You’re geared up for a day on the trails. You turn the key, and instead of a healthy roar, your Polaris sputters to life, running rough and shaking like a wet dog. The check engine light starts flashing, and a quick check of the diagnostics reveals the dreaded polaris code 746 5. Your day is suddenly on hold.
I’ve been there, and that frustration is real. But before you throw in the towel and book a costly appointment at the dealership, I’ve got good news. This is one of the most common codes on these machines, and it’s often something you can diagnose and fix right in your own garage.
We promise this guide will give you the confidence and the step-by-step instructions to tackle this problem head-on. We’ll break down what the code means in plain English, show you the most common culprits, and walk you through the entire troubleshooting process. Let’s get your machine running right and get you back out there.
What Exactly is Polaris Code 746 5? (Decoding the Jargon)
Seeing a string of numbers on your dash can be intimidating, but it’s just your machine’s way of talking to you. Think of it as a specific pointer telling you where to start looking. This particular code is a combination of two numbers.
The first part, SPN 746, stands for Suspect Parameter Number. This number points to the Injector 1 Circuit. On most twin-cylinder Polaris models like RZRs and Rangers, “Injector 1” is the one on the PTO (Power Take-Off) side of the engine—that’s the same side as your clutches, which is typically the rear cylinder.
The second part, FMI 5, is the Failure Mode Identifier. This number tells you the specific problem the ECU (Engine Control Unit) has detected. In this case, it means “Current Below Normal / Open Circuit.”
Putting it all together, polaris code 746 5 means: “The engine’s computer has detected an open or grounded electrical circuit for the rear fuel injector.”
In simple terms, the electrical signal that’s supposed to be firing the rear injector isn’t making it. This forces your powerful twin-cylinder engine to run on only one cylinder, leading to some very obvious symptoms.
Common Symptoms You’ll Notice
- A very rough idle and excessive engine vibration.
- Significant loss of power; the machine will feel sluggish.
- The engine may backfire or pop, especially on deceleration.
- A flashing Check Engine Light (CEL).
- Difficulty starting the engine.
The Common Culprits: What Causes Code 746 5?
While it sounds complex, this code is almost always caused by a handful of simple, common problems. Off-roading involves a ton of vibration, heat, and exposure to mud and water, which is tough on electrical systems. Here are the most likely suspects, from most to least common.
Damaged Wiring Harness
This is, without a doubt, the number one cause. The thin wires running to the fuel injector are vulnerable. Over time, engine vibration can cause the harness to rub against the frame, a sharp edge on the engine block, or the heat shield.
Eventually, the insulation wears through, causing a wire to break (an open circuit) or touch the metal frame (a short to ground). Check the harness carefully where it runs behind the clutch cover and near the exhaust manifold.
A Bad Fuel Injector Connection
The plastic connector that plugs onto the fuel injector itself can also be the source of your headache. It can become filled with dirt or water, causing corrosion on the electrical pins.
It’s also possible for the connector to simply vibrate loose over time, creating a poor connection that the ECU interprets as an open circuit. This is one of the first and easiest things to check.
A Failed Fuel Injector
While less common than wiring issues, the fuel injector itself can fail internally. The tiny electronic coil inside the injector can break, creating an open circuit. You can easily test for this with a simple tool, which we’ll cover in our diagnostic guide below.
ECU Issues (The Rarest Cause)
This is the one nobody wants, but thankfully, it’s extremely rare. It is possible for the driver circuit inside the ECU to fail. However, you should exhaust every other possibility before even considering the ECU is the problem. In 99% of cases, the issue is with the wiring or the injector.
Your Toolkit for Tackling Polaris Code 746 5
You don’t need a full professional shop to handle this job. A few basic tools will get you through the entire diagnostic and repair process. Having these ready will make everything go smoothly.
- Basic Hand Tools: A good socket and ratchet set, along with a set of Torx bits, will be necessary to remove any body panels or heat shields to access the engine.
- Digital Multimeter (DMM): This is your most important tool for this job. You simply cannot properly diagnose an electrical fault without one. Even an inexpensive model will work perfectly for testing continuity and resistance.
- Injector “Noid” Light: This is an optional but very helpful little tool. It plugs directly into the injector harness and flashes to confirm if the ECU is sending a firing signal.
- Electrical Repair Supplies: Have some quality electrical tape, zip ties, and heat-shrink tubing on hand. If you find a broken wire, you’ll want to repair it correctly.
- Contact Cleaner & Dielectric Grease: Essential for cleaning dirty connectors and protecting them from future corrosion.
How to Polaris Code 746 5: A Step-by-Step Diagnostic Guide
Alright, let’s get our hands dirty. Follow this polaris code 746 5 guide step-by-step. Don’t skip ahead, as a methodical approach is the fastest way to find the root cause.
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Safety First!
Before you do anything, park the machine on a level surface, turn it off, and remove the key. Let the engine cool down completely, especially the exhaust. As a final precaution, disconnect the negative terminal on your battery to prevent any accidental shorts.
