Can-Am Defender Problems – Complete Troubleshooting Guide

Can-Am Defender Problems

If you own or are considering purchasing a Can-Am Defender utility side-by-side (UTV), you’ve likely wondered: what are the most common Can-Am Defender problems, and how can I diagnose and fix them?

While the Defender is a capable and well-engineered machine, it can develop issues just like any powersports vehicle. By learning to identify common problems and troubleshoot them yourself or seek professional help when needed, you can get your Defender back on the trails or work site.

In this complete troubleshooting guide, we’ll cover:

  • The most common Can-Am Defender problems owners face related to the engine, drivetrain, electrical system, and brakes
  • Likely causes and failure points that lead to these problems
  • Steps to diagnose Defender issues yourself
  • Methods to repair common problems and tips for preventative maintenance
  • Warning signs that signal when it’s time to take your Defender in for professional service

Let’s get started exploring why Defenders experience problems, how to get yours back up and running, and hit the road with confidence.

Common Can-Am Defender Problems

The Can-Am Defender is powered by a Rotax V-twin engine and uses a continuously variable transmission (CVT) to transfer power to the wheels. This powertrain combination delivers plenty of torque while the chassis and suspension soak up rough terrain.

However, like any machine, there are certain vulnerabilities and common problems owners can encounter. Here are some of the most frequently reported Can-Am Defender issues:

Engine Problems

The Defender’s Rotax engine provides responsive acceleration and ample power for traversing all sorts of terrain, hauling cargo, and powering attachments. However, engine problems can bring your Defender to a halt. Some common issues include:

  • Overheating – A blocked radiator, coolant leaks, faulty water pump, or broken fan can allow engines to overheat, potentially causing severe engine damage.
  • Loss of power – Fouled spark plugs, clogged air filters, leaky exhausts, or lack of proper fuel delivery can all sap engine power.
  • Excessive oil consumption – This points to internal leaks and worn piston rings or valve guide seals. Operating low on oil can lead to further engine damage.
  • Engine knock or ticking – Problems like low octane fuel, faulty ignition timing, or carbon buildup can cause detonation and engine knocking noises.

Drivetrain Issues

The CVT and gearcase play a key role transferring engine torque to the wheels. Some weak points include:

  • Grinding noises from the CVT – Debris entering the CVT housing or worn/loose belt components can cause unsettling grinding or whining noises, and lead to belt failure.
  • Belt slippage – Worn belt, low CVT fluid, or improper tuning can all cause the belt to lose traction and slip during acceleration.
  • Gear selection problems – Damaged shift forks, worn gears, or blocked fluid passages prevent smooth gear engagement in the transmission and differential.

Electrical Problems

Like most vehicles, Defenders incorporate complex wiring harnesses, control modules, sensors, and switches to operate lighting, gauges, power accessories, and more. Some electrical gremlins owners encounter are:

  • Battery not holding a charge – Old batteries eventually lose their ability to hold a full charge. Loose terminal connections or a faulty stator charging system can also cause charging issues.
  • Lights and accessories not working – Blown fuses, damaged connectors, corrosion, or short circuits can knock out lighting and accessories powered through the Defender’s electrical system.
  • Issues with gauge and dashboard readings – Sensors and ECUs monitoring systems like engine RPM, temperature, and fuel level can fail and display incorrect readings.

Braking Problems

Reliable braking ability is critical for controlling your Defender, especially when hauling and descending steep hills. Look out for:

  • Soft or spongy brake pedal – Air in the brake lines or leaking fluid causes a loss of pedal pressure and firmness.
  • Brakes grabbing or pulsating – This indicates warped brake rotors that need resurfacing or replacement.
  • Reduced braking power – Pads wearing down to the limit, brake fluid leaks, or mechanical issues like a stuck caliper piston can greatly reduce braking force.

What Causes These Issues?

Now that we’ve spotlighted some of the most common problems reported by Can-Am Defender owners, what actually causes these failures and malfunctions? Here are the typical culprits behind Defender issues:

Engine Problems

Under the hood is where most problems originate. Some things that commonly lead to Defender engine troubles are:

  • Clogged air intake system – A blocked air filter or debris in the airbox restricts airflow into the engine, resulting in decreased power.
  • Fouled or worn spark plugs – Carbon deposits or wear on the electrodes disrupt the spark, hurting ignition timing and combustion efficiency.
  • Low oil level – Insufficient oil causes increased friction and wear inside the engine, which can lead to overheating and reduced power.
  • Exhaust leaks – Small leaks in the exhaust like a blown gasket allow hot gases to escape and disrupt proper cylinder pressure and combustion.

