Mitsubishi Evo X 4WD System Service Required: Causes & Fixes

The “4WD System Service Required” warning indicates an issue with the Mitsubishi Lancer Evolution X’s 4WD system. This warning message may be caused by a bad 4WD actuator, faulty wheel speed sensor, fluid leakage, transfer case issues, corroded wires, manufacturing defects, or inadequate maintenance. 

To address the warning, replacing faulty components, fixing fluid leaks, rectifying electrical issues, replacing malfunctioning wheel speed sensors, performing regular preventive maintenance, and exploring any recall/warranty options are essential. Seeking professional assistance is crucial to prevent further damage or risks and ensure the vehicle’s proper functioning and safety.

This article will further explain what the 4WD system service is, its causes, and how you can fix them. 

What is Evo X 4wd System Service Required?

“4WD System Service Required” is a service message found on Mitsubishi Lancer Evolution X’s(Evo X) information panel or dashboard. The warning indicates a problem with the vehicle’s 4-wheel drive (4WD) system.

The 4WD system in the Mitsubishi Lancer Evolution X is complex. It distributes power to the four wheels of the car. This ensures the wheels spin simultaneously, enabling better traction and improved handling on off-road tracks. 

When Evo X 4WD System Service Required is displayed, some associated signs follow. This includes symptoms such as difficulty shifting gears, an unresponsive system, Engine stalling, Bad fuel economy, etc. Your vehicle may also go into a limited mode to protect the drivetrain.

Nevertheless, you must address this issue promptly to prevent further damage to your vehicle. An authorized and licensed mechanic can help you by diagnosing and resolving the Evo X 4WD System.

Causes of Evo X 4wd System Service Required?

Below are the most common causes of the 4WD System Service Required warning.

A Bad 4WD Actuator

An actuator is a part of the drivetrain system that engages or disengages the 4WD system mode. It is the singular component that enables drivers to switch between 2WD and 4WD. The actuator controls the power transfer from the engine to the wheels (front and rear). 

Furthermore, the actuator sends the signal that activates the transfer case. This also enables all four wheels to receive an equal level of torque from the engine. 

If an actuator becomes terrible, the entire 4wd system will be disengaged. You will notice symptoms such as a difficulty in accelerating, rough idling, smoke from the exhaust, etc. The “4WD System Service Required” message may also appear on the dashboard to alert the driver of the problem. 

Ignoring the issue can further damage the drivetrain and compromise your vehicle’s safety and performance, especially in challenging or off-road driving conditions.

It is not recommendable that you drive with a bad or faulty actuator. 

Issues with the wheel speed sensors

The wheel speed sensors monitor the rotational speed of each wheel, and this information is used to control the 4WD system. A sensor failing or giving incorrect readings can cause the 4WD System Service Required warning. 

Fluid Leakage 

The 4WD system relies on specialized fluid to operate correctly. Parts like the gearbox and the transfer case need adequate fluid (engine oil, oil filters, etc.) to work efficiently. 

If there is a leak in this system, the fluid level will drop, causing problems with 4WD system engagement. 

Problems with the Transfer Case 

The transfer case distributes power between the front and rear wheels. Problems in the transfer case may arise from low fluid levels, bad gears, bearings, loose chains, etc. Signs of a bad transfer case include hearing grinding noises, puddles of grease under the car, and other gear-shifting issues.

Problems in the transfer case can make it difficult to engage or disengage the 4WD system properly. This could result in a vehicle getting stuck in 4WD or being unable to shift into 4WD mode when needed. To prevent this from happening, your EVO X will display the warning message “4WD System Service Required”.

Wiring and Electrical Issues

Electrical issues such as a blown fuse, corroded wire, or faulty connections can create problems for the 4WD system in your vehicle. This would also cause your vehicle to display  “4WD System Service Required”.

Manufacturing Defects

In rare cases, a manufacturing defect in a specific 4WD component may cause problems.

Inadequate or Neglected Maintenance 

Failure to perform maintenance as the manufacturers intended may also lead to a “4WD System Service Required” warning.  

Fixes for Evo X 4wd System Service Required

Below are fixes you can apply to resolve the  4WD System Service Required warning.

1. Replace Components

If components like the 4WD actuator or transfer case are found to be faulty or worn out, they will need to be replaced with new or rebuilt units. 

2. Fluid Leak Repair 

Inspect and repair any fluid leaks in the 4WD system. Replace damaged or worn-out seals, hoses, or other components as needed. After the repair, refill the fluid reservoir with the appropriate fluid type to the recommended level.

3. Resolve all electrical issues

If an electrical issue causes the problem, you must inspect all electrical connections, sensors, and control modules related to the 4WD system. Once the source of the problem has been identified, appropriate repairs or replacements should be carried out to rectify the electrical fault.

4. Wheel Speed Sensor Replacement

If the wheel speed sensors are malfunctioning, replace the faulty sensors to restore proper functionality.

5. Carry out preventive Maintenance 

Ensure that the 4WD system receives regular maintenance per the manufacturer’s recommendations. This includes routine fluid changes, component inspections, and other scheduled services.

6. Recall or Warranty Repair

If the issue is related to a manufacturing defect, check if there are any recalls or warranty coverage for the specific 4WD component. The manufacturer may cover the repair or replacement in such cases.


The “4WD System Service Required” warning is a serious matter that should not be ignored. Ignoring this warning can lead to accidents and compromise the vehicle’s and its occupants’ safety. It would also affect the vehicle’s drivability and handling.

Always try to consult the Mitsubishi service center for help with the necessary repairs. Fixing complex issues without the proper knowledge and tools can lead to further damage or safety risks!

  • Edmond Davis

    I'm Edmond Davis, an automotive expert with years of experience in vehicle repair, performance, and safety. I graduated from the University of Michigan with a degree in Automotive Engineering and have worked with major companies like Ford, GM, and Chrysler. I'm a trusted source of information for anyone looking to learn more about cars or improve their driving experience.

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