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The All-Important Visual Inspection
Your eyes are your best first tool. Locate the rear fuel injector (the one on the clutch side). Start at the injector’s plug and slowly trace its wiring harness back as far as you can see.
Look for any signs of trouble: wires that look pinched, melted spots from touching the exhaust, or areas where the plastic loom is worn through and bare wires are exposed. Pay close attention to any point where the harness is attached to the frame with a zip tie.
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Check the Injector Connector
Carefully unplug the electrical connector from the rear fuel injector. You may need to press a small tab to release it. Inspect both the harness side and the injector side. Are the metal pins clean and straight? Is there any green or white crusty corrosion? Is there any sign of dirt or moisture inside? If it looks dirty, give it a good spray with electrical contact cleaner and let it dry completely.
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Test the Wiring with Your Multimeter
This is where we confirm if the wiring is good or bad. Set your DMM to the continuity setting (it usually has a symbol that looks like a sound wave). It will beep when you touch the two probes together.
Checking for an Open Circuit (Broken Wire)
You need to test the two wires that run from the injector plug back to the main ECU plug. This can be tricky, so you may need to find a wiring diagram for your specific model. Unplug the large connector at the ECU. Probe one of the pins in the injector plug, and then find the corresponding pin on the ECU plug. If the multimeter beeps, that wire is good. If it stays silent, you’ve found your broken wire. Test the second wire the same way.
Checking for a Short to Ground
Keep the harness unplugged from the injector and ECU. Set your DMM to continuity again. Touch one probe to a pin on the injector plug and the other probe to a clean, unpainted metal part of the chassis or engine block. The multimeter should remain silent. If it beeps, that wire is shorted to ground somewhere. Test the other wire the same way.
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Test the Fuel Injector Itself
If the wiring checks out perfectly, the injector itself might be the problem. Switch your DMM to the resistance setting, marked with the ohm symbol (Ω). Touch one probe to each of the two metal prongs on the fuel injector itself.
You should see a reading, typically between 12 and 15 ohms (check your service manual for the exact spec). If you get a reading of “OL” (Open Line) or 0.0, the injector’s internal coil is broken, and the injector needs to be replaced.
Repairing the Problem: Best Practices for a Lasting Fix
Finding the problem is half the battle. Fixing it correctly ensures you won’t be dealing with it again a few weeks down the road. This is where you can apply some polaris code 746 5 best practices for a truly sustainable repair.
Fixing a Broken Wire Properly
If you found a broken or chafed wire, don’t just twist it together and wrap it in tape. That’s a temporary fix at best. For a permanent, weather-proof repair, carefully strip both ends of the broken wire, slide a piece of heat-shrink tubing over one side, solder the wires together, and then slide the heat-shrink over the joint and warm it with a heat gun to seal it.
Protecting the Harness for the Future
Once repaired, prevent the problem from reoccurring. Wrap the vulnerable section of the harness in a protective wire loom or a high-temp sleeve if it’s near the exhaust. When re-securing it, use new zip ties but leave them slightly loose. Overtightening zip ties can cut into wires over time. This is a key part of any good polaris code 746 5 care guide.
Replacing the Fuel Injector
If your injector tested bad, replacement is straightforward. Be sure to relieve any pressure in the fuel system first. Then, unbolt the fuel rail, carefully pull it back, and the injector will pop out. When installing the new one, lightly lubricate the new O-rings with a little motor oil to ensure they seat properly and don’t get torn.
Frequently Asked Questions About Polaris Code 746 5
Can I still ride my Polaris with code 746 5?
It’s highly recommended that you don’t. While the machine might run, you’re essentially dumping raw, unburned fuel into one cylinder and the exhaust. This can wash oil from the cylinder walls, cause engine damage, and potentially damage your catalytic converter over time. It’s okay to limp it back to the truck or garage, but avoid any extended riding.
My wiring and injector both tested good, but the code is still there. What’s next?
Go back and double-check your work. Electrical gremlins can be tricky. Ensure the injector plug is seated firmly and that your wire repair is solid. If you are 100% certain the entire circuit from the ECU to the injector is perfect, only then should you begin to suspect an issue with the ECU itself, which may require a trip to the dealer for diagnosis.
Is this the same as Polaris code 747 5?
It’s the identical type of fault, just for the other cylinder. Code 747 points to Injector 2, which is on the MAG (magneto) side of the engine, typically the front cylinder. The diagnostic steps are exactly the same, just focused on the front injector’s wiring and connector.
By understanding what polaris code 746 5 is telling you, you’ve already won half the battle. This isn’t some mysterious, catastrophic failure. It’s a common electrical issue that, with a little patience and a methodical approach, you can absolutely conquer yourself.
Take your time with the visual inspection and be precise with your multimeter tests. The satisfaction of finding that one broken wire and fixing it for a few cents is far better than a thousand-dollar repair bill. Now grab your tools, get to work, and we’ll see you back on the trail!
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