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Remote Controlled cars are a great source of fun for adults and children. Whether one is tearing it up in the smooth racing parks or taking on rough terrain, RCs can be enjoyed anywhere. However, just like most electronic devices, these cars are also prone to wear and tear which may alter the car’s ability to perform as intended. Fortunately, you can repair these damages yourself, but you’ll need to perform a quick vehicle diagnosis before doing so. Being able to diagnose your remote control car is one of the most important aspects of RC ownership. Diagnosis includes examining the fuel levels, transmitters, gears, batteries, spacers, steering, arms and overall wiring. The following tips will help you easily fix your car at home. Doing this will not only help you save a lot of money on professional repairs, but ensure the longevity of your car.

Check the Batteries


Batteries are ‘packs’ of chemical energy that power the RC’s. The first thing you should check when the car has a mechanical problem are the batteries. Are the batteries properly installed? Are they the right fit for the battery slots? Sometimes your car’s problem can be solved by replacing the batteries! If your car’s performance is agging’ or won’t start, the batteries are at fault. Some common problems with batteries include corrosion, disuse, faulty connection, and alternator problems. Check if the batteries hold enough charge. If you haven’t used your RC car in a while, your batteries might have started to corrode and might need replacing. If that doesn’t work, check the batteries’ installation and make sure they are properly fitted.

If the batteries pass these checks, then the problem could be your battery charger. Consider replacing it and see whether the problem is fixed.

Electronic Problems (Wiring and Connections)


If troubleshooting your car for the above problems doesn’t work, then check for a possible error in the wiring configuration. Wiring and connection errors account for most RC cars related problems. Check for the following issues in wiring and connections;

  • Open Circuits – For a connection to be complete, it needs to be closed to enable the current to pass through. Open the RC and make sure all connections, tracing back to the motor (if one is present) and battery, are closed. Chances are your car is not performing as intended because of an exposed or broken wire. If this is the case, consider buying a soldering iron whose temperature can be adjusted.
  • Transmitter Connection Issues – Transmitters in RCs are small handheld devices which send signals to the receiver over a frequency, through a wireless connection (also called a radio transmitter). Checking the transmitter will diagnose your car for possible faulty connections or the other transmitter issues. You can easily open it up and look at the circuit board. Take a picture of how it looked before you opened it to help you put it back together. Most transmitters use plastic hooks in place of metallic screws so be on the lookout for that. You want to make sure that the copper plates touch where the contacts are. If they are not touching, this is probably the cause of your car issues. Try aligning the metal contacts towards you and check whether the connection is complete. If this doesn’t work, you are better off getting a new remote control system. This is cheaper than buying a new RC car.

Fuel and Oil Issues

It goes without saying that most vehicles need fuel to run. If your RC car runs on fuel, you might need to take extra care and maintenance of your vehicle. Check whether your car has enough fuel to power it. If not, consider adding fuel to the RC car. If there is enough gas in the tank and the car is still running poorly, then the problem lies with your fuel line. Check it and make sure it’s in good condition.

Secondly, check the car’s oil. When was the last time you changed the oil? Consider changing the oil, also consider changing the oil in your RC car’s shocks. Additionally, if your car is discharging oil when it’s running, the car’s shock cap might have cracked. This might cause your car lack of rebound when shocked. While you are at it, check the car’s shocks for possible debris stuck in your car’s suspension that might affect your car’s performance. Debris might range from hard rocks to soft grass. If your car is still performing off-color, then the problem might be listed below.

Related article: 5 Best RC Cars in 2020: Your Ultimate Buying Guide – Best RC Cars

Servo Transmission Problems

Servos in RC cars are primarily used for converting electrical signals into movement. The word ervo’ can interchangeably be used with servomotor. Other than the battery and wiring, if your car isn’t starting it could be a sign of a faulty servo. Luckily there are ways you can change troubleshoot and diagnose, to be completely sure that the servo is faulty;

  • First, check whether the car is responsive to other mechanical and electronic commands.Test this by using the cars remote control to input certain electrical commands. If it responds to some and fails to respond on others, the servo is probably faulty.
  • Secondly, match the frequency of the servo in use (normally used by the transmitter) with another receiver. Interchange the servo to the new receiver and check whether it is working. If the servo doesn’t work on the new receiver, then you have the cause of your RC car’s problem. It would be best to replace the servo as opposed to fixing it unless you possess the technical know-how.

Other Mechanical Issues

If you’ve correctly diagnosed your car for electrical faults and your vehicle’s mobility is still in question, consider checking the following mechanical issues.

  • RC cars apply the principles of normal cars such as transmission systems and steering which make it easy to drive. Just like the check-engine light indicates a problem with the car’s engine and gear system, you can easily diagnose a flaw in the car’s steering or gearing system. You will notice a problem with the car’s movement; either slowing down or totally stopping when in motion. Additionally, if a gnashing or grinding sound comes from the car, this shows there is a problem with the car’s gears and steering. You want to then check if the gears are totally worn out or just out of place. If they are out of place, you should easily put them back into place. If they are worn out, a total gear replacement will be required.
  • In close connection with the cars mechanics are the spacers, a-arms and steering arm. There are different types of spacers including floating slip-on, floating bolt-on, hubcentric slip on and hubcentric bolt. All of these spacers are made from different materials such as steel and aluminum. This means they will react differently to shock. Make sure you identify with your car’s type. Additionally, make sure they are functioning well and are able to properly lift (and support) the car. If they are not, you should consider replacing them.
  • Spacers work well with a-arms. A-arms are hinged suspensions that are mounted near the wheel to help with the shock and rebound mechanics. Check for possible debris such as dirt, grass, and rocks that are stuck between the spacers. This is important as they might be affecting your car’s performance, shock and rebound mechanics.
  • If your RC car is still plagued with mobility problems, then the steering arm might be malfunctioning. The steering arm works together with the steering gear to enable a smooth turning. Remember the servo mentioned above? The steering column on an RC car should meet the servo either with a plastic rod or a wire. Steering problems are usually easy to diagnose for as the car will have issues moving in the direction you instruct it to. Additionally, you need to be on the lookout for this if your car lacks power and direction when turning. Take a look at the cars steering wire and adjust accordingly. If it is broken, use glue or wire to reattach the servo to the steering arm.
  • Lastly, check the RC car’s engine-the motor. The motor is the driving force behind your car. Most RC cars are usually equipped with motors that are powered by alkaline or NiCad which generates a reasonable top speed making these gadgets fun to drive. Sometimes they get totally worn out and your car might require a new one.


Most problems listed above are technical and advanced. You should first do a check for simple problems such as worn-out plastic parts or faulty tires before opening your RC car up. Some problems are simple as they would require glue or adhesive to fix. Do not risk opening your car before you diagnose your car with fairly easier problems. Just like on a normal vehicle, performing a diagnosis on your RC car could be challenging, extensive and time-consuming. If your car’s problems still persist, go ahead and diagnose for electrical or mechanical issues. It is advisable to expertly eliminate one problem as you progressively diagnose your car. This way you’ll be back to enjoying your RC in no time.

Henry Brighton

Henry Brighton

Henry Brighton is an avid RC car enthusiast with extensive knowledge about RC cars. He has been driving them since he was a child and has honed his skills over the years. He loves to share his passion and expertise in the field of RC cars.

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