Polaris Rzr Code 105 - Your Complete DIY Diagnostic & Fix Guide

You’re blasting down your favorite trail, kicking up dust, and grinning from ear to ear. Suddenly, that dreaded check engine light flashes on the dash, and your heart sinks. You scroll through the diagnostics and see it: polaris rzr code 105. It’s a frustrating moment that can cut a great day of riding short.

We’ve all been there. A cryptic code pops up, and you’re left wondering if it’s a minor hiccup or a trip-ending disaster.

But here’s the good news: you can absolutely handle this one. In this complete guide, we promise to demystify code 105, walking you through exactly what it means and how to diagnose and fix it right in your own garage. We’ll cover the symptoms, the tools you’ll need, step-by-step testing procedures, and how to get your RZR running perfectly again.

What Exactly is Polaris RZR Code 105? Decoding the Dash

When your RZR’s brain—the Engine Control Unit (ECU)—throws a code 105, it’s telling you there’s a problem with the Intake Air Temperature (IAT) sensor circuit. It’s not just a random number; it’s a specific signal that something is off with how your engine is breathing.

Think of the IAT sensor as your engine’s weatherman. Its only job is to measure the temperature of the air rushing into your engine. The ECU takes this information and uses it to make critical decisions, primarily adjusting the air-to-fuel ratio for peak performance.

Cold, dense air needs more fuel. Hot, thin air needs less. When the IAT sensor gives a faulty reading, the ECU gets confused and can’t create that perfect combustion cocktail. This is a crucial first step in understanding how to polaris rzr code 105 diagnostics work.

Breaking Down the Sub-Codes

Often, code 105 will be paired with another number, like a 3 or a 4. These are Fault Mode Identifiers (FMIs) and they give you a huge clue about the problem:

Code 105 3: This typically means “Voltage Too High” or “Open Circuit.” The ECU is seeing a voltage from the sensor that is higher than it should be, suggesting a broken wire or a disconnected plug.
Code 105 4: This usually indicates “Voltage Too Low” or “Shorted to Ground.” The ECU is seeing a voltage that is too low, often pointing to a wire that’s rubbed through and is touching the frame.

Symptoms and Common Problems with Polaris RZR Code 105

Your RZR will usually give you some performance clues that something is wrong, even before you see the code. A faulty IAT circuit can make your machine run poorly because the ECU is essentially guessing how much fuel to inject.

Here are the most common problems with polaris rzr code 105 that you might experience on the trail:

Check Engine Light: This is the most obvious sign.
Poor or Rough Idle: The engine may stumble or idle erratically.
Reduced Power: You’ll notice your RZR feels sluggish or hesitates when you hit the throttle.
Bad Fuel Economy: If the ECU thinks the air is cold (a common failure mode), it will dump in extra fuel, causing you to burn through your tank faster.
Hard Starting: The engine might struggle to fire up, especially when it’s very hot or cold outside.
Limp Mode: In some cases, the ECU will protect the engine by drastically limiting power and RPMs until the issue is fixed.

How to Diagnose Polaris RZR Code 105: Your Step-by-Step Guide

Alright, let’s get our hands dirty. This diagnostic process is straightforward and is the core of our polaris rzr code 105 guide. We’ll start with the simplest checks and work our way to the more technical tests. Don’t worry—you’ve got this.

Essential Tools for the Job

You won’t need a full professional workshop, but having a few key tools will make this job much easier. Gather these before you start:

A good Multimeter (this is non-negotiable for electrical diagnosis)
Basic socket and ratchet set
Torx bit set
Electrical contact cleaner
A pick or small screwdriver
Zip ties and electrical tape for tidy repairs
Pro Tip: Having your RZR’s service manual handy is always a good idea for wiring diagrams and torque specs.

Step 1: Visual Inspection (The Easiest First Step)

Before you grab any tools, use your eyes. The IAT sensor is typically located on the airbox or the intake boot between the air filter and the throttle body. It’s a small, two-wire sensor.

First, locate the sensor. Then, carefully inspect the area. Look for:

The Connector: Is it fully seated and clicked into place? Wiggle it gently. A loose connection is a very common culprit.
The Wiring: Follow the two wires coming from the sensor as far as you can. Are there any obvious signs of damage? Look for wires that are pinched, melted, frayed, or rubbed raw against the frame or engine components.
Corrosion: Unplug the sensor. Look at the metal pins inside both the sensor and the connector harness. Are they clean and shiny, or are they green and corroded from water and mud?

More often than not, you’ll find the problem right here. A quick spray of contact cleaner and ensuring a solid connection can sometimes be the only fix you need.

Step 2: Checking the Wiring and Connector

If the visual inspection doesn’t reveal anything, it’s time to break out the multimeter. We need to confirm the sensor is getting the power it needs from the ECU.

Turn your RZR’s key to the “ON” position (don’t start the engine).
Set your multimeter to DC Volts.
Carefully probe the two pins on the wiring harness connector (not the sensor itself). You may need to use the sharp points of your probes to touch the metal contacts inside the plastic housing.
You should see approximately 5 volts on one wire (the reference voltage from the ECU) and a good ground on the other. If you don’t see 5 volts, you have a wiring problem between the connector and the ECU.

Step 3: Testing the IAT Sensor Itself

If the wiring checks out, the sensor itself is the next suspect. An IAT sensor is a type of thermistor, which means its electrical resistance changes with temperature. We can test this easily.

