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What Is An Injector Circuit Malfunction?

What Is An Injector Circuit Malfunction

Injector circuit malfunction will show up as a certain code in your car as a diagnostic issue that you will need to use a tool to decipher – the code will come up as P0200 – injector circuit malfunction. 

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Code P0200

If you are trying to decipher “what is an injector circuit malfunction?” code in your car, you need to know how to diagnose code P0200. P0200 is a generic OBD-II diagnostic trouble code that is similar to other codes, like the P0201, P0203, P0204, P0205, P0206, P0207, and P0208. Since all of these codes are in relation to the engine, these are classified as engine misfire codes or engine lean or too rich mixtures.

Code P0200 Meaning

P0200 means that the engine control module has detected a malfunction in the fuel injector circuit. The fuel injector circuit is what is in control of the fuel injectors and determines how much fuel should be added and when to add the fuel.

Engine Control Module Function

The engine control module is the computer of your car that determines the optimal engine performance. The engine control module gains data from various sensors within your car and uses multidimensional maps. After each reading analyzing your car, the engine actuators are then adjusted to determine what needs to be fixed in your vehicle. Answering the question of “what is an injector circuit malfunction?” helps you determine if your ECM is working. 


The ECM is in charge of regulating the four main parts of your vehicle’s operating systems, including the air to fuel ratio, idle speed, valve timing, and ignition timing. The electronic control module uses sensors to regulate how much oxygen to fuel ratio is detected within your car’s exhaust and determine whether the reading is too lean or too rich within the air to fuel ratio.


Some of these sensors within the electronic control module are the mass airflow sensor, oxygen sensor, air to fuel sensor, and determining the crankshaft and camshaft to track your vehicle’s RPM and engine load by monitoring the speed. Since the engine control module determines the injector circuit malfunction, this plays a huge part in the diagnosis to answer the question “what is an injector circuit malfunction”?

Fuel Injection 

In addition to the engine control module, the fuel injectors are also involved. They command how much fuel to spray and add to the fuel injector circuit. The fuel injection is the introduction of fuel in the internal combustion engine by using the injector. The benefits of using fuel injection include smoother and more consistent throttle response, like easier starting, accurate adjustment, and air pressure changes.


The inclusion of fuel injector within the P0200 trouble code process helps to answer the question of “what is an injector circuit malfunction?”


The code P0200 is set when the electronic control module detects sensor performance out of the range for either the voltage or the resistance within the injector circuit. The ECM can trigger the failsafe mode to prevent any issues to prevent damage, and this will continue happening until the error code is fixed.

Cause of Injector Circuit Malfunction

The causes of the P0200 code vary depending on the root issue and what mechanics are involved. Answering this question can help provide clues to “what is an injector circuit malfunction?”

  • Rough Engine Idle

There are many symptoms of a failing injector within the circuit. One of the symptoms is a rough idle or the engine stalls. Since your vehicle is not getting enough fuel to power your engine, then the RPM while idling can be below the optimum performance levels and can cause rough idle or shaking idle


If the RPM gets too low in your car and prevents the engine from working properly, the car will be able to stall, and you will need to restart the vehicle. The car’s stalling can harm the engine and cause a lot of problems, not answering the question of “what is an injector circuit malfunction?” 

Rough Engine Idle Causes 

Shaking – You can tell your vehicle is having a rough idle when cold if there is a shaking and bouncing sensation in the vehicle, and you feel like the car is vibrating too much while your car is not moving. Although some cases are less severe than others, the rough idle is usually pretty identifiable by the driver. Fixing rough engine idle can help you answer the question of “what is an injector circuit malfunction?”


Vacuum Leak – Over time, these hoses can succumb to wear and tear and become damaged over time or develop a leak. If too much air gets mixed in with the fuel, then this can cause the engine to misfire, resulting in a rough idle when cold and causing you to question, “what is an injector circuit malfunction?”


Spark Plug Damage – If the engine’s damage and the spark plugs are severe enough, you might also notice that your engine has begun running rough while driving or has a rough idle when cold. Make sure when you're driving or sitting in your car that you pay attention to any jerks from your car or shaking while you are driving.

  • Engine Vibration 

The second symptom of injector circuit malfunction is that the engine vibrates. A faulty fuel injector within the circuit will cause the cylinder to misfire or not be able to fire. Engine vibration means that while you are driving, the engine can vibrate or shake after it tries to complete the respected cycle without enough fuel to use. 

Cause of Engine Vibration

Loose Hoses – If you have a loose, shaky hose, not tight, or disconnected, this can be another common sign and cause of engine vibration. A loose air hose or vacuum can lead to excessive shaking and engine vibrations and is something you will feel while driving along the road. 


To fix this issue in your car, you might need to look under the hood for any disconnected hoses and reattach them when you find the connections that are loose or no longer connected fully. Fixing the loose hoses can help you provide the solution to “what is an injector circuit malfunction?”


