what-limp-mode
Auto Parts,  Auto Engines,  Cars

What Are The Major Causes And Solutions Of Limp Mode?

(Updated 7/25/19) If you have experienced a lose of power while driving, but later the cars power comes back when you restart the car, you may have just experience your car's limp mode. Limp Node is most likely to occur when you driving at high speeds or accelerating quickly. Your car's computer want to protect you form causing damage to your car's engine.

Limp mode is the safety feature built into many cars to protect the engine from damage. If your pushing your engine to the limit, limp mode might be activated to prevent damage. Sometimes the computer will put the car in limp mode when it's not necessary. Sometimes, just restarting the car after waiting 15 seconds will take you out of limp mode.

If you notice the check engine light flashing on the instrument panel, this may be an indicator of limp mode. One way limp mode tries to protect your engine is lowering engine power levels.

When I notice my car is in limp mode, it my car's way of saying, "Hey, your car might be in trouble, check it out as soon as possible." The trouble might have occurred in the car’s transmission, computer, sensors, fluids, or wiring. To figure out what going on, continue reading about possible problems and solutions.

Definition: Limp Mode

limp mode car

Photo Credit: http://www.bimmerfest.com/forums/showthread.php?t=719830

Lets take look at what limp mode is exactly:

The car has several computer like modules that can detect problems. If one of these modules decides there's a problem, it will try to prevent damage, sometimes by lower power or preventing the car to shift into a particular gear.

This results in problems driving the car normally. The computer modules are trying to get you to fix the problem, and will usually warn you with the check engine light. You are in 'Limp Mode.' 

If the check engine light is on this doesn't always mean limp mode, but it's important to check. 


Now that we have a general idea of what is limp mode, let us consider its main causes and some solutions:

Cars have an ECU or electronic control unit that controls the electrical systems in your car. Here are some parts of the ECU: the engine control module, the transmission control module, the braking control, central timing module, and the suspension control module

When a car’s computer system (ECU) detects an engine problem, a sensor issue, a braking problem, or it detects a trouble in the transmission, it can protect the car by using limp mode. A trouble code is store for you or a mechanic to look at if you have a code reader. 

The computer system general does a great job ensuring the smooth operation of your car. It's constantly monitoring the car’s smooth performance, checking for errors, sensors issues, and comparing data. Once any of the sensors indicates something out of parameters, it may alter the cars behavior insuring damage doesn't occur.

If a driver has made modifications to their car, the computer may not understand and place the car in limp mode. Sensors or wiring could be malfunctioning as well. To fix this first we must investigate the possible problem. 

To find the precise causes of limp mode, get your gloves and gear ready:

Limp mode can prevent engine damage or just prevent you from normal driving if nothing is wrong. Finding out the problems takes using a code reader or going to  a service station.

If you have a code reader (OBD2 scanner)  then you can look into the reason the car says is causing the difficult and try to fix it if needed.

If you don't have a scanner it may be difficult to determine the precise problems, but a visual inspection might show low fluids, loose wires, loose part, or damaged parts.

OBD2 scanner

Major Causes of Limp Mode

1. Transmission Issues

transmission-issues

When the transmission control module finds an issues, possibly due to your car’s transmission getting interrupted, damaged, or it might detects strange sensor readings, it may put the car into limp mode.


The computer reads many sensors but if one is not working, this loss of communication will generate a code and the check engine light should go on.


Transmission Control Module

2. Error in the Boost Deviation of the Car

limp mode car

Photo Credit: http://myusedcarblog.com/what-is-limp-mode/

If you get an error from the code scanner that indicates a boost deviation, you might have bad sensor or a fuel pump problem. Investigate the code error and find the common reasons why the code usually occurs. 


If you feel a sudden and abrupt pause of the car, this may mean that limp mode has set in and taking control of systems that might cause damage if used. 


Checking the fuel pump, sensors and electrical connections, vacuum lines, or anything that could clog, is a good idea. 

Pressure Sensor

3. A Problem in the Cars Wiring System

cars-wiring-system

If your car is older, drives in bumpy areas often, or has had a leak, you'll need to check you wiring for problems when your car goes into limp mode.


Look at the OBD2 scanner code, if you have one, and start looking at the wiring for the part that is indicated on the code.


The wiring inside the car’s hood is prone to corrode, break or tear. This can cause many electric problems to occur. Connect/replace any wires if needed.

Wiring Connectors

4. Leakage in the Battery Acid of the Car

limp mode car

Photo Credit: http://www.audizine.com/forum/showthread.php/561015-Limp-Mode-ESP-light-EPC-light-P2138-Throttle-Pedal-Position-Sensor

Car batteries are important for the electrical systems of your car and provide power to your electronic control unit (ECU). If they either leak or are completely drained, the cars computer system can have problems.


This common problem may occur due to damaged wires or memory lose in the ECU. Battery troubles can cause wires to corrode, voltage fluctuations which might damage electronics, and lose of power to the computer.


Replace the battery or wiring if needed. Sometimes a simple cleaning of contact points can solve the problem.

Car Battery

5. Modification to Your Car

turbo charger

Many people like to modify their cars. They install new parts so their car will perform better. Aftermarket parts may not fit within the parameters that the ECU electronic control unit has set. 


Some people choose to modify their car and ignore the check engine light or reset/clear limp mode warnings from the car.


Sometimes they use a OBD2 scanner to clear codes and get their car working normally again. While this may not cause engine problems, there's a possibility it could.

Turbo Charger

6. Solutions - Do it Yourself or Get Help

DIY or Mechanic

Do it Yourself

Understanding the reasons behind why you car's check engine light is on or why limp mode has occurred can bring a lot of relief. You have a better understand of what is wrong and can work towards fixing it. 

Getting an OBD2 scanner to find out what codes are showing up can help you decide what to do next. It is usually easy to use and sometimes helps with practical information on next steps to take. 

Another reason you might want a code scanner is to reset or clear codes that no longer apply. This will stop the check engine light from flashing, so do this only if you've fixed the problem and your sure everything is working.

A visual inspection of your engine might also reveal information for the cause of your limp mode. Be sure to check for leaks, wire connections, and lose parts. Cleaning around hoses and connections might reveal what's going on. 

If it's a simple fix, like replacing a hose or a sensor, then I suggest doing it yourself. If not, get help.

Get Help

Going to a mechanic is the right thing to do when you have little to no experience with fixing issues with your car. There may be many parts that need fixing and a mechanic can read the codes and know best what should be causing the problem.

A mechanic is helpful when solving multiple problems, since they understand how car systems work together.  

You may want to do some research and then decide if your limp mode activating means there's a minor issue and nothing really wrong with the car or if it's a serious issue that need professional help. 

Start Today

Whether you fix it yourself or get help, try not to take too long to solve the problem. If your car does have engine problems, driving it could cause more problems. Usually you want to stop driving the car and get it fixed.

Inspecting your car regularly or getting it service for regular maintenance can catch issues before they become a problem. ​

With the computer systems in your car you'll have powerful information that you or a mechanic can use to diagnose and fix limp mode issues. 

Conclusion

If my truck was in limp mode, I would probably take it to a mechanic, and then get scanner so I would be more informed the next time a problem occurred. That being said, getting a scanner before might be a good investment, at least for some peace of mind.

Cars today have so many sensors and control modules that you'll need to carefully consider whether making a repair is the right call, after you've looked up the code and found out what's wrong. 

The more research you do, the more confident you can be diagnosing and fixing problems. And if your not feeling confident enough, you can always get it repaired by a professional. I hope you found this article helpful and for help with other car issue head to Drivinglife.net