Cleaning And Replacing A Control Box

How To Clean And Replace A Control Box?

The engine control module, popularly known as the control box, is an important component in any vehicle. The control box monitors the electric transmission in the vehicle and ensures all components are well powered. The control box relies on impulse signals from other components of the vehicle. They will send these impulses to show that everything is working well or when there is a problem with your electrical system. Cleaning and replacing a control box will help you solve many electrical problems that come up.

When the control box receives an error, it will interpret them into codes. It will thus display them on the dashboard by lighting the appropriate signals depending on the causes of the error. It thus makes problem identification easier and ensures your engine is always working at peak performance. Many car components rely on the control box, and when it malfunctions or isn’t operating at peak performance, your car risks not starting or makes driving dangerous.

When do you need to clean or replace a control box?

Identifying problems with the control box is easy as they will be displayed on the dashboard. You can also perform a diagnostic test on your vehicle, and it will generate and interpret the codes from the control box showing its problems. Here are some instances you will need to clean or replace the engine control module;

  • When the component is corroded: The control box is bound to become corroded after years of usage. The dust and other harmful particles that stick to it will cause corrosion and thus make it ineffective. Getting a replacement, in this case, is the best option.
  • When the control box is burnt out: The control box can get burnt out when there is a faulty electrical module on your vehicle. A shorted solenoid is among the main causes of these problems, and in this case, you will have to replace all burnt components with the control box. It will prevent it from burning out in the future.
  • The control box is bound to suffer from wear and tear just like any part of the vehicle. Being exposed to natural elements, especially water, will make it break down. Cleaning and replacing a control box will depend on the extent of the damage caused.

How to Replace A Control  Box

You first have to ensure the electrical problems on your vehicle don’t stem from the dynamo or faulty wiring before incurring the replacement cost. Checking the state of the control box will help you make this decision and thus help you get the best value for your money. First, remove the control box and check for corrosion or dirt. Replace the parts if they are too corroded for repairs.

#1. Finding The Right Fit For Your Vehicle

The control box comes with model specifications from the vehicle manufacturer. If you get the wrong one, it will not fit or fail to perform together. Identifying your engine size, fuel type, part number, and vehicle model will narrow your search and make it easier to get the right option. You can consult the vehicle manufacturer or your local dealer for this information before making your purchase. You can begin the replacement works once you find the components.

#2. Disconnect the Battery First

An essential step is cutting power transmission to the control box by disconnecting the battery. It will prevent sparking or shorting if the components come into contact with one another. Unscrew the control box from its position and carefully remove the rubber mounting around it.

The engine control module has resistors mounted on its underside. Be careful not to upset or disconnect them in the process. You can now install the replacement once the previously damaged component has been fully removed. Reinstall the seals and remove all other rubber mountings around the control box.

The replacement control box should fit perfectly in place. Screw it firmly and reconnect the battery cables. You can test it by turning on your engine and checking to ensure the dashboard lights are out. Driving the car at different speeds and monitoring the lights until they go off will also help you fix this problem. Some vehicles will require reprogramming after cleaning and replacing a control box, and you can do that too or visit your mechanic for assistance.

How To Clean A Control Box

When your control box is not too damaged, cleaning it is a good solution. It will help remove mild corrosion or dust and mud that has accumulated on it for a long time. Even though it is only applicable for a selected number of situations, it is a cheaper alternative compared to full replacement. This is how to clean the control box;

#1. Disconnect the Battery

Disconnecting the battery will cut the power supply to the control box, thus making disassembly easier. Proceed to unscrew the screws holding the control box in place and carefully remove its rubber mountings. You can now moisten your cleaning cloth with paraffin and begin the process.

#2. Wipe it off Carefully

Do not wipe down hard on the control box as it contains resistors that might get damaged in the process. Identify spots with dust and mud and wipe them down gently. You should ensure that the paraffin doesn’t contact the rubber parts as these can easily absorb and hold onto it. It could cause a fire when you start your vehicle from the generated sparks.  In case of an emergency, check out this guide explaining what should you do if your car catch fire.

You can use methylated spirit to clean the terminals. It evaporates easily and fast, and you thus don’t have to worry about it accumulating on them and causing corrosion. The control will become corroded if cleaned with water.


Cleaning and replacing a control box can be completed easily with the right knowledge of vehicle components. You will not experience electric problems or your car failing to start because of these problems. After cleaning, you should always ensure that the control box is completely dry before refitting it into your vehicle.