Remove the IAT sensor from the intake. It’s usually held in by one or two small bolts or it may simply twist into place.
Set your multimeter to measure Resistance (Ohms, Ω).
Touch your multimeter probes to the two metal pins on the sensor.
Note the resistance reading at ambient air temperature. It should be somewhere in the range of 2,000-3,000 Ohms (2-3 kΩ), but check your service manual for the exact spec.
Now, gently warm the tip of the sensor with a hairdryer or heat gun on a low setting. Do not use a lighter or torch! As the sensor warms up, you should see the resistance reading smoothly decrease. If it jumps around erratically or doesn’t change, the sensor is bad.

This simple test is one of the best polaris rzr code 105 tips for confirming a failed part before you spend money on a new one.

Fixing the Root Cause: From Simple Repairs to Sensor Replacement

Once you’ve identified the culprit, the fix is usually pretty simple. Let’s walk through the solutions.

Repairing Damaged Wiring or Connectors

If you found a broken wire, you’ll need to repair it properly. For a clean break, use a quality butt connector with heat shrink to create a strong, weather-sealed connection. If the insulation is just rubbed through, you can often get away with a good wrap of high-quality electrical tape.

For corroded connectors, spray them liberally with electrical contact cleaner and use a small brush or pick to gently scrub the pins clean. Once dry, apply a small amount of dielectric grease to the connector before plugging it back in. This will prevent future moisture intrusion.

Replacing the IAT Sensor

If your tests confirmed a bad sensor, replacement is the only option. This is typically a very easy job.

Unplug the electrical connector.
Remove the bolt(s) holding the sensor in place.
Gently pull the old sensor out.
Apply a little grease to the O-ring of the new sensor to help it seal properly.
Install the new sensor, tighten the bolt(s), and plug the connector back in.

Clearing the Code and Test Driving

After performing your repair, you need to clear the code from the ECU. The easiest way is to disconnect the negative battery terminal for about 10 minutes. This will reset the ECU and clear any stored fault codes.

Reconnect the battery, start your RZR, and let it idle for a minute. The check engine light should be off. Take it for a short test drive to confirm that the code doesn’t return and that the performance issues are gone.

The Benefits of a Proper Polaris RZR Code 105 Fix

Taking the time to properly diagnose and fix this code offers significant rewards. The benefits of polaris rzr code 105 resolution go far beyond just turning off a light on your dash.

Restored Performance: Your engine will have the correct air-fuel mixture again, restoring lost power and throttle response.
Improved Fuel Economy: No more dumping excess fuel. You’ll get more miles and more fun out of every tank.
Engine Longevity: Running consistently too rich or too lean can cause long-term damage to spark plugs, O2 sensors, and internal engine components. A proper fix protects your investment.
Peace of Mind: There’s no better feeling than hitting the trail with a machine you know is running at 100%.

Best Practices for Prevention and Sustainable RZR Care

An ounce of prevention is worth a pound of cure. Following a few polaris rzr code 105 best practices can help you avoid seeing this code in the first place.

This is also where we can talk about a more sustainable and eco-friendly approach to ownership. A well-maintained machine lasts longer, requires fewer replacement parts, and runs cleaner. That’s a win for your wallet and the environment.

Regular Inspections: Every time you clean your air filter, take 30 seconds to inspect the IAT sensor and its wiring for any signs of wear or damage.
Use Dielectric Grease: If you ride in a lot of mud, water, or dust, applying dielectric grease to key electrical connectors like the IAT sensor is a cheap and effective way to prevent corrosion.
Secure Your Harness: Make sure the wiring harness is properly secured with zip ties and isn’t flopping around where it can get snagged on a branch or rub against the frame. This is a core part of any good polaris rzr code 105 care guide.

Frequently Asked Questions About Polaris RZR Code 105

Can I still ride my RZR with code 105?

You can, but it’s not a good idea for an extended period. Your machine will likely run poorly, use more fuel, and in some cases may be in a power-limiting limp mode. It’s best to diagnose and fix the issue as soon as possible to prevent potential long-term engine harm.

How much does it cost to fix code 105?

This varies greatly. If it’s a simple wiring fix you do yourself, the cost could be next to nothing. If you need to replace the IAT sensor, the part itself typically costs between $30 and $60. If you take it to a dealer or shop, you can expect to pay for an hour or two of labor on top of the part cost, likely in the $150-$250 range.

Where is the IAT sensor located on my RZR?

Its location can vary slightly by model and year, but it is almost always found on the clean-air side of the intake system. Look on the lid of your airbox or on the large rubber boot that connects the airbox to the engine’s throttle body. Consult your owner’s or service manual for the exact location on your specific RZR.

What’s the difference between code 105 3 and 105 4?

These sub-codes help you narrow down the search. Code 105 3 (Voltage Too High) often points to a disconnected plug or a broken wire, creating an open circuit. Code 105 4 (Voltage Too Low) usually means a wire’s insulation has worn through and is shorting to the metal frame (ground).

Tackling a check engine light can feel intimidating, but code 105 is one of the most DIY-friendly issues you can encounter. By following these steps—a visual check, a simple multimeter test, and a targeted repair—you can save yourself a trip to the dealer and gain valuable experience working on your own machine.

Now you have the knowledge and the confidence to solve this common problem. Get those tools out, get that RZR fixed, and get back to what matters most: enjoying the ride. Wrench on and stay safe out there!

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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.