What Are The Major Causes And Solutions Of Limp Mode?

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If your car starts losing power and you decide to restart the engine, and normal power comes back, you can assume your car was in Limp Mode. Limp Mode is most likely to occur when you car traveling at high speeds. If your driving on the highway, expressway, over hills, and pushing the engine fairly hard, this high power might can signal your engine control unit to slow down the engine, to prevent damage from occurring to your car.   

You might notice the check engine light is on or flashing on your dashboard. Limp Mode might take place when your car is running at a lower speed and low power as well.

Simply put, the computer system in your car is alerting you to the possibility of car problems. It could be any number of issues such as wiring, the transmission, and sensors. The car will not accelerate and may not shift normally, indicating that you need to take it to a mechanic or use a scanner (Amazon Link) to find what the problem is.

Definition: Limp Mode

limp mode car

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

To explain better about what limp mode is exactly, lets talk more about this safety feature that some cars have:

When a signal from one of the car's sensors or one of the computer controlled systems of your car is not within normal range the car will switch to safe mode. This safe/limp mode can do different things depending on the signals it is receiving. It will try to prevent damage to the car, so you can take it to a mechanic as soon as possible.

The result of limp mode is often a loss of power in the engine and sometimes a restriction in one's ability to shift the car. If there's a minor problem there will be a dash light that will turn on, such as the check engine light. These signals to the driver, enable her or him to know that some problem exists with the engine or electrical system. 

Now that we have a general idea of what limp mode is, let's find out what some main causes and  solutions are:

When a car’s computer system detects a particular problem, such as a sensor issue, or it detects trouble in the transmission, it will help the driver prevent any major damage from occurring to the car by limiting functionality of some the car systems. To resolve the problems with your car you'll need a diagnosis. And you'll likely be stuck in limp mode until you resolve these problems.

Sometimes restarting a car will take the car out of limp mode, because it was a minor issue.  

But, if the car's computer system has a wiring problem, it may limit shifting, and other functions. If the boost control has issues this can also put the car in limp mode. What normally happens is the computer will limit your RPMs if there's a boost control issue. 

Once any of the sensors indicates a problem, the system typically changes how the car operates; hence, resulting in limp mode.

Lets discover the more reasons for Limp Mode, and what to do next.

When a driver encounters limp mode they can take the car home and try to solve the problem themselves, or take their car to the next service station. If you don't have the equipment or knowledge of specific reasons your car might go into limp mode, it's better to ask someone with more experience for help. No matter where you are or where you are heading, limp mode can help save your car costly repairs if you take care of the issues right away.

Major Causes of Limp Mode

1. Transmission Issues

transmission-issues

When computer control of your car’s transmission is interrupted, or the transmission has mechanical problems, damaged can occur. Limp mode occurs when the car's computer senses a loss of communication or a mechanical issue with the transmission and prevents some or all shifting from occurring.

2. Error in the Boost Control 

limp mode car

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

Boost errors are usually sent to the computer via codes. Your car might suddenly pause and a limit to the car's RPMs may occur. This loss of power indicates your in limp mode.

3. A Problem in the Cars Wiring System

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The wiring under the car’s hood is prone to corrode, break, or become lose. This can cause  electric issues and causing the computer to think there's a problem with one of the car's systems. Limp mode will occur in different ways depending on the wiring issue. 

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

This is another common problem that affects the wiring of cars. Battery troubles, corrosion, voltage issues, and failure of the engine can occur.

5. Low Fluid Levels

If you have a leak or haven't checked your fluids for a while, it's time to see if everything is filed to the correct level. If not, this can signal your car to go into limp mode. Your transmission might not shift. 

6. Sensor Issues

auto sensors

www.bourns.com/products/automotive/automotive-sensors

If you have a leak or haven't checked your fluids for a while, this may be the problem. Sensor signals can cause your car to go into limp mode. 

7. Understanding Your Options

                           (Amazon Link)                                                        (Amazon Link)

When trying to fix your car, you may be able to diagnose the issue using an OBD2 scanner. Theses tools can be handheld or Bluetooth enabled and work through an app on your phone. 

When using these tools you'll need a car that is from 1996 or older. You just need to access the port that is usually located under your car's dashboard and plug in the unit. Follow the direction for the unit you've purchased.

These scanners start around $10 (Amazon Link) and go up to hundreds of dollars. Usually you can get a one with lots of good features for about $40.  


When you car is in limp mode, your car might self correct issues the next time you restart the engine. If not, a scanner can help you when the car stays in limp mode. It tells you what the computer has determined the problem may be.

For example, a sensor could have recorded there's a problem, and told the computer. If you replace the part that the code indicated may be faulty, then you've solved the problem.

But... it might not be the part that the code indicated because sometimes sensors and wiring might not be working correctly. So caution is important when using the scanner codes. After you can look up the code, either on the device, the included manual, or the internet, also check any related problems that may have set off the code.  

Looking up specific manufacturer codes for your car on the internet can be helpful in figuring out better how to solve the issue with your car. Some scanners come with specific car manufacturers codes. 

Turn Off the Check Engine Light 

One nice thing you can do with a OBD2 scanner is turn off the check engine light if there's a simple fix that you car able to do on your own. 

On my car the tire pressure light goes on all the time even if the tire pressure (Amazon Link) is fine. One way to turn off the light is using a scanner. 

With more serious issues you'll want to be sure you've really fixed things before turning off any dashboard lights. You want to know if there is a problem and not ignore dashboard lights. 

Finally, it's helpful to get advice and help from a mechanics when working on your car. Even if you think you've fixed the problem. Replacing a part might not be the real issue, and it may be something related, but completely different. Always get a fresh pair of experienced eyes to help you solve the issue. 

Conclusion

If you find your in limp mode stop using your car as soon as possible. Either get a mechanic to fix it or try using a OBD2 scanner to do it yourself. 

Limp mode is an issue that can be solved with some help from a scanner, and some experience with fixing cars. It may be a small issue that you can easily solve yourself or you may need to do some lengthy research. You may save time and money by learning how to scan for codes and look up solutions carefully. 

More serious codes require more research and a thorough check of possible causes of the problem. Having a professional repair your car is advised when you have little or no experience with the car's system to be fixed. 

It may be frustrating to be in limp mode, but it does help you avoid further damage to your car. If you've fixed your car yourself through scanning and repair, then you've accomplished something a majority of people are unwilling or unable to do.  Nice job!