I have an open circuit code on the fuel injector on cylinder 3.

My car is a pontiac grand prix GTP 1999. Do you know what controls the fuel injectors?

My car has 144000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
Hi there. From the description you have provided, your vehicle has an open circuit code on the #3 fuel injector, is going to require circuit testing. The fuel injector(s) are controlled by the injector driver(s) in the ECM (engine control module). Battery voltage is supplied to all of the fuel injectors and the ground side is controlled by the ECM. It could be, a poor connection or wiring problem at or to the #3 fuel injector. There is a noid light available that plugs into the connector, to check for proper signal while cranking. It could be, the #3 fuel injector coil is open.

Measuring the resistance value between the fuel injector terminals could confirm the fault. It could be, the injector driver has failed in the ECM. I recommend having your vehicle’s open circuit code on the fuel injector on cylinder 3 – check engine light on be diagnosed and repaired by a certified technician, such as one from YourMechanic.

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A defective fuel injector or a problem with the circuit itself are both very common causes of these codes. In some cases, you might see an issue with the PCM or a problem with the battery voltage, although these will usually cause other codes to fire and are less common.
What Does the P0203 Code Mean? Diagnostic trouble code (DTC) P0203 stands for “Injector Circuit/Open – Cylinder 3.” The powertrain control module (PCM) may set this code if it has detected a potential error in the injector or the injector wiring. It may also register this code if it can`t control the fuel injector.
Diagnostic trouble code (DTC) code P0201 stands for “Cylinder 1 Injector Circuit/Open.” It indicates a potential problem with the #1 Fuel Injector Circuit, like a broken wire, loose terminal, burned out injector coil, or some other circuit interruption issue.
Diagnostic trouble code (DTC) P0200 stands for “Injector Circuit/Open.” This code is logged when the powertrain control module (PCM) detects a possible problem in the operation of the fuel injector circuit.
Code P0203 indicates an injector misfire on cylinder 3, with the PCM commanding the injector to open but not recognizing a change in electrical current that would indicate the injector fired.
Electronic Control Unit (ECU)

The ECU is the brain of the operation. It uses engine RPM and signals from different sensors to meter the fuel. It does this by telling the fuel injectors when and how long to fire. The ECU often controls other functions like the fuel pump and ignition timing.

Odor and Temperature:

An injector that is stuck open or partially closed will emit an unburnt fuel odor in the engine compartment. A dead injector will cause the engine start and operate when it is cold but not when it is warm.

Driving a short distance before a repair would OK if it is not very far. If the injector is stuck open and dumping fuel, then it may not even start. Dumping large amounts of unburned fuel into the engine can result in engine and or catyalitic converter damage.
The only guaranteed way to unclog a clogged injector properly is by removing the injectors from the engine. Once removed, the injectors can be dropped off or mailed to a professional injector cleaning service such as Injector RX.
P0611 is a diagnostic trouble code (DTC) for “Fuel Injector Control Module Performance”.
Common causes of injector failure

While many things can cause breakdowns, the most likely cause of premature failure is fuel contamination. Fuel contamination occurs when debris in the fuel gets past the filtration, destroying the sealing surfaces. Think microns, smaller than a human`s hair-sized, clearances.

One of the obvious symptoms of a clogged fuel injector is the lighting up of the “Check Engine” light in your dashboard. The fault codes usually associated with a clogged fuel injector can range from misfire codes to lean codes.
There are many reasons for faulty fuel injectors but the three most common issues are clogging in your car`s fuel injectors, leaky and dirty injectors. You should remove the fuel injectors and clean them up before putting them back in for your car to function optimally.
If a fuel injector has an O-ring issue or is stuck open, it will allow too much fuel to get into the combustion chamber. Since the extra fuel won`t get burned, it will exit the tailpipe in the form of white or grayish smoke.
The P0300 engine code indicates a misfiring cylinder problem in your vehicle. The misfiring happens when insufficient fuel is burned or when the spark plug gets damaged.
If the ECM detects an unexpected drop in pressure in the high-pressure side of the fuel system, mainly due to leaky fuel injectors, it will set a diagnostic trouble code (DTC) P02AD and illuminate the Check Engine Light (CEL).
Fundamentally, the engine ECU controls the injection of the fuel and, in petrol engines, the timing of the spark to ignite it. It determines the position of the engine`s internals using a Crankshaft Position Sensor so that the injectors and ignition system are activated at precisely the correct time.
The most common and relevant cause of a P0300 code is spark plugs that are damaged or worn. This is also a common cause among additional codes displayed as P030X. Spark plugs are devices that ignite the compressed mixture of air and fuel in each cylinder of an internal combustion engine.
You might get a misfire code after spark plug replacement for an individual cylinder like a P0303. The code indicates a misfire in cylinder three. Sometimes the spark plug is dropped, and the ground electrode and the center electrode can make contact. Or the problem could be with the connection to the coil.
Don`t Put Off Fuel Injector Issues

While the risk of severe engine damage is relatively low, it`s not impossible. More importantly, replacing a bad fuel injector will improve the fuel economy, engine power, and overall drivability of your vehicle.