Broken Motor Mounts – If your car starts shaking and starts shaking so bad you can’t drive your car, this is usually a telltale and clear sign that motor mounts or the transmission in your car is damaged, broken, and not working well. 


A good way to tell that this is the problem with your engine vibration in your car is to put your vehicle in neutral and see if the engine vibration decreases. If the problem decreases as you put your car in neutral, then this is a sign that there is a problem with your motor mounts, and you need to take your vehicle to a professional at a shop to adjust the mounts to fix the vibrations

  • Engine Stalling

The next symptom of the injector circuit malfunction of a failing injector is that the engine will stall, and you will have issues accelerating. If the engine does not get enough fuel into the clogged injector, the engine will misfire and cause you to look into the answer of “what is an injector circuit malfunction?”

Causes of Engine Stalling

Bad Battery – A bad battery is one of the most common reasons your car will stall while driving. The car battery is the rechargeable battery that supplies the necessary electrical current to a motor vehicle, with the main purpose to feed the starter, which in turn powers and starts the engine to run your car. 


If the battery is dead, your car will not start. Furthermore, you might not even know that when your battery is undergoing damage or going back, it can also cause the car to stall while driving. 


Fuel Pump – The second cause of your car stalls while driving is that there is something wrong with your fuel pump. The first time you will notice a problem with a fuel pump is that the car can stall while driving and cause you not to restart the car. 


The fuel pump might show signs of why the car stalls while driving, like a slight buzzing noise while it is running. If you do not hear any noises during the fuel pump being engaged, you likely have a bad fuel pump. 


Gas With Too Much Moisture – When there is too much moisture in the fuel, it does not burn properly and can disrupt the engine’s performance, causing the car to stall while driving. If your car is running fine until you fill up your gas tank, the problem is usually caused by moisture in the gas, which can be fixed in two ways. 


The first way is to drain the gas tank and then fill it up with fresh gas clear of debris. The second way is to drive your car until all of the bad gas is used. 

  • Check Engine Light

The fourth symptom of a filing injector within the circuit that can cause the injector circuit malfunction is that the check engine light turns on. The most obvious sign of a problem is when the Check Engine light comes on and shows that the injector is not delivering enough fuel to the engine and causing inefficiencies.

  • Fuel Leak

Another sign of a failing injector is the fuel leak. A fuel leak can make you wonder what an injector circuit malfunction is – luckily, we can solve this issue. Your fuel injector might be damaged from old age, and the gasoline will leak out of the cracked or ripped tube, preventing the fuel from reaching the nozzle and will leave the engine body. 

  • Engine Surge

Another sign of a fuel injector failing is the engine surge. If the fuel injector is spraying too much fuel, this can create a huge jump in the engine, causing your acceleration to be very slow and not speed up the car enough. A failing fuel injector can cause an injector circuit malfunction and help you diagnose the real problem behind the question of “what is an injector circuit malfunction”?

  • Open Injector

Another cause of the P0200 code that can cause an injector circuit malfunction is an open or shorted injector. The electrical circuit is “open” and not closed, meaning that the electrons will not flow, and be due to an injector coil itself being broken. Similar to that, an injector wiring harness being open or short and causing the injector circuit malfunction.

  • Faulty Electronic Control Module

The last cause of the P0200 code and injector circuit malfunction is a faulty electronic control module. As we know, the ECM is the computer of the car and can control various components and mechanics. Without a working ECM, the injector circuit malfunction will occur.

Diagnosing the Injector Circuit Malfunction

“What is an injector circuit malfunction” can be answered by a technician diagnosing the issue and the P0200 code. 

  • Check for Trouble Codes 

The mechanic will check for any codes present in the vehicle and analyze the freeze frame data that is attributed to each diagnostic trouble code they will then clear the codes present in your car. After they have cleared the codes, they will perform a vehicle test under the conditions that caused the code. 

  1. Inspect the Wiring Harness

After the test drive, the mechanic will inspect the wiring harness and fuel injectors to check for any damage or broken parts, broken components, and loose connections that are not secure. He will then use a scanning tool that can diagnose the code and observe the fuel injector operation and look for any irregularities or damage on the injector circuit malfunction. 

  • Check the Voltage

The next step is to check the voltage at each end of the fuel injector. The mechanic will then install light to test the fuel injector operation. Lastly, they will perform the ECM test to make sure each part is working as intended. 

  1. Obtain Diagnostic Tools

Several tools are needed to diagnose the P0200 properly. The presence of the P0200 code means that it would be best to take the car to the mechanic instead of doing the fix yourself or trying to diagnose the code on your own. An advanced scan tool can check for the fuel injectors’ right operation and monitor through the ECM to ensure the computer is working in the right way. 


These scan tools can give data to the mechanic about the voltage, the injector resistance, and any malfunctions occurring. 


Finding the answer to “what is an injector circuit malfunction” can help you keep your car running at a high-level for a long period of time! 

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