Limp Mode – What Are The Causes Of Limp Mode?

Limp Mode, what is it all about? So many drivers out there don’t have an idea of what limp mode is and it can be pretty scary when your car starts acting strangely for no just cause.

Limp Mode
Limp Mode

This content will be trashed out every detail you need to know about limp mode including its causes, effects, and how to fix it.

So I encourage you to read to the end because the knowledge you will get from this post will be very helpful to you. There’s an adage that says “Knowledge is power”. For more knowledge about the car limp mode, read on.

Limp Mode

If you’re on the road driving and suddenly your car starts slowing down and the ‘check engine light’ came on, your car is most likely in a condition called Limp Mode.

You might be confused or worried on why it happened and how expensive will it be to fix it. Before going into the fixing procedure, you need to understand what Limp mode is.

What Is Limp Mode?

Limp mode is a security feature in cars that activates when the engine or transmission control unit picks up a fault. Once it detects an issue, limp mode will cause the less important parts of the car, like the air conditioning, to switch off, and the speed of the car will be reduced.

This happens, to ensure the fault doesn’t cause anything serious to happen and also helps the car to ‘limp home’. However, the limp mode feature is designed to let you know that there are issues with the mechanisms of your car. When you see such sign, kindly take your car to a technician.

What Are The Causes Of Limp Mode?

Limp mode is triggered by the car’s computer, which receives signs from all the different components of the car. So, when one of the signals is abnormal, the car will revert to limp mode to prevent further damage.

Below are problems that cause signals like this

  • A faulty engine sensors/components/wiring
  • Transmission issues
  • Dysfunctional brakes
  • Clutch, or even low fluid levels.

Engine Boost Control Problems

This is the most common cause of limp mode. Overboost can happen if you have a turbo car, and it is quite critical to your engine. Due to this, the engine control unit will limit the engine power.

Common things that causes overboost are a faulty wastegate, broken wastegate hose, boost control valve, or a faulty boost pressure sensor.

Faulty engine sensors

The engine has lots of sensors that can cause your car going into this mode, and it won’t be easy to find out which one. Do not worry, you will learn how to diagnose it properly on this post.

Engine sensors that can cause limp mode are MAF sensor, engine temperature sensor, boost pressure sensor, or O2 sensor.

Transmission Issues

If you have an auto transmission, the transmission control module can actually set the car into limp mode, when something is wrong with the transmission. Which can be a faulty sensor, faulty valve, low transmission fluid level, or a bad shift solenoid.

Wiring Issues

Wiring issues to the engine or the transmission are also also common when it comes to this mode. The mode can be as a result of a broken wire or just corrosion at a connection.

It can also be a missing boost pressure signal, making the engine control unit not take any risks and set limp mode.

How to Fix Limp Mode?

Fixing this mode frequently needs a full diagnosis to prevent just replacing parts and wasting money.

Below are DIY possible fix for Limp Mode;

Check All fluids

Begin by checking all fluid levels in your car. Including the engine oil, coolant, power steering, transmission, and brake fluid level. If you have an automatic transmission, the significant one is the transmission fluid.

Ensure that these fluids are in good shape and if you can see anything strange with them.

Clean The MAF Sensor

The MAF sensor controls the air-fuel mixture in your car. And can often become dirty, especially if you have an open-air filter. So dust and dirt on the MAF sensor will often cause it to send wrong values to the engine control unit, which may result in this mode.

So, make sure you remove it and carefully clean the sensor with an electronic cleaner. Have it in mind that the sensor is susceptible, and you should not touch it with your hands.

Check & Clean or Replace Air Filter

The air filter always ensure that the engine gets clean air without dust or dirt. If you have not changed the air filter in a while, it can be so clogged that it will cause problems with the intake air.

Check Trouble Codes

If after trying the tips above and the issue persisted, there is nothing more to do than make a proper diagnosis. So, to make a proper diagnosis, you need an OBD2 scanner to check the trouble codes stored in your engine control unit.


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