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Summary
  • The Diagnostic Trouble Code (DTC) P0204 stands for “Injector Circuit Problem—Cylinder 4.”
  • A dormant injector will have a voltage close to the battery voltage, whereas an active one will have a voltage that is “low” near zero. The PCM will set the P0204 code if the injector’s voltage does not match the voltage expected for its state.
  • A P0204 code can cause engine misfires, reduced acceleration, rough running, and poor fuel economy.

Fuel injectors spray atomized fuel into the cylinders or intake manifolds of internal combustion engines with an electronic fuel injection system. To activate the injector, the computer that controls the engine energizes the injector’s driver. An energized driver forms a closed circuit that moves the injector’s valve to the open position.

If the engine control module (ECM) or powertrain control module (PCM) detects a problem with the cylinder four fuel injector or its circuit, it will set a P0204 code.

What Does the P0204 Code Mean?

The Diagnostic Trouble Code (DTC) P0204 indicates “Injector Circuit Problem—Cylinder 4.” 

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Each fuel injector possesses a solenoid-operated valve that allows pressurized fuel to flow out of the part. A special transistor called a “driver” controls the valve. Energizing the driver creates a closed circuit and moves the valve to an open position.

technician inspects one fuel injector
Fuel injectors spray atomized fuel into the cylinders or intake manifolds of internal combustion engines with an electronic fuel injection system.

The engine computer, which is often referred to as the powertrain control module (PCM), keeps track of injector operation. A dormant injector will show a voltage close to battery voltage while an active one will pull its voltage to a “low” value near zero. If the injector’s voltage does not match the voltage expected for its state, the PCM will set the P0204 code.

The PCM also measures the circuit’s electrical resistance. It will set a P0204 code if the resistance is much higher or lower than it should be.

Read our technical discussion about fuel injection for a broader background on how codes like P0204 can come about.

Note: The definition of code P0204 may differ according to the vehicle manufacturer. Check the right repair manual or repair database for the exact code definition.

What are the Possible Causes of the P0204 Code?

  • Worn-out or faulty fuel injector
  • Powertrain Control Module (PCM) issue 
  • Circuit problems, such as damaged wires and loose connections 

What are the Common Symptoms of the P0204 Code?

  • Decreased engine performance, including:
    • Engine misfire
    • Engine runs roughly
    • Reduced acceleration
  • Increased fuel consumption
  • Check engine light switches on
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How to Diagnose the P0204 Code

A DTC P0204 is a generic trouble code that may be logged in vehicles from different auto manufacturers. While these vehicles may display similar triggers and symptoms, the steps for diagnosis and repair may differ according to their make and model.

If you’re not sure about your ability to run diagnostic tests on your vehicle, consider bringing it to a professional mechanic. Otherwise, you might consider diagnosing the issue yourself. To help you get started, here is a video  that may give you an idea of what the process might involve:

How to Fix the P0204 Code

Attempting to fix a P0204 code may prove frustrating if you lack the right tools and know-how to test the fuel injector and its circuit. In most cases, it’s best to leave the job to professionals.
For DIYers with advanced technical knowledge and hands-on experience who prefer to test and replace their vehicle’s fuel injector on their own, it will be helpful to rely on repair manuals or repair databases.

Where to Get a New Fuel Injector for Your Vehicle

Driving with a P0204 code due to a malfunctioning fuel injector is dangerous, as it leads to various engine issues, such as misfires. Getting engine repairs are expensive, so why not nip the issue in the bud? Shop with CarParts.com to get the replacement piece you need.

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Shop for new fuel injectors from the comfort of your home using your phone or laptop to visit CarParts.com. Use our website’s vehicle selector tool to narrow down the catalog to compatible fuel injectors. We partnered with trusted manufacturers to ensure the replacement pieces you buy are of quality. And because our warehouses are strategically located across the country, you can expect to get your order in as fast as two business days.

Don’t wait for your engine to misfire before replacing your fuel injector. Get a top-notch replacement at CarParts.com today!

Shop this Project

Replacement – Fuel Injector, with Red Connector
, P0204 Code: Injector Circuit Problem – Cylinder 4
$17.49 Price and rating may change from the time content is published.
Replacement – Fuel Injector, Blade Type, 2-Prong Male Terminal, Includes O-Ring
, P0204 Code: Injector Circuit Problem – Cylinder 4
$21.54 Price and rating may change from the time content is published.
Replacement – Fuel Injector – New, Sold individually
, P0204 Code: Injector Circuit Problem – Cylinder 4
$17.49 Price and rating may change from the time content is published.
About The Authors
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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