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Troubleshooting RC Cars (The Things You Need to Look Out For)

Troubleshooting your RC car can be tough, so I am going to explain common issues you need to look out for, and how to fix them. The idea is to sae you money and time. Read on for more info.

What are the main things that can go wrong with your RC Car? Simple things are usually the problems in an RC car. Stuff like on/off switches, batteries, fuel, transmitter, and frequencies, antennas, servos, wiring, gears or a broken steering arms can go wrong, but they can also be fixed.

It’s also a great idea to join an RC car club so you can take advantage of their expertise in repairing and troubleshooting RC vehicles. Keep the box and instructions to the car.

These instructions can show you how to troubleshoot your RC car. Have the address of where you can return the car. Returning your RC car might be a last-ditch solution, but if you need to return your car for repairs, you do need the proper address.

In this article you I will explain how you can troubleshoot the most common issues to help saving you some time, money and headache.

Troubleshooting your RC Vehicle

Things can go wrong with an RC vehicle, even if you choose the best RC car from batteries to radio interference. If you know the batteries in the vehicle are good, and you have turned on the on switches and nothing happens, there are a few things you can check and repair yourself.

Check out the basics even if you did so a few days ago. Look at the antennas and make sure your vehicle is on the right frequency. If everything checks out, then you might need to go a little deeper into the problem.

If you hear a noise when your RC is running, and the sound is a crunching or grinding noise when using the throttle, you might have a slipped pinon gear. You can replace gears if they are stripped or re-mesh them. Order replacement parts from the company or visit your local hobby store.

If there is no noise when trying to steer your car, you may have a loose wire. Trace the wires that come out of the motor and look for broken wires or loose connections. If nothing works, it is possible you have a bad motor that needs replacing.


Look at the on and off switches. It could be embarrassing to find that the problem your RC car is not running, is because the RC car and the transmitter is turned off. You might notice on some RC cars you must use a flashlight to check if the switch is on or off.

Don’t be embarrassed; this is a common problem. Check the switches first and turn the switch on. If this doesn’t work, you may need to check out the switch itself.  Make sure your RC car switch is turned off before you work inside your car.


Batteries are a common problem. Battery problems can be the reason your RC car is running sluggish or doesn’t run. For batteries not charging, in electric, nitro or other RC cars, your batteries are most likely defective and will need to be replaced. There are also several things you can do to troubleshoot this problem before you go out and purchase new batteries.

  • Absent batteries: Look at both the RC car and the transmitter to make sure all the correct batteries are installed. Even one missing battery could cause you RC car to be erratic.
  • Wrong position: Batteries have distinct slots and need to face the right direction. Check the seating, the direction, and make sure the batteries are not worn out.
  • Old batteries: You might try new batteries. If you are using an inexpensive type of batteries use using another brand. If you use a battery pack in your RC car, take it out to ensure it is ready for use.
  • After Storage: If you haven’t used your RC car quite some time or changed the batteries, or even if the section has been uncovered and dirt or moisture get in, batteries might be corroded. Replace the batteries and clean the battery links.


Make sure fuel is not old and dirty. If you have an RC car that uses nitro, it can be very finicky. Don’t work on the engine before you first examine your fuel reservoir. Is the fuel fresh or do you even have fuel? Check for kinks that could happen in the tube that transfers the fuel. Check the entire fuel system. It does take time, but it is easy to check for kinks and loose connections.

You can also check the glow plug to make sure it is working. Take out the plug and put igniter on it. It should turn a bright orange. You can also check for low and high-speed idle screw settings and reset them. You can also take it to a dealer to discover what you are doing wrong.


Look at your antennas. Your RC car may have an antenna that telescopes on the RC car or the transmitter. Make sure it is fully extended. Sometimes, an antenna that is no fully extended keeps your car from running correctly. A lowered antenna could limit your range or cause the vehicle to run erratically.

Check the receiver antenna on your car to make sure it is properly installed. Check for twists or broken parts. You also need to make sure it is touching metal parts inside the vehicle and not dragging on the ground.

Transmitter and Frequencies

Are your transmitter and frequencies aligned?  Do you own several RC cars in your collection?  You might mix up the transmitters or have unaligned frequencies. Make sure you are using the right transmitter.

Purchasing your RC vehicle from someone else may give you transmitter problems. For example, you may have a transmitter that doesn’t go to your RC car.  Check the frequency sticker on the RC car it’s usually on the car’s bottom – maybe near the batter compartment or around the on and off adjustment.)

Your RC car and transmitter should have the same frequencies. If a transmitter doesn’t match the car, you may need to purchase the correct transmitter.

Are you driving around a hobby-grade RC car? Make sure the crystals in the transmitter and receiver match. If they don’t match you might need to switch them out.


Manage your servos. Servos are electronic devices used to operate RC cars, electronic toys, and electrical appliances. They determine the motion directions.

To put it simply, a servo contains a DC motor, circuit, gear train, output shaft, and potentiometer. They function based on the waves of pulses send by a command from a transmitter. These pulses create mechanical motion.

