P0204 Repair Cost: What You’ll Pay to Fix Cylinder 4

ByJason Carter August 9, 2026August 9, 2026

How Much Does P0204 Cost to Fix?

Most P0204 repairs cost between $150 and $850 on gasoline vehicles. Diesel injectors, difficult engine layouts, or a failed powertrain control module can push the bill above $1,000.

The code alone cannot produce an accurate estimate. Your shop must identify the failed part first.

These are planning ranges, not guaranteed quotes. Taxes, diagnostic charges, shop rates, and related repairs may increase the total.

A shop may apply its diagnostic charge toward the repair. Ask about that policy before authorizing work.

Cost note: Request an itemized estimate tied to your VIN, engine, and confirmed failure.

Section Takeaway: P0204 may be a modest wiring repair or an expensive injector job. Diagnosis should come before replacement.

What Does Code P0204 Mean?

P0204 means the powertrain control module detected a problem in the fuel injector circuit for cylinder 4. Many scanners describe it as “Injector Circuit/Open – Cylinder 4.”

A fuel injector is an electrically controlled valve that meters fuel into the engine. The PCM switches that injector on and off through a driver circuit.

If the expected electrical response is missing or outside the allowed range, the PCM stores P0204. The word “open” does not prove that one specific wire is broken.

What can trigger P0204?

• Failed injector coil: An internal electrical break prevents the injector from responding.
• Loose connector: Weak terminal tension can interrupt the circuit during vibration.
• Corroded terminals: Moisture creates resistance or an intermittent connection.
• Damaged wiring: Heat, rubbing, rodents, or previous repairs may harm the harness.
• Power supply fault: A fuse, relay, shared feed, or ground problem can affect injector operation.
• PCM driver fault: The module’s injector-control circuit may fail, though this is less common.

Common symptoms include rough idle, hesitation, weak acceleration, reduced fuel economy, and a cylinder 4 misfire. Related codes may include P0304 or other injector-circuit faults.

The engine may run normally when the failure is intermittent. Freeze-frame data and a wiring inspection become important in that situation.

Diagnostic note: Do not buy an injector solely because its cylinder appears in the code description.

What Changes the P0204 Repair Price?

The largest cost factor is the failed component. A connector repair takes less time and fewer parts than replacing a direct-injection or diesel injector.

Injector design and engine type

Port-fuel injectors are often easier to reach. Gasoline direct-injection systems operate at higher pressure and may require more disassembly.

Diesel common-rail injectors can be considerably more expensive. Testing, coding, calibration, and difficult removal may add labor.

Access to cylinder 4

Some injectors sit beneath an intake manifold or other components. The technician may need new gaskets and seals after removing those parts.

Cylinder numbering also varies by engine design. A technician should verify the manufacturer’s cylinder layout instead of guessing.

OEM versus aftermarket parts

An OEM part comes through the vehicle manufacturer’s supply chain. Aftermarket injectors come from independent manufacturers and may cost less.

• OEM injector: Usually offers the most direct match but may cost more.
• Quality aftermarket injector: May reduce cost when the supplier confirms exact compatibility.
• Remanufactured injector: Can be economical, but warranty and testing standards matter.
• Unknown online part: A low price can become expensive if the injector is incorrect or poorly matched.

Compatibility should be checked using the VIN, engine code, and original part information. A similar-looking injector may have different electrical or flow characteristics.

Local labor rates

Shop rates vary by region and facility. Dealerships may charge more, while an independent diagnostic shop may offer lower labor costs.

Choose based on testing ability, not price alone. A correct $150 diagnosis can prevent several hundred dollars in unnecessary parts.

Section Takeaway: Injector type, engine access, parts quality, and labor rates determine the final bill. Vehicle-specific estimates are more useful than national averages.

How Should P0204 Be Diagnosed?

A proper P0204 diagnosis tests the entire cylinder 4 injector circuit. Replacing the injector should happen only after evidence points to it.

1. Confirm the code and symptoms

The technician should record every stored and pending code. Freeze-frame data shows engine conditions when the PCM detected the fault.

Codes affecting several injectors may suggest a shared power or harness problem. P0204 by itself keeps the focus on cylinder 4.

2. Inspect the connector and harness

The connector should be checked for broken locks, backed-out pins, corrosion, oil, and loose terminals. Wiring should be inspected near brackets, hot surfaces, and previous repair points.

A gentle wiggle test may expose an intermittent fault. Any testing must follow the manufacturer’s wiring diagram.

3. Test the injector electrically

A technician may compare injector resistance with the vehicle’s service specification. There is no universal resistance value for every injector.

