Most drivers probably have not heard of the Limp Mode feature, although it is implemented on most new cars. Here’s how it works and what to do when your car’s computer triggers this feature. There is also the possibility to disable the function, but it is not recommended.
At any time, an engine or transmission component can fail.
At that moment, modern cars communicate to the driver, via the electronic display or dashboard warning lights, that a breakdown has occurred. But in recent years, a system called Limp Mode has been implemented on most new cars, which limits technical performance.
What is Limp Mode
Limp Mode is an engine protection or safety feature.
Almost all engines manufactured in recent years have implemented this function, which has a double role.
On the one hand, it informs the driver of the presence of a serious fault, which can cause costly damage to the engine.
But, on the other hand, it acts directly on the engine, to limit a possible worsening of the failure.
How Limp Mode works
The main symptoms of Limp Mode activation are:
- the Check Engine light on the dashboard lights up;
- engine speeds are reduced below 3000 RPM, and in some vehicles below 2000 RPM;
- travel speed is limited to a maximum of 50 km/h;
- it is possible that some functions, such as air conditioning or climate control, stop;
- on cars with automatic transmission, the car will shift into a lower gear;
- some vehicles may not be able to leave the site.
So, Limp Mode, which in translation could be called “limping” or “crawling”, drastically reduces the car’s performance. But, in most situations, it allows emergency travel.
This function is intended to prevent the situation from worsening, such as damage to properly functioning engine components or technical sub-assemblies.
In which situations it is activated
The Limp Mode function is activated when the computer detects a serious fault. These faults are signaled by sensors that also have a diagnostic function.
Malfunctions that can lead to the activation of Limp Mode:
- incorrect operation of sensors;
- problems with the electrical system;
- damage to the transmission or distribution;
- loose or damaged wiring;
- brake system malfunctions;
- lack of antifreeze, engine oil or other fluids;
- air flow meter problems;
- incorrect operation of the turbine or DPF particulate filter, etc.
The activation is done automatically, when the car’s computer receives the information from the sensors indicating a problem. Once activated, it is clear that you need to get the car to the service as soon as possible, to do a computer diagnosis.
And after fixing the problem, it will be possible to deactivate it, so that the vehicle can operate in normal parameters again
How to disable Limp Mode
Limp Mode can also be activated due to a sensor error. In which case you can disable this function through a system reset.
How to disable Limp Mode:
- the engine stops and restarts after 5-10 seconds;
- check the fluids (engine oil, antifreeze, etc.) and, if necessary, top up to the optimal level;
- a check is made of the engine wiring harnesses to see if they are loose or disconnected.
If it is an error or a problem caused by these causes, when you restart the car Limp Mode will disappear. But if there is another fault, the limitation of the car’s performance will be maintained.
There are also mechanical or technical options to cancel this function, but it is not recommended to resort to such a solution. Because it has the role of protecting the engine or other components.
Source: www.promotor.ro
