​Polaris RZR Sensors: Why Do You Need Them And How To Replace Them

You might not know it, but there’s a whole lot going on in the “brain” of your side-by-side at any given moment. Using numerous monitoring devices such as Polaris RZR speed sensors, Polaris RZR O2 sensors, and Polaris RZR temp sensors, your machine’s electronic control unit (ECU) is able to get the real-time data it requires to synchronize and optimize the various systems and subsystems that co-exist within the vehicle. The RZR Turbo, for example, has three different manifold absolute pressure (MAP) sensors to maintain the appropriate PSI so that an optimal air-to-fuel ratio can be achieved. Other sensors such as Polaris RZR brake sensors and Polaris RZR TPS sensors play a crucial role as well, so it’s important to have accurate and fully-functional Polaris RZR sensors working their magic in your buggy! And with that, here are some of the most common Polaris RZR sensor issues as well as how to diagnose and rectify them!

Polaris RZR Speed Sensors

Polaris RZR speed sensors are tricky, and as you might expect with complex systems, there are myriad things that can cause a speed sensor error code to be thrown. Unlike the old-school automotive speedometers which use springs and magnets to track the vehicle's speed, new-age speed sensors look at the rotational speed of the gears within the Razor's transmission. This information is sent to the ECU, and the ECU then computes the ground speed you're traveling at and displays that number on the dash.

Speed sensor error codes can be thrown for a variety of reasons. Sometimes it’s intermittent, illuminating randomly, then turning off and appearing completely normal again. If you’re getting on-again off-again speed sensor errors with misfire codes from time to time, check the orange speed sensor wire for damage – especially where it is zip-tied to the front motor mount.

In some instances, you’ll need a full speed sensor replacement. But once it's installed, the error code should clear itself – but it might come back every time you start your machine and then clear shortly thereafter. If the speed sensor is faulty, it’ll be covered under warranty; so at least there’s that!

Brake Switches And Polaris RZR Brake Sensors

The Polaris RZR and RZR 4 are both notorious for brake pressure switch and brake sensor issues. And because the brake sensor works almost like an inline fuse before the speed sensor, it can cause the latter to lose all connection when the former goes out. You’ll know if your brake switch is bad because the brake lights will come on by themselves, and you’ll get a code which indicates that the machine thinks you’re “2 footing it”, with one foot on the gas and the other on the brake. Water will often ruin both brake sensors as well as speed sensors, so ensuring that you get a quality option like the Hall Effect speed sensor by Quad Logic is smart! Dielectric grease can also help waterproof your sensors so that they don't get damaged while washing or creek crossing.

Polaris RZR Crank Position Sensors

To clear the crank position sensor code when it pops up, changing the sensor is often the cure. If not, the wiring is the next thing to inspect. If the code still persists, you’ll want to check normal things like the fuel and the timing. On some Razors, the trigger wheels can break away and spin freely on the crank, while in others, a broken keyway on the mag side is the culprit. You can pull the mag plate block halfway off to inspect things, and if no visible damage is noted, you can then ohm out each wire in the vicinity. You can also check for 5V reference signals / circuits on each wire as well to know if the right amount of power is flowing through.

Polaris RZR Gear Position Sensors

Another sensor that needs to be replaced when it acts up is the gear position sensor. In some instances, it’ll put the vehicle into limp mode without throwing any lights or error codes at all. In other instances, a gear icon will appear on the dash randomly, then disappear like nothing happened. A bad Polaris RZR gear position sensor can also cause the dash to flash like the vehicle is in reverse, and if you swap belts, it might fix the issue for a few hours or so. The the factory trans and motor alignment on 2019 Razors is particularly bad, so an alignment might be in order. Otherwise, make sure to check the wires and connectors on the sensor to ensure that it’s clean and connected.

Polaris RZR MAP Sensors And TMAP Sensors

Both MAP sensors and TMAP sensors are crucial so that you don’t overload or over-pressurize the motor. TMAP sensors, however, have an additional temperature sensor as well so that the ECU can better calculate the air density within the engine manifold. Add a turbo to the mix and you’ll need even more sensors to control the interplay between the engine, the turbocharger, and the intercooler.

The off-road firm Quad Logic is a popular company that makes aftermarket Polaris RZR TMAP sensors. Each machine is different, but because Quad Logic makes TMAP sensors for the Polaris RZR 800, the RZR 570, the RZR Turbo, and all other Razor editions, they're sure to have the precise sensor for you and your rig!

Polaris RZR Knock Sensors

The error code for the knock sensor in the Polaris RZR is 520332/4, and like with other sensor issues, the first thing you should do when a knock sensor error code is thrown is check the wiring for obvious nicks -- and give it a light pull / wiggle at the connection point. Also, be sure to ohm the connector to check for continuity, and make sure that the knock sensor wires inside the harness are still good – years of vibration can do a number on those and other wires!

Polaris RZR O2 Sensors And O2 Sensor Deletes

In conjunction with the MAP sensor, the Polaris RZR O2 sensor helps to regulate the vehicle’s air-to-fuel mixture so that it doesn’t run too fuel rich or too fuel lean. Error code 520344 can sometimes mean your O2 sensor is bad, but it could also indicate problems with the fuel pump or TMAP sensor.

The O2 sensor in the Polaris RZR is located right before the muffler on the header side of the factory exhaust. But riders who’ve installed aftermarket exhausts sometimes perform a Polaris RZR O2 sensor delete – which will require an ECU tuner or something similar to tell the computer that it shouldn't look for that information anymore.

Closing Notes

Be it a Polaris RZR thermistor sensor to keep temperatures within a specific window, or a Polaris RZR TPS sensor to control the position of the throttle valve, the sensors inside your rig play a vital role, and without them, your rig would simply cease to function. Replacement sensors like the ones from Everything Polaris RZR are often the correct course of action, but before you pop on one, make sure that the sensor wires and sensor wiring harnesses aren’t damaged, nicked, cut, loose, or corroded. And if you still can’t clear those error codes, perhaps an ECU flash / reflash is in order!