A noid light, lab scope, or suitable meter can help verify power and control signals. The correct method depends on the injection system.

4. Check circuit integrity

Continuity alone may miss a damaged wire that fails under load. Professional testing can reveal excessive resistance, shorts, or weak terminal contact.

The battery and module connectors may need isolation before certain tests. Following the service procedure helps protect sensitive electronics.

5. Consider the PCM last

A PCM should not be condemned until the injector, wiring, terminals, power supply, and grounds pass testing. Replacement modules may require software programming and an immobilizer relearn.

That security setup can involve the same vehicle systems used for transponder chips and smart keys. It is another reason module replacement should be handled carefully.

Safety note: Direct-injection and diesel fuel systems can retain dangerous pressure after shutdown. Leave high-pressure testing to a trained technician.

Section Takeaway: The best diagnosis follows the circuit from the injector to the PCM. Testing each point prevents costly guesswork.

Can You Drive With a P0204 Code?

You should limit driving with P0204 and arrange diagnosis promptly. A misfiring cylinder can cause poor control, stalling, and additional emissions-system damage.

A steady check-engine light does not mean the problem is harmless. The risk depends on how badly the engine runs.

Stop driving when these signs appear

• Flashing warning light: A severe misfire may damage the catalytic converter.
• Strong fuel smell: Shut the engine off and investigate a possible fuel leak.
• Heavy shaking: Continued driving may worsen the fault or leave you stranded.
• Stalling: Unpredictable engine operation creates a traffic safety risk.
• Major power loss: The vehicle may not accelerate safely.

AAA’s check-engine-light guidance treats a flashing light as an urgent warning. Pull over safely and arrange towing when the engine shakes or the light flashes.

You can also check your VIN through the NHTSA recall lookup. A related open recall could change who pays for the repair.

Safety note: Do not clear the code repeatedly to hide the warning while continuing to drive.

How Do You Choose the Right Repair?

Choose the repair supported by test results, not the cheapest part advertised online. The written estimate should identify the failed component and explain how the shop confirmed it.

Questions to ask the repair shop

• What failed? Ask whether the problem is the injector, connector, wiring, power supply, or PCM.
• How was it tested? Request a short explanation of the electrical findings.
• Is diagnosis included? Confirm whether the testing charge applies toward the repair.
• Which part will you use? Ask whether the injector is OEM, aftermarket, new, or remanufactured.
• What is covered? Check the parts-and-labor warranty in writing.
• Are extra services required? Ask about seals, gaskets, programming, calibration, and taxes.

A second estimate makes sense when the shop recommends a PCM without showing circuit-test results. It is also reasonable when several injectors are proposed for a single-cylinder electrical code.

An AAA-approved repair facility search can help you locate participating shops. You should still compare written estimates and warranties.

Before ordering a part, provide the VIN and exact engine information. That step matters for injectors just as much as matching an FCC ID matters for a replacement key fob.

Locksmith’s note: PCM replacement may affect immobilizer authorization, so confirm that programming and key relearn are included.

P0204 Repair Cost FAQ

Can a bad spark plug cause P0204?

A bad spark plug can cause a cylinder 4 misfire, but it does not normally create an injector-circuit code. P0204 points toward the injector’s electrical circuit, although separate ignition problems may exist.

Will injector cleaner fix P0204?

Injector cleaner will not repair a broken wire, loose terminal, failed coil, or PCM driver. It may help some deposit-related fuel-delivery problems, but P0204 requires electrical diagnosis.

Can I replace only the cylinder 4 injector?

Yes, shops often replace one confirmed failed injector. Some engines may benefit from matched injectors or additional testing, especially when mileage is high or the manufacturer specifies calibration procedures.

How long does a P0204 repair take?

A simple connector repair may take one or two hours. Injector replacement can take several hours when the intake manifold, fuel rail, or diesel-system components must be removed.

Can a blown fuse cause P0204?

It is possible, but one fuse commonly powers several injectors. If only P0204 appears, a cylinder-specific connector, wire, injector coil, or PCM driver is often more likely.

Does clearing P0204 fix the problem?

No. Clearing the code only removes stored diagnostic information and turns off the warning temporarily. P0204 will return when the PCM detects the circuit failure again.

Could a recall cover the repair?

A recall may cover the repair when your exact VIN has an applicable open campaign. Check NHTSA and then contact the manufacturer’s dealer for confirmation before paying.

The smartest response to P0204 is simple: pay for proof before paying for parts. Get the circuit tested, compare an itemized estimate, and address severe misfire symptoms without delay.