Drivetrain Issues

The CVT and transmission take a beating on rough trails and when hauling heavy cargo. Some weak points are:

  • Worn or loose CVT belt – A worn belt loses grip, slips on the pulleys, and can shred apart. Low belt tension also reduces traction.
  • Debris built up in the CVT – Mud, rocks, and other debris can become packed in the CVT housing, wearing the belt and clogging components.
  • Low fluid levels – The CVT and gearcase require regular fluid changes. Low levels cause increased wear and turbulence.
  • Damaged gears – Broken gears or weakened shifting forks prevent smooth drivetrain operation.

Electrical Gremlins

Defender’s electrical systems can fall prey to:

  • Faulty battery – Vibration, corrosion, age, and improper maintenance shorten battery life. A weak battery affects starting and the charging system.
  • Loose or damaged wiring – Vibration slowly loosens connectors and frays wiring insulation over time, leading to shorts and cut-outs.
  • Blown fuse – Overloads from short circuits or incorrect accessory installations can blow fuses and disable affected systems.
  • Sensor malfunction – Defective sensors like the coolant temperature sensor or throttle position sensor relay bad readings to the ECU.

Braking Problems

Your brakes take heavy abuse on off-road terrain. Some factors that impair braking are:

  • Worn brake pads/rotors – Constant use eventually wears away pads and rotors until they lose stopping power and need replacement.
  • Air in brake lines – Air bubbles compress rather than transmit full braking hydraulic pressure.
  • Leaking brake fluid – Leaks result in lower fluid levels and allow air into the system.
  • Sticking brake caliper – Corrosion and debris cause caliper pistons to stick and prevent full pad contact with the rotor.

How to Diagnose and Fix Defender Problems?

When your Defender suffers issues ranging from lack of power to intermittent electrical gremlins, there are ways you can begin to diagnose problems before resorting to a mechanic. Here are some helpful troubleshooting steps:

Check Error Codes

Many Defender problems trigger diagnostic trouble codes (DTCs) that are stored in the Electronic Control Module (ECM). Connecting a handheld scan tool lets you read these codes. The code indicates the sensor or system that has failed or is out of spec. Checking codes first points you where to start investigating.

Test Components

Some common tests you can perform to further diagnose problems are:

  • Battery load test – Use a voltmeter or load tester to check the battery’s charge level and health.
  • Test spark plug ignition – Remove the plugs and check for correct gap. Connect to ignition coils to see if they are firing properly.
  • Pressure test the cooling system – Use a pressure tester on the radiator cap to check for leaks and confirm system integrity, especially if overheating.

Thorough Inspections

Closely inspecting the Defender helps spot leaks, damage, and wear:

  • Inspect belts, hoses, wiring – Look for cracked hoses, damaged wire insulation, leaks near gaskets and water pump seals.
  • Check for debris buildup – Look inside the CVT housing and intakes for compacted mud or vegetation that could cause blockages.
  • Assess corrosion and wear – Check battery terminals, exhaust components, drivetrain, and frame for rust and excessive wear.

Follow Maintenance Schedule

Many problems are avoided by diligent maintenance of:

  • Fluid changes – Replace engine oil, transmission oil, brake fluid, and coolant per factory intervals.
  • Filter replacements– Swap out air, oil, and fuel filters when specified.
  • Spark plugs – Old plugs have worn electrodes. Install a fresh set around 100 hours of use.

Preventative steps like greasing fittings, checking torque specs, washing mud and dust off, and assessing tire condition also helps minimize problems.

Warning Signs to Seek Professional Help

While you can diagnose and fix some issues yourself, there are a few warning signs that indicate it’s time to take your Defender into a professional mechanic:

  • Repeated overheating – Chronic overheating usually points to internal engine problems best assessed by a pro. Driving while overheated can warp cylinder heads.
  • Major loss of power – A sudden and severe power loss when accelerating signals a major mechanical or fuel delivery problem that needs a shop to troubleshoot.
  • Brake failure – Problems like total brake fade or a pedal going to the floor require the skills of an experienced mechanic to safely resolve. Don’t drive the Defender.
  • Critical electrical failure – Issues like a dead battery combined with no lights, fuel pump not turning on, or no response from the starter all render the Defender undriveable. Seek professional help.

Seeking timely professional service when you encounter these serious issues can often resolve them before small problems cascade into very costly repairs.


Like any machine, Can-Am’s Defender UTV is susceptible to issues such as overheating, loss of power, electrical gremlins, and braking problems. However, being able to identify common Defender problems and pinpoint their root causes helps you get back on the trail faster.

Follow basic troubleshooting steps like checking error codes, testing components, inspecting systems, and performing preventative maintenance. Seek out professional service for severe issues. Keeping up with regular service, following your Defender’s maintenance schedule, and addressing problems promptly reduces long-term repair costs.

With vigilance and care for your Defender, you can continue to enjoy the capabilities and adventures provided by this rugged and dependable side-by-side for years to come. Our troubleshooting guide helps you diagnose issues, handle basic repairs yourself, and know when it’s time to visit a professional. Use the tips provided to keep your Can-Am Defender running strong.

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