2017 Rzr 1000 Code 65591 Polaris Code - Your Complete DIY Diagnostic

You’re blasting down your favorite trail, engine roaring, when suddenly—a sputter. A hesitation. The dreaded check engine light flashes on your dash, and your RZR starts running like it’s on one cylinder. You pull up the diagnostics and see it: 2017 rzr 1000 code 65591 polaris code. Your heart sinks a little. A trip to the dealer means downtime and a hefty bill.

We’ve all been there. That frustrating moment when a simple code threatens to ruin a perfect day of riding. But what if that code wasn’t a death sentence for your weekend?

Here at FatBoysOffroad, we believe in empowering you to handle your own rig. We promise this guide will demystify that pesky code 65591. We’ll break down exactly what it means, show you the most common causes, and give you a step-by-step, easy-to-follow plan to diagnose and fix it right in your own garage. Let’s get your machine running strong again.

What Exactly is the 2017 RZR 1000 Code 65591 Polaris Code Telling You?

First, take a deep breath. This code is common and usually very fixable. In plain English, code 65591 is a Misfire Detection for Cylinder 1. This means the Engine Control Unit (ECU), your RZR’s brain, has detected that the spark plug in the first cylinder (the one closest to the front of the vehicle) isn’t firing correctly or that combustion is incomplete.

A misfire can cause a range of symptoms, from a rough idle and poor acceleration to backfiring and a significant loss of power. Ignoring it can lead to more serious engine damage down the line, so it’s crucial to address it.

To get more specific, Polaris often includes an FMI (Failure Mode Identifier) number with the main code. This gives you a massive clue about where to start looking.

Understanding the FMI Sub-Codes (3, 4, 5, & 7)

Think of the FMI as a detective’s note left at the scene of the crime. Here’s what the most common ones mean for code 65591:

FMI 3 or 4: Voltage Above/Below Normal. This points directly to an electrical problem. The ECU is seeing a voltage reading that’s too high or too low in the ignition coil circuit for cylinder 1. This often means a short in the wiring or a failing ignition coil.
FMI 5: Current Below Normal / Open Circuit. This tells you there’s a break in the electrical connection somewhere. It could be a loose connector, a broken wire, or a completely dead ignition coil.
FMI 7: Mechanical System Not Responding. This is the one you hope you don’t see, but it’s still manageable. It suggests the issue isn’t electrical. The ECU is commanding the cylinder to fire, but its sensors aren’t seeing the expected result. This can point to a clogged fuel injector, low fuel pressure, or, in rarer cases, an internal engine issue like low compression.

The Most Common Culprits Behind a Misfire Code

Before you start tearing things apart, it helps to know the usual suspects. Over 90% of the time, code 65591 is caused by one of three things. This knowledge is one of the key benefits of a good 2017 rzr 1000 code 65591 polaris code diagnosis—it saves you from chasing ghosts.

Ignition System Woes

This is your prime suspect. The ignition system is responsible for creating the spark that ignites the fuel. It’s a high-wear system, especially in a machine that sees mud, water, and extreme vibration.

Fouled or Worn Spark Plug: The number one cause. It’s cheap, easy to replace, and should always be your first check.
Bad Spark Plug Wire or Cap: Cracks or corrosion can cause the spark to ground out before it reaches the plug.
Failing Ignition Coil: The coil transforms low voltage from your battery into the high voltage needed for a spark. When they fail, you get a weak or non-existent spark.

Fuel Delivery Problems

No fuel, no fire. If the spark is good, the next place to look is the fuel system.

Clogged or Faulty Fuel Injector: Ethanol in modern fuel can gum up injectors over time, preventing them from spraying the right amount of fuel.
Low Fuel Pressure: A weak fuel pump or a clogged fuel filter can starve the engine of the fuel it needs to run properly.

The Dreaded Wiring Gremlins

Your RZR’s wiring harness lives a tough life. Constant vibration and exposure to the elements can cause wires to chafe, break, or corrode, leading to intermittent electrical issues that are frustrating to track down.

Your Step-by-Step Guide: How to Diagnose 2017 RZR 1000 Code 65591

Alright, let’s get our hands dirty. This diagnostic process is designed to be methodical, starting with the easiest and most common fixes first. This is the core of our how to 2017 rzr 1000 code 65591 polaris code guide.

Safety First: Make sure your RZR is on level ground, in park, with the engine off and cool to the touch. It’s always a good idea to disconnect the negative battery terminal before working on electrical components.

Step 1: The Visual Inspection

Before you grab a single tool, use your eyes. Look around the cylinder 1 area (front cylinder). Check the spark plug wire. Is it securely seated on the plug and the coil? Do you see any cracks or burn marks? Follow the wiring harness from the coil and injector. Do you see any spots where it’s rubbing against the frame or engine block?

Step 2: The Ignition System “Swap Test”

This is the single most effective diagnostic trick in the DIY mechanic’s playbook. We are going to swap parts between the good cylinder (Cylinder 2, rear) and the bad one (Cylinder 1, front) to see if the problem follows the part.

