parts only
$50-$200
Shop Repair
Parts + labor
$150-$500
Save $100-$300 by doing it yourself
Difficulty
intermediate
Time
1-3 hours
Intermediate. This repair requires basic electrical diagnostic skills, a multimeter, and potentially a noid light. Accessing the injector may require removing the intake manifold on some vehicles.
Cost of Waiting
Ignoring P0204 and the resulting misfire sends unburned fuel into your exhaust system. This causes your catalytic converter to overheat and melt internally, leading to a complete failure. A $50-$200 fuel injector repair now prevents a $800-$2,500 catalytic converter replacement later.
While You're In There...
If the intake manifold must be removed to access the fuel injectors, replacing the gasket prevents vacuum leaks and ensures a proper seal upon reassembly.
A prolonged misfire can foul the spark plug in cylinder #4. Replacing it ensures optimal combustion once the injector issue is resolved.
Tools You'll Need
- OBD-II Scan Tool
- Multimeter
- Noid Light Set
- Basic Hand Tools (sockets, wrenches)
- Fuel Injector Puller (some vehicles)
P0204 is a common electrical fault for a single fuel injector. Most repairs are straightforward, and your engine will run smoothly and efficiently once the issue is resolved.
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Your Next Steps
Step 1: Perform a thorough visual inspection of the cylinder #4 fuel injector's wiring and connector. Look for cuts, chafing, corrosion, or a loose connection.
Step 2: Use a noid light to confirm if the injector is receiving an electrical pulse. If no pulse, test the wiring for continuity. If there is a pulse, proceed to test the injector itself.
Step 3: If the wiring and pulse are good, measure the resistance of the cylinder #4 fuel injector. If it's outside specifications or significantly different from other injectors, replace the injector. Parts you'll likely need: one fuel injector for cylinder #4, possibly an intake manifold gasket set.