An example of a servo in an RC car is the mechanism used to adjust the levers back and forth and control the speed of a radio control car by connecting it to the engine throttle.

Signs that the problem is in the servos is if the RC vehicle doesn’t respond to all the orders coming out of the transmitter. Your wheels might turn, but your car won’t go forward.

Unplug the servos and replug them to another receiver that is running. Match the frequencies. If your car still doesn’t respond, then you may need to replace or repair your servos.

Shaking servos may mean low battery power. If your servos drop below 4.8 volts, you will need to change the batteries. Use rechargeable batteries if you have problems with shaking servos.

Changing the servos could be a tricky job. If you don’t feel comfortable working on insides of your RC vehicle, take your Remote Control car to the place you purchased your RC car. Your local RC club could also help you out.

Steering Servos

Steering servos are important. If your steering is not working, you can unplug the steering servo and the throttle servo from the receiver. Try switching their plug positions and check if they have exchanged functions – this can happen.

You will need to identify if the problem is the steering servo or the steering assembly. Make sure the steering is not too stiff. You can disconnect the steering from the steering servo by removing one screw that holds the horn and check if you can move the steering by hand.

There can be steering problems on your RC car. Most of the time it is your steering servo for servomechanism. You steering servo tells your RC car just about everything. If your steering quality is off, you may need to ensure you have the right servo and servo horn.

  • Make sure the servo horn is installed perpendicularly. Check for the right size and strength servo for you the way you use your RC car. You can replace the parts very simple by ordering the parts and screwing them in.
  • Check to see that all links in the car kit connect the servo to the steering rack and the rack to the wheels. Even if the radio and servo are communicating property, your car won’t go if the connections are not aligned.
  • Check the endpoints to make sure the adjustment is set correctly.
  • Your radio and servo need to have good connections. Make sure the servo transmitter is working by switching the servo and throttle connectors. If the controls on your radio work, you know everything’s okay.
  • If the throttle works, but not the steering, check to make sure the servo gears are not stripped, the wires are not frayed, the connector is not loose, and all links are correctly connected.


Wiring is essential; check it out. Broken or loose wires can cause many problems in your RC car. If the steering is working and the vehicle doesn’t move, there might be a wire that has come wobbly at the steering servo.

You may find that your car isn’t getting any power and you just changed the batteries, you might have a loose connection from the battery compartment or pack that’s causing the problems.

Reattaching unsteady connections, and soldering wires might repair the wiring problems. If you are unsure about soldering wires, your hobby shop or RC car repair technician can help.


Gears in an RC car act like the gears in your “big” car. It is possible to have slipped gear on your RC vehicle. Slipped gears keep your vehicle from going forward or backward.  If the gears are not stripped, they need not be replaced.

The pinion gear might need tightening or lined up to the spur gear. If your RC vehicle is making grinding noises and won’t move, it is probably a gear problem. If you are expert in the repairs of your RC car, check out the gears. However, if you are unsure about the issues take it to a professional for repair work on gears.


Make sure your controls are in the correct position. Sometimes controls get reversed. You need to check the settings of your transmitter first. Switch the controls back to normal, and that should fix the problem.

Steering Arm

The steering arm. Your RC car may run okay, but it vibrates when you drive it. It might have a broken steering arm. Check inside the car for a narrow piece of plastic similar to tie rods positioned on a full-size car.

The rod will be close to the front tires. If one is broken, you might swap it out with a stiff wire piece. You can also get replacement wires from your local RC car hobby shop.

The wheels on your RC car are what drives the car over terrains.  If your wheels seem to spin in opposite directions, don’t worry. Rotating in opposite directions isn’t a problem since wheels turn in a different direction when you spin them. Mot RC cars have a differential that makes wheels turn and go around corners.


Some RC cars have tires that fall off the rims. Put a bead of glue on them to keep the inserts inside the rims. Gluing the tire to the rim will prevent it from falling off.


RC cars have shocks and if they leak this could is a problem. Shocks often leak due to extreme pressure caused by expansion of the air due to heat. If shocks leak a small amount, that’s okay. If it’s leaking excessively, you might need to replace and rebuild the shocks.

Radio Control

Radio control does not work. If you run a nitro or an electric car, there is little difference in the troubleshooting processes. Make sure the aerials are not damaged, extended and screwed in correctly.

Check the batteries and makes sure they are charged. Keep the proper number of batteries in the transmitter and in the car. Make sure the transmitter aerial fits tightly but not too tight.

If you have an overtightened aerial, that could lead to a loose mounting screw in the transmitter. Undo the plugs in the receiver plus in the transmitter put them back in making sure they are secured correctly.

Smoking Engine

Scary! Your engine is smoking.  If your motor is running hot, you may see smoke coming out of your motor. The fix is to keep your temperature under control. Avoid resistance on the RC car.

Check for dirt in the engine. If there is dirt in the engine, remove the bell housing and clean it out. Use an air compressor or other methylated substance. Be careful.