Swap the Spark Plugs: Remove the spark plugs from both cylinders. Keep track of which is which! Install the plug from Cylinder 1 into Cylinder 2, and the plug from Cylinder 2 into Cylinder 1.
Clear the Code & Test: Reconnect your battery, start the RZR, and let it run for a minute. Does the misfire code now show up for Cylinder 2 (that’s code 65592)? If it does, you’ve found your problem: a bad spark plug. Easy fix!
Swap the Ignition Coils: If the code stayed on Cylinder 1, the plug is likely fine. Put the plugs back in their original spots. Now, do the exact same swap test with the two ignition coils. They are usually held on by a couple of small bolts. Swap them, clear the code, and re-test. If the misfire moves to Cylinder 2, you need a new ignition coil.

Step 3: Investigate the Fuel System

If the misfire is still on Cylinder 1 after the ignition swaps, it’s time to look at fuel. The most common fuel issue is a faulty injector.

You can perform a similar swap test with the fuel injectors, but it’s a bit more involved as you have to relieve fuel pressure and deal with gasoline. A simpler first step is to listen to the injector. With the engine running, take a long screwdriver, place the tip on the body of the injector, and press the handle to your ear. You should hear a distinct, rapid clicking sound. Compare the sound from Cylinder 1 to Cylinder 2. If Cylinder 1’s injector is silent or sounds lazy, it’s likely the culprit.

Step 4: Chase the Wiring

If you’ve ruled out the plug, coil, and injector, the problem is most likely in the wiring harness. This is where patience is key. Carefully inspect the wires leading to the coil and injector for Cylinder 1. Gently tug on the wires at the connectors to ensure they aren’t broken inside the insulation. Pay special attention to any area where the harness is zip-tied or rubs against a sharp edge.

Tools and Parts You’ll Need for the Job

Having the right tools makes all the difference. You don’t need a professional shop, just a few key items. This is a crucial part of any good 2017 rzr 1000 code 65591 polaris code guide.

Basic Socket Set: You’ll need 8mm and 10mm sockets for most of the work.
Spark Plug Socket: A dedicated 5/8″ deep well spark plug socket is essential.
Torque Wrench: Critical for tightening spark plugs to the correct spec to avoid engine damage.
Dielectric Grease: A must-have for any ignition work. It protects electrical connections from moisture and corrosion.
Replacement Parts: We recommend using high-quality OEM or trusted aftermarket parts like NGK spark plugs (the NGK CR9EKB is a common choice).

Best Practices for a Sustainable and Reliable Fix

Fixing it is one thing; making sure it *stays* fixed is another. A “sustainable” repair is one you only have to do once. Following these 2017 rzr 1000 code 65591 polaris code best practices ensures reliability.

When you install a new spark plug, always use a torque wrench. The spec for the RZR 1000 is typically around 10-12 ft-lbs. Over-tightening can damage the threads in the aluminum cylinder head, which is a very expensive mistake.

Apply a small dab of dielectric grease to the inside of the spark plug boot before reinstalling it. This prevents it from getting stuck on the plug and keeps moisture out, preventing future misfires. This simple step is a core part of any good 2017 rzr 1000 code 65591 polaris code care guide.

Finally, practice eco-friendly habits in your garage. Properly dispose of old spark plugs and any used parts. If you spill any fluids, clean them up thoroughly with an absorbent material and dispose of it according to your local regulations.

When to Wave the White Flag and Call a Pro

There is absolutely no shame in knowing your limits. If you’ve gone through the swap tests and inspected the wiring and you’re still stuck, it might be time to call for backup. This is especially true if you suspect an FMI 7 mechanical issue.

If a compression test is needed or if you’re facing a complex wiring problem that requires advanced diagnostic tools, a certified technician can save you time, money, and a lot of frustration. Don’t let a small problem become a big one by guessing.

Frequently Asked Questions About Polaris Code 65591

Can I still drive my RZR with code 65591?

It’s highly discouraged. When a cylinder is misfiring, unburnt fuel can be dumped into the exhaust system, potentially damaging the catalytic converter and oxygen sensor. Continued operation can also lead to cylinder washing, where fuel dilutes the oil, causing premature engine wear.

What is the most common cause of a misfire on a RZR 1000?

By far, the most common problems with 2017 rzr 1000 code 65591 polaris code are a bad spark plug or a failing ignition coil. Always start your diagnosis there.

How do I clear the check engine light after the repair?

Often, the code will clear itself after a few successful drive cycles where the ECU no longer detects the misfire. The quickest way is to disconnect the negative battery terminal for about 10-15 minutes, which will reset the ECU.

Does code 65591 always mean Cylinder 1?

Yes. The SPN (Suspect Parameter Number) 65591 is specifically assigned to the misfire detection circuit for Cylinder 1. A misfire on Cylinder 2 will trigger a different code, typically SPN 65592.

Tackling a check engine light can feel intimidating, but a misfire code like 65591 is the perfect opportunity to learn more about your machine and build your confidence as a DIY mechanic. By following a logical process—Inspect, Swap, and Verify—you can pinpoint the problem and get it fixed right.

Now you have the knowledge and the plan. Grab your tools, put on some tunes, and show that code who’s boss. Get it done, and get back on the trail where you belong. Ride safe!

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Thomas Corle

Founder & Automobile expert at FatBoysOffroad

Automobile expert and off-road enthusiast, sharing in-depth knowledge of vehicles, gear, and adventures. Helping readers make smart decisions and enjoy the thrill of off-roading safely and confidently.