In this comprehensive guide, we aim to provide a profound understanding of Polaris code 65590 and delve into the possible causes of this engine code and the potential causes and solutions.

The purpose of Polaris engine codes, also known as diagnostic trouble codes (DTCs), is to offer a standardized method of locating and evaluating problems with the Polaris’s engine and related systems. Polaris’ vehicles typically come with an ECU, with some exceptions, particularly the models with advanced electrical systems equipped with a PCM. And these engine codes are generated by the ECU or PCM when it detects anomalies within the engine.

One such code you can run into with your Polaris is the Polaris code 65590. This engine code indicates that misfires are occurring when your engine is running. Similarly, DTC codes 65591 and 65592 also denote engine misfires.

So, if you are a Polaris owner, or someone looking to own a Polaris in the future, it is wise to know what is Polaris code 65590 and its causes, and how to fix it.

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The Connection Between Codes 65590, 65591 And 65592.

Codes 65591 and 65592 are more specific, as they distinguish which cylinder is misfiring.

Polaris Code 65591

The DTC code 65591 indicates that there is a misfire detected in cylinder 1, which is the PTO (Power take off) where the clutch commits power to the driveshaft.

Polaris Code 65592

DTC code 65592 indicates that a misfire is detected in cylinder 2. The other side of the engine, MAG (Magneto side).

Engine misfiring is a frustrating issue that can prevent any vehicle, including the Polaris models, from operating smoothly. Not only does it affect ride quality, but it could also cause irreparable damage to your engine if left unchecked.

Also read: Polaris UTV Reliability, Check Your Model Here!

What Happens When The Code Appears On your dash?

When the code appears on your dashboard, the engine will most likely go into limp mode. If your vehicle is in limp mode, the engine power is limited, and you cannot drive fast or accelerate quickly.

This is done to protect your vehicle from greater damage. You can still drive, but then preferably home or to the garage. If possible, stop the vehicle and take it to a garage.

Also read: Polaris Limp Mode Reset, And What Causes It to Activate?

Causes Of Polaris Code 65590

As mentioned earlier, the Polaris code 65590 indicates a misfire and in the case of misfires, there are multiple causes. Here are some of the most common causes of Polaris code 65590 and what you should do to get the problem solved.

Faulty Throttle Position Sensor

A faulty throttle position sensor (TPS) is one of the common reasons for engine misfiring. The TPS is in charge of keeping track of how the throttle plate is situated in relation to the driver’s input. And it provides this information to the ECU or PCM. With this information, the ECU or PCM can control the flow of fuel and air into the engine as needed.

With a faulty TPS, the information sent to the ECU or PCM will be incorrect. This would lead to the engine receiving the wrong fuel and air mixture, which would lead to misfires.

How To Fix:

The easiest way to diagnose the issue is through a scan tool. The scan tool will show specific codes when the TPS is damaged. By retrieving these codes, you can ensure that the problem is indeed the TPS. A physical inspection is also a valid way to diagnose the problem. Often when the TPS is malfunctioning, it is physically damaged.

Once you conclude that the problem is indeed the TPS, you need to get it replaced. You can locate it with the help of the owner’s manual. Depending on the model, it might be held up by bolts or screws. Once you remove it, all you have to do is swap it out with the new TPS.

A new TPS could cost anywhere from $50 to $150. Once you replace your TPS, clear out the error codes, and you are good to go.

Also read: Are Polaris ATVs Reliable, Check Your Model Here!

Slipping Belt

I have a 2019 Ranger 1000 XP EPS with 750 miles on it and 90hrs. It was throwing a misfire code 65590 and 65592 with a small 7 at the bottom of the display. Many say it’s caused by a slipping belt, but this code has been showing up for some time immediately after a cold start and sometimes stays in the print mode, sometimes not.

So, the big question is: Can a slipping belt cause your engine to misfire? The primary function transfers power from the engine’s crankshaft to various other components like the alternator, water pump, power steering pump, and a few other components. Though a slipping belt will not directly cause engine misfires, it will disrupt the function of other components in your Polaris, which could lead to misfires.