Listen to the transmission. One of the costliest things on your RC car to repair is the transmission. Diagnosing the problem may man taking out the entire transmission and disassembling it. If you can go into reverse, you may have internal damage to your transmission.

It would be best to take it to a hobby shop for a professional to repair the transmission. Or, you may need to purchase a new RC car.

Related Questions:

What brands of RC cars are the best and have the fewest problems? Choose RC cars that have high ratings especially if you are a novice in the RC car world. You can look at TRAXXAS cars (Click here to see if the Slash is better than the Rustler) that are fast, durable and made high quality.

A TRAXXAS car rarely needs to have parts replaced. These cars are a bit expensive about $300 and may not include a battery pack or charger.

Watch out for Exceed cars. They are inexpensive, and the parts are of good quality. Get spare parts when by these RC cars to avoid the $10 shipping charges to send the car back and forth to fix it.

Another RC car brand is Tamiya. They have been in business for over 30 years and are nice. Parts don’t break often, but the cares are slower than other brands.

Why won’t my remote-control work? Several reasons why your car is not answering the remote control. First, the batteries are dead. Check out the batteries in your remote control. Get new batteries, replace them and try it again.

You may have a loose wire inside your remote control. When electricity flows, the remote control will work properly. Wires need straight contact among the connections inside the controller. Check to see how if the wires need to be reconnected.

If you have multiple cars, you might be using the wrong remote. Test it on another car. If that car works, then your problem is solved.

I washed off my RC car, and now it doesn’t work, what can I do? Let your car sit for a bit and totally dry off. If it still doesn’t work, you may need to open it up and complete dry out the parts. Usually washing RC car will not cause problems but there may be loose wires, or the servos need to be dried out.

I have problems with my RC car. When I try and move it forward a red light on the speed controller lights up, and the car won’t move. How can I fix this? Check to see that something is not mechanically holding back the motor from turning. Check for two screws that hold the motor to the gear case.

Remove these screws and pull out the motor turn the motor by hand. If you can’t turn the motor by hand, the motor might be bad. If the motor runs easily, try to roll the tires by hand. If they don’t turn easily, you have a problem with the gearbox.

If these problems are not on your car, try the electronics. The battery and electronic speed control might indicate a blown a fuse or a low battery. Check the battery first by using a voltage meter. It the battery reads 6 volts or more, the battery is ok.

Disconnect the motor leads and connect the leads to the voltage meter to the speed control. Turn the car on and pull the throttle. See voltage reading. If the voltage checks out, your motor might not be running smoothly.

A locked motor won’t work and may damage speed controls. If all else fails, take your car to the hobby shop or an RC car repair professional. If your RC car is new, it should be under warranty.

My RC car only drives backward, so what do I do? Check the batteries to see if perhaps they are in backward. You might also have a servo reverse switch on the remote that is on.

Make sure your servo is centered and check the plate that controls forward and backward movements. It might be dirty and need to be cleaned. Use some fine sandpaper to polish the servo being damaged. You might also have gear damage or a burned-up motor. Try plugging in a second servo to make sure the receiver battery pack is okay.

Is my motor system broken since my car quits? When your motor system quits, install a second motor in the car and do some necessary testing.

How do I fix an unresponsive radio system? If everything is dead on your RC car or the lights are on, and nothing is working, the first place to look is the wiring. Look at the wires that run from the battering into the motor. You may have damaged wiring and need to re-wire your connections.

Why is my receiver not working? A receiver can die on its own which causes the steering wheel or the throttle to stop working. Test with a second receiver or try another radio system. You can also plug in your throttle and steering wheel into another vehicle and doing basic bench testing.

I can’t get my on/off switch to work. What should I do? On and off switches go bad. They look okay when you glance at them and seem to turn on and off, but internally no switch actions go on. Sidestepping the switch by joining the two wires may rule that out.

Take the switch case away from the switch and make contact connecting the terminals but don’t cut any wires. If the switch has problems, you can connect the switch leads and keep them always on.

However, get this fixed. It is not good for your RC car’s system to always have the incoming power on. On and off switches in RC cars are crucial parts of the system and should be used as initially installed.  Always unplug and turn off your RC vehicle when you are not using it. Turning off your RC car when not using it will keep things running well.

What is an analog servo? Analog RC car servos are the standard servo for your car. This servo regulates the speed of your motor by sending on and off pulses.

The longer the on plus is set to the server, the faster your motor spins and the faster your car will go. An analog servo sends a continuous 50 voltages each second and can send up to 300 voltages a second. The major drawback to an analog servo is the delay in reacting to commands.

What is a digital servo? A digital RC servo runs different than an analog servo. A digital servo will provide faster response times and quicker acceleration to your remote-control car.

When you use a digital servo, you have the immediate feel of the controls. Your digital servo will produce higher speeds and acceleration and have a better holding capacity.

My RC car suddenly stopped. It was working the last time. What should I do?

Most problems are simple. Your throttle operation stops or your steering stops. These are simple fixes, but you should really check out other parts of your car, too.