Understanding Your ATV’s Check Engine Light & The Seriousness Of It

The purpose of a check engine light for your ATV or side by side is to warn you of problems or future problems with your machine.

The light is so broad that it’s often hard to say it’s one thing. Sometimes, the display will let you know more, while others require the machine to be brought to the dealer to read the error codes.

You should not ignore this light, even if your machine runs fine. For many ATVs and side by sides, this light will put you in a limp home mode, as covered in this post.

Things That Trigger Check Engine Lights

I’ve listed most reasons below for your reference. However, if I’m being honest, understanding the exact cause often means taking a trip to your local dealer to have the codes read. And, frustratingly, not every dealership offers this service without a fee. Always irks me a bit that we have to pay for that, especially if you’re going need to buy something anyway.

  1. Battery or Charging System Issues: A bad battery or problems with the charging system can trigger the light. You’ll be amazed by how many warning lights are simply a weak or bad battery. Charge your battery or even replace it, do a load test to make sure it’s good. Even loose battery connections can cause it.
  2. Dirty Sensors: If you ride in the mud, a lot of mud can find its way to all kinds of places and cause issues with sensors. Try giving your machine a good cleaning to see if it helps remove the light and look in places where mud might have gotten.
  3. Bad Gas: Fuel injected models these days are more picky about their gasoline, so if the gas is old or bad, it will throw a fit. If you have a machine with a turbo, you need to run premium, or it will throw a warning light.
  4. Bad Fuel Pump: A bad fuel pump can turn on the light. You should hear the fuel pump run for a second when you first turn them on.
  5. Loose or Faulty Gas Cap: A loose or damaged gas cap can cause fuel vapors to leak out and can result in reduced fuel efficiency and increased emissions.
  6. Mass Airflow Sensor (MAF) Failure: This sensor measures the amount of air entering the engine and determines how much fuel is needed to run the engine efficiently. A malfunctioning MAF can cause a variety of issues, including stalling or reduced performance.
  7. Spark Plug or Ignition Coil Problems: Faulty spark plugs or a malfunctioning ignition coil can affect the unit and cause a light.
  8. Fuel Injector Issues: Clogged or malfunctioning fuel injectors can cause the engine to misfire, which leads to a warning light.
  9. Vacuum Leak: If there’s a break in the vacuum system, it can throw a light.
  10. Transmission Problems: Some models may light it if there are issues with the transmission. I’ve seen this many times when it’s stuck between gears or the gear selector sensor thinks you’re in one gear, but the transmission says something else.
  11. Throttle Position Sensor Malfunction: This sensor measures the throttle’s position, which controls how fast you go. Sometimes the sensor needs to be reset if you make major changes to the engine or transmission, but you often need the dealer software to reset it.
  12. Coolant Temperature Sensor Issues: An overheating engine can throw the light, and it’s mostly from mud being stuck on the radiator fans or places it shouldn’t be.
  13. Software or Firmware Glitches: Modern 4-wheelers have computers, and they need to be updated at the dealership. There is also the possibility that a dealership did not program your new machine right, as they all have a warning light when coming out the box and must be hooked up and reset properly.
  14. Foreign Debris or Water Ingestion: If you go in the mud, be careful to not get water in the engine. Water in the engine can destroy it, and definitely throw a light.
  15. Loose Wire Or Fuse: Modern 4-wheelers have many electrical things, this means wires can come loose and fuses can blow. You’ll be amazed by how many I’ve fixed because a wire had come loose from its connector or a fuse was blown.

Reading The Check Engine Light

Most displays will show you the fault code along with lighting up the warning light.

Some require you to hold down the MODE button for a few minutes and scroll to see the fault codes. Others have it hidden in the settings options of the display. You even have some that will you the P0 CODE when you first turn it on.

Do This First

When you see the light going off, it’s best to turn it off.

Then turn it back on to see if a P0 code shows up, or scroll through the settings to see if there is a fault code.

Once you have the fault code, check your owner’s manual on what to do or call your local dealership. Sometimes a simple Google search of your fault code works the best.

When you know what the code means, you can start fixing.

How To Reset Your Own Lights

Based on my experience, it can be both surprising and slightly frustrating to see the light remain on, even if you’re confident the issue has been resolved. Often, the computer maintains this light in an active state, effectively “remembering” the problem, so that a repair shop can access the stored code.

Now, here’s a bit that genuinely baffles me: not all machines allow the owner the simple liberty to reset their own warning light. It feels backwards, doesn’t it? Fortunately, some do have this capability, which I think should be standard across the board.

Try these steps below to reset it:

  • Hold down the “Mode” or “Set” button.
  • With the power on, but the engine off, scroll to settings using the mode button and look for the reset option.
  • Turn on, keep the engine off, hold down the override button for 30 seconds. The override button is on the left side of the handlebars and often yellow, it allows you to go faster in reverse or cycle settings like power steering.
  • Turn on and off, don’t start it, at least 5 times.
  • Disconnect the battery for 15 minutes.
  • Ride, if you know you fixed it, sometimes it just needs a few minutes of running around to reset.
  • Take it to the dealership to hook it up and clear the code, may have a fee.

You can buy scan tools, but they’re rarer and going to the dealership is often the best route. If you’re curious, you can get a Can-Am ATV scan tool here (ad).