Can a Wheel Speed Sensor Cause Limp Mode?

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It is challenging to find a non-computerized car today.

Modern manufacturers equip vehicles with hi-tech systems that can mitigate a lot of car defects.

These computerized systems signal car dashboards when problems occur and ease the troubleshooting process.

The vital question, therefore, to ask ourselves is, can a wheel speed sensor cause limp mode?

Can a Wheel Speed Sensor Cause Limp Mode?

When a faulty wheel speed sensor sends wrongful signals to the car ABS, the car computer system will activate the limp mode to protect other essential components. This will disable certain car functions, such as shutting down the AC.

Faulty wheel speed sensors send wrong signals to the ABS control unit.

This generates a trouble code which will indicate a trouble light. In case you suspect a defective sensor make the following diagnosis;

  • Check for fault codes; Fault codes are usually stored in the vehicle’s computer and give information on the cause of the limp mode.
  • Look at the wheel speed sensors; Physically inspect the sensors for any damage.
  • Measure the voltage on the wheel speed sensor plug; Sensors are composed of electronic components that require power checking. The voltage checks whether the power supply is okay or has a short circuit. If the sensor is faulty, replace the wheel speed sensor with a new one.

What is a Wheel Speed Sensor?

A wheel speed sensor or a vehicle speed sensor is an electronic gadget used to monitor the rotational speed of a vehicle wheel.

It sends the information to the vehicle’s anti-lock braking system (ABS).

The wheel speed sensor is essential in controlling brakes and ensures the stability of a car.

It is usually mounted on the wheel hub and sends the information it receives to the vehicle computer.

The vehicle computer uses the wheel speed sensor data to adjust its brake system to ensure a smooth stop.

A limp mode is a state in which the vehicle’s computer system detects a fault in the engine, reducing engine operation to provide safety and reduce further engine damage.

A car in limp mode will minimize power mode to limit the output of power to safeguard the engine and other components from further damage.

How Wheel Speed Sensors Work

All the wheels of a car are usually attached to wheel speed sensors.

The sensors are made of an electromagnetic induction sensor head and magnetic ring gear of ferromagnetic material.

The wheel speed sensor’s function is to monitor and relay the wheel speed data to the ABS control unit of a car.

The wheel sensor detects the wheel rotation frequency and calculates it to the vehicle speed, which converts the information into signals.

Once received, it is interpreted by the ABS computer system to activate a different set of actions on the vehicle.

Various Types of Wheel Speed Sensors

There are two main types of wheel speed sensors passive and active sensors.

  • Passive wheel speed sensors

These types of sensors send analog signals in alternating voltage form to the ABS control unit, where they are analyzed and utilized.

Each wheel of the vehicle creates a unique AC signal.

These signals can only be active when the wheel’s rotational speed is fast. They do not read at a low rotational speed.

  • Active wheel speed sensors

These sensors can detect the rotational direction of the wheel and record the signals using a magnetic pulse sensor.

They function in various temperatures and provide output to the ABS in digital signal form. The ABS and other car systems use the information provided.

Active wheel speed sensors are not as sensitive as passive sensors.

How Limp Mode Works

The limp mode shields important car components when the car computer system detects faults in the engine that could cause further damage.

When the limp mode is active, the car’s engine will be limited to certain functions.

Some common causes of limp mode are blocked air filters, faulty vehicle sensors such as wheel speed sensors, inadequate vehicle fluids or oils, and failed transmission.

Consequences of Driving With a Faulty Wheel Speed Sensor

A vehicle wheel speed sensor is essential to ensure users’ safety. It works with the ABS to provide a car that can have an emergency brake smoothly.

A broken sensor can cause you to lose control of your vehicle and cause a crash.

Broken wheel speed can make the entire ABS not function correctly, impacting other systems in the car, such as traction control and stability.

Inaccurate reading of the vehicle speed is another effect of driving a car with a faulty wheel speed sensor leading to increased fuel usage.

Common symptoms of a faulty wheel speed sensor

The first warning signs that your wheel speed sensor may be faulty are;

  • Presence of a warning light on your dashboard.
  • Unusual noises when braking.
  • Difficult cruise control of the car
  • Sudden accelerations
  • Reduced fuel efficiency
  • The vehicle does not respond to gear.


The wheel speed sensor of a vehicle is an important safety feature. A glitch in the sensor can cause defects in other vehicle functions leading the car to limp mode.

Constantly consult your mechanic to check your vehicle speed sensors to avoid further damage to your engine and protect you from losing control over your car and causing accidents.

To ensure your wheel speed sensors are correctly functional, clean them regularly, and check for damage and wiring.