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How to reset ECU on Audi & Volkswagen vehicles?

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How to reset ECU on Audi & Volkswagen vehicles?
Looking for ways to reset your Audi or Volkswagen ECU? ECU reset, or simply electronic control unit reset, is a simple way to reset control units in your car after making changes. While resetting isn’t always necessary, it can help when certain functions don’t work after programming. It’s also useful when a fault code prevents your car from operating properly, but you don’t have an OBD reader handy to clear the codes. 

There are a few ways to go about doing that, but in this article, we’ll quickly run through the main ECU reset types and discuss the simplest one there is – resetting your ECU with OBDeleven.


Defining ECU


The acronym ECU can also refer to the engine control unit, but an electronic control unit is basically the same as a control unit. While ECU and CU are, in essence, the same thing, to avoid confusion, we’ll continue this article with the term control unit.  

A control unit is a device that basically controls all the electronic features of your car, like cabin temperature or fuel injections. And, of course, different vehicles have a different number of control units. Typically, each unit is responsible for specific functions. However, there are also cases of one control unit controlling multiple car functions.   


Why and when do you need to reset control units?   


There can be many reasons to reset control units. But the most popular one by far is resetting after activating new features. For example, if you like to get hands-deep into your car and code functions yourself, you might find that they sometimes don’t work properly. In this case, resetting your control unit might take care of this problem.  

Think of it like having sudden connectivity problems with your WiFi. You then switch your internet router off and on again to reboot it. In most cases, this method works like a charm.
 
Vehicle control units
 

Control unit reset types


As we mentioned before, there are several ways to reset your car’s control units. The most common reset types are “Key Off On Reset,” “Hard Reset,” and “Soft Reset.” Let’s look over each of them in a bit more detail. 
 
Hard Reset

The hard reset is basically the same as disconnecting power from the control unit. This could be removing your car battery or power source and connecting it again. Once you do that, this initiates a reset process during which your control unit resets.  
Key Off On Reset  

To put it simply, this method involves turning the ignition off, removing the key, and then turning the ignition back on again. Basically, when you turn off the ignition, control units won’t power down immediately – it’ll first store all the data in the Non-volatile memory of the processor and then de-initialize all the programs. Then it’ll go into power down mode without losing any data. Finally, when you’ll turn on the ignition, it’ll follow the same process but in reverse, resetting the control units.  

Soft Reset 

In the most basic sense, it’s the same as turning the ignition off and waiting until the car goes to standby mode. The soft reset is equivalent to restarting your main application program. This means that your stack pointer of the microcontroller will point to the address of the main function. In essence, a soft reset is an application software it’ll restart a control unit immediately. This is a very common reset functionality that's normally used to restart the control units.  


OBDeleven One-Click Apps


If you’re someone who’s looking to save time, money, and wants to have an overall better user experience when dealing with your car, our One-Click Apps are for you. Simply put, our pre-made coding applications do a lot of the manual work for you – and this includes control unit reset. The reset function is already pre-programmed in the app.  

For example, when you change the multimedia startup logo with a dedicated One-Click App, your multimedia shuts down and then powers back up again automatically. This allows the application to properly initiate and continue working.
 
Note: You can find One-Click Apps available for your car on our Supported vehicles page.
 

How to reset ECU with OBDeleven? 

To easily perform an ECU reset with OBDeleven, all you need to do is connect your device to your vehicle's OBD2 port and open the OBDeleven VAG mobile app. Once you have done this, navigate to the control unit list and select the one you want to reset. Then open the “Reset” tab, select the reset type, and confirm your choice by tapping the “Reset” button. That's it – you're done. 
 
OBDeleven diagnostic app screenshot with highlighted "Reset" feature tab. OBDeleven "Reset" feature
 

How to reset ECU without scanner? 

Sometimes, you may find yourself in a situation where you need to reset the ECU but don't have an OBD scanner handy. For example, a trouble code could prevent the engine from starting or even cause the car's wheels to lock up. This often occurs to prevent further damage to your car. But there are times when restoring functionality, even temporarily, is a must. 
  
In such cases, simply turning the ignition off and back on can help, but for more serious issues, this may not be enough, and you may need to perform a hard reset. The easiest way to do this without an OBD scanner is to disconnect the car's negative battery terminal, wait at least 10 seconds, and reconnect it. 
 
Unlike using an OBD scanner, this method doesn't allow you to choose which control unit to reset. This could cause your car's clock to reset, the language to change, or warning lights to appear on the dashboard. It may also result in the loss of some calibrations, such as power windows or power steering. In rare cases, your multimedia system may enter component protection mode and request a PIN code to restore its functionality. 
 
It's important to note that this method won't fix the underlying problem; it will only disable the fault code for a short period. So, you should only use it as a temporary solution, for example, to get the vehicle to a tow truck or the nearest repair shop. 
 

To sum up

Working with your car can be a bit overwhelming at times. But with proper knowledge and patience, you can achieve great results. So, the next time you activate certain functions on your car, and they don’t work, or you don’t have an OBD reader to clear faults, try resetting the control units. It's a simple step that can often solve your problem. 
 
Get OBDeleven diagnostic tool
 
 
Disclaimer: Advice, how-to guides, and car care tips on our blog are intended as helpful resources for general maintenance and repairs. While we strive for accuracy, the information is provided to the best of our knowledge and should be used at your own discretion and risk.

Always refer to your vehicle's owner's manual or consult a certified mechanic for specific repair details and safety procedures.