You can! But you run the risk of burning out the catalytic converter.
Therefore, no attempt should ever be made to disconnect these injectors while the engine is running. After only a few engine revolutions enough fuel will have entered the cylinder to cause hydraulic lock and serious engine damage, not to mention the risk of electric shock.
If a clogged fuel injector continually struggles to disperse fuel to the engine, a time will come when it misses the fuel supply completely and the engine will misfire. The misfire will easily be felt while driving, and often requires immediate repair by trained automotive repair specialists.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

What would cause 1st cylinder misfire, multiple misfire, all fuel injectors circuits open and o2 sensors heater circuit high on a 2008 Dodge Charger
ANSWER : Hello. It sounds like you may have the wrong parts installed on the car. Due to the fact that multiple people have worked on it you may have some parts that do not meet specifications. From what it sounds like to me though you either do not have an ECM in the vehicle with the correct programming or you have a connection issue. If all of the grounds are not clean and tight then that will cause this. if they are then the computer needs to be programmed to your vehicle at the dealer and that may take care of it.

Fuel injector.
ANSWER : Hello, the fuel injector circuit has a ground side and power side. 12 volts would be on one side and the ground side is pulse width modulated (a variable voltage signal) controlled by the computer. A series of tests would have to be performed to locate the electrical concern. These tests require special equipment. If you’d like, a certified Your Mechanic Technician can come to your location to look at this issue. Please look at this web site for more information and service options. fuel injector circuit

I have a 1981 e-350 with dual fuel tanks the p.o. added a third tank and 3 electric fuel pumps along with sepparate gauges and swi
ANSWER : The switch you are referring to is vended with the required electrical and fuel schematic (I just looked in the box) that answers your installation question. If you want an advance view, here is a link as well. Yes, you need a return line and just refer to the aforementioned link. If you are retrofitting back to OEM, I strongly encourage you to buy the original Factory Service Manual (FSM). There are lots of details attending this system and obviously it is difficult to recount it all here. The FSM will make your life much easier and you can then make sure your installation is perfect. Alternatively, YourMechanic can dispatch a certified mechanic and perform the whole retrofit and check out if you desire. Just request and schedule a generic service such as fuel pump service and the mechanic will come to your location and estimate the parts and labor required. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Misfire cylinders 4 and 7.
ANSWER : You need to check the PCV tube that goes behind the intake and connects into the back side. The hose can get a leak in it, causing a vacuum leak on the back side. This will create lean conditions that may be worse for cylinders 4 and 7 specifically on this engine.

If the hose is good then try and have the injectors replaced or cleaned for these two cylinders. You could swap them with different cylinders to see if the problem moves along to the other cylinder, doing so will help pinpoint the issue.

If you decide to get the car looked at, consider YourMechanic, as a certified technician can come to your location and diagnose your car’s misfire. An accurate repair can then be made once the problem has been pinpointed.

I have injector circuit open on 2, 4, and 6 error codes (codes P0202, 204, and 206)
ANSWER : Hi James. I would suggest purchasing a service and repair manual for your 2006 Cadillac CTS, as it will provide you with a wiring diagram for the fuel injector wiring. It is very common on these Cadillac’s for the wiring harness to become damaged due to excessive heat, from the fuel injector, behind the engine and to the ECU. I would be proactive and replace these wiring harnesses. This should resolve the issue or confirm that you have an ECU issue; which I would wager is highly unlikely. Good luck and thanks for writing in.

I have an open circuit code on the fuel injector on cylinder 3.
ANSWER : Hi there. From the description you have provided, your vehicle has an open circuit code on the #3 fuel injector, is going to require circuit testing. The fuel injector(s) are controlled by the injector driver(s) in the ECM (engine control module). Battery voltage is supplied to all of the fuel injectors and the ground side is controlled by the ECM. It could be, a poor connection or wiring problem at or to the #3 fuel injector. There is a noid light available that plugs into the connector, to check for proper signal while cranking. It could be, the #3 fuel injector coil is open.

Measuring the resistance value between the fuel injector terminals could confirm the fault. It could be, the injector driver has failed in the ECM. I recommend having your vehicle’s open circuit code on the fuel injector on cylinder 3 – check engine light on be diagnosed and repaired by a certified technician, such as one from YourMechanic.

EGR code, Cylinder 4 misfire code 0304 detected.
ANSWER : Hi there. The Exhaust Gas Recirculation (EGR) valve may be not designed for the emissions requirements for U.S. standards. If the EGR is pulling from cylinder number 4 and after replacing the EGR and the computer detects a misfire, then the EGR is malfunctioning and not responding. When you close off the tube to the EGR and the EGR light comes on and the misfire light goes out, then the EGR is not responding to your emissions system. I recommend replacing the EGR with the OEM specified part for the engine and all of the issues should go away. If you need further assistance with your misfire and EGR, then seek out a professional, such as one from Your Mechanic, to help you.

Fuel pressure
ANSWER : Hello,
You may want to try checking the fuel pump relay. The relay wires should have ground on two wires, power on one wire and switched power on another wire. To activate the fuel pump your ECU actually connects one of the ground wires to complete the circuit and send power to the fuel pump. If the wires all have power running through them, then it is likely you have a faulty relay. The wire coming from the fuel pump is the other ground wire. I would recommend having an expert from YourMechanic come to your location to diagnose your wiring as this can be very difficult and time consuming without the proper wiring diagram.