If your alternator belt slips, it might result in insufficient charging in your vehicle. This could lead to weak sparks through your spark plugs, which could result in misfires. Similarly, if your water pump doesn’t function properly, your engine will overheat. This could cause irregular combustion and misfires.

I have had it happen when the spider on my primary came loose, which caused it to hit the rev limiter at 45 mph. Most likely just time to replace the belt.

Though a slipping belt doesn’t directly cause engine misfires, when looking at Polaris code 65590, the Polaris belt is a common suspect.

How To Fix:

If a slipping belt is causing your Polaris to misfire, your best bet is to get it replaced. Depending on the make and model of your Polaris, you should expect to spend $100 to $300 to get your Polaris belt replaced.

Ignition System Issues

Unlike the Polaris belt, ignition system issues directly cause misfires. The ignition system is responsible for delivering a high-voltage spark that ignites the fuel-air mix inside the engine. And without this spark, the fuel-air mixture inside your combustion chamber doesn’t ignite, which directly results in a misfire.

Your ignition system consists of many components such as the spark plug, ignition coil, wiring, ignition switch, and many more. Even if one of these fails, your engine will misfire, shut down, or not start at all.

How To Fix:

Though there are many components in the ignition system, if your Polaris is displaying code 65590, chances are the problem is associated with the spark plugs. Standard copper spark plugs only last around 20,000 miles, while premium options like iridium plugs can push 60,000. Depending on the type of spark plugged equipped in your engine, you need to get them replaced when needed.

Even a dirty spark plug can cause engine misfires. So, regular maintenance and cleaning of spark plugs is a good practice. If the spark plugs are fine and your engine is still misfiring, you should check your wires and ignition coil and replace them if needed.

Loose Spider Nut

The spider nut is a large nut in the center of the primary clutch. This nut secures the spider assembly, which contains the clutch weights and arms. This nut is crucial for proper clutch engagement and transfer of power. If the spider nut on your primary loosens, it could cause misfires among other performance issues.

This is quite rear when comparing it to a slipping belt, but the symptoms are quite similar.

How To Fix:

The main complication with a loose spider nut is accessing it. Depending on the model of your Polaris you might need to remove the clutch cover or other components along with it to reach the primary clutch. Once the spider nut is in sight, inspect it for damage. If you see signs of wear or damage, you should go ahead and replace the nut. Or if the nut is just loose, acquire the appropriate tools and just tighten it.

The next video is about how to troubleshoot misfire codes 65590.

Fuel System/ Air Intake Problems

This is another common reason why your engine is misfiring. Your combustion chamber needs the right amount of air and fuel for complete combustion. If your engine is not getting enough clean air and fuel, your engine won’t be able to produce enough power, thus causing misfires.

How To Fix:

Unlike the other problems, if your Polaris code 65590 pops up due to fuel system or air intake issues, there can be numerous causes. Clogged fuel injectors, a malfunctioning fuel pump, or a dirty fuel filter can disrupt fuel delivery, causing misfires. Similarly, a clogged air intake or dirty air filter can lead to a lean air-fuel mixture, again, causing misfires.

Often when any of the above parts are affected, along with Polaris code 65590 you would also see other error codes. Thanks to the owner’s manual and a scanner tool, you can get to the root of the problem and get it fixed.

Other Possible Causes

The most obvious causes are listed above. However, there can also be other causes causing the problem, such as:

Valve related issues. You can check the pressure in the cylinder, it should be between 150 and 180 lbs.

A failing crankshaft position sensor, which cannot provide the right information about piston positioning in the engine, causing a cylinder to misfire.


The Polaris code 65590 or accompanying codes 65591 and 65592 indicate misfires in your engine. This code could be a result of a slipping belt, a faulty throttle position sensor, or any of the issues mentioned above.

By understanding the underlying causes of engine misfires and knowing how to address them, as a Polaris vehicle owner, you can take proactive steps to maintain the performance and reliability of your vehicles.