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How To Reset Your E.c.u.

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486K views 44 replies 38 participants last post by  rnacua0  
#1 · (Edited by Moderator)
I wrote this article a few years ago in an attempt to dispel the myth that it is not possible to alter the engine control unit`s factory settings.

In fact, the simple procedure outlined below should be performed after every performance mod. (such as fitting a cold air intake) & can even be of benefit if you`ve spent the whole week stuck in commuter traffic jams & want to restore your car's performance for the weekend!

Resetting Your ECU (Engine Control Unit)
Hyundai cars are designed to be driven in all areas of the world, by people of all ages and levels of experience and sophistication. They are set to operate at all altitudes and temperatures and to use fuels of varying octane-rating and purity.
Unsurprisingly, the electronic engine control unit of your vehicle has been pre-set to a one-size-fits-all state of tune. Whilst the ECU has the capacity to adapt to the owners driving style to a certain degree, the base settings are extremely conservative and Hyundai's are famously set to run rich!

Most owners would naturally suppose that this situation is something over which they have no control, but this is not the case.
This document will instruct any owner on how to change the ECU settings of their car, without the alterations being detectable by the Dealership, the Insurance Company, or indeed having any effect on the vehicle's warranty.
The operations described are recommended as a first step after taking over ownership of the car, after carrying out any performance modifications, or after any temporary change in the way the vehicle has been used ( i.e. city-bound use, towing, etc.).

Firstly bring the car to normal operating temperature by driving for 15 minutes or so.
Now open the bonnet and disconnect the earth lead from the battery, ensure this is not touching any part of the bodywork - insulate if necessary - and wait 5 minutes.
Next depress the foot brake for 20 seconds - this will completely discharge the ECU's capacitors via the brake lights.
The next step (to be carried out immediately, while the engine is still warmed-up) is to carefully re-connect the battery earth lead, close the bonnet and now drive the car in a spirited fashion (accelerating rapidly through the gears, full-throttle straights, etc., etc.) for a full 30 minutes. Try to choose a quiet time on the roads for this, (i.e. early on a Sunday morning!).

This period of driving will re-educate your ECU into adopting more aggressive timing curves and alter the fuelling to match. It will also allow the unit to recognise any modifications you have made and to react accordingly.

If, on the other hand, you are not interested in outright performance, but are more concerned with economy and flexibility, use your normal driving style during this 30-minute run!

Over time, the ECU will slowly revert to the factory settings - especially if it is not being driven spiritedly on a regular basis. Accordingly, many owners tend to do this reset monthly, before a track day or even a long run.

Cheers,
Nick. :)
 
#29 ·
Thanks man you made me feel happy :)

I'm living in Kurdistan region, here our gasoline is not good, so the engine of my car is knocking a lot, and stops another time, I was feeling that I have a problem with my car, and my car wasn't acting like earlier !!

but I think your idea will solve my problem :) Thanks a lot
 
#32 ·
Sc lategan

i wrote this article a few years ago in an attempt to dispel the myth that it is not possible to alter the engine control unit`s factory settings.

In fact the simple procedure outlined below should be performed after every performance mod. (such as fitting a cold air intake) & can even be of benefit if you`ve spent the whole week stuck in commuter traffic jams & want to restore your cars performance for the weekend!.

Resetting your ecu (engine control unit)
hyundai cars are designed to be driven in all areas of the world, by people of all ages and levels of experience and sophistication. They are set to operate at all altitudes and temperatures and to use fuels of varying octane-rating and purity.
Unsurprisingly, the electronic engine control unit of your vehicle has been pre-set to a `one-size-fits-all` state of tune. Whilst the ecu has the capacity to adapt to the owners driving-style to a certain degree, the base-settings are extremely conservative and hyundai's are famously set to run rich!

Most owners would naturally suppose that this situation is something over which they have no control, this is not the case.
This document will instruct any owner on how to change the ecu settings of their car, without the alterations being detectable by the dealership, the insurance company, or indeed having any effect on the vehicle's warranty.
The operations described are recommended as a first step after taking over ownership of the car, after carrying out any performance modifications, or after any temporary change in the way the vehicle has been used ( i.e. City-bound use, towing etc.).

Firstly bring the car to normal operating temperature by driving for 15 minutes or so.
Now open the bonnet and disconnect the earth lead from the battery, ensure this is not touching any part of the bodywork - insulate if necessary - and wait 5 minutes.
Next depress the foot brake for 20 seconds - this will completely discharge the ecu's capacitors via the brake lights.
The next step (to be carried out immediately, while the engine is still warmed-up) is to carefully re-connect the battery earth lead, close the bonnet and now drive the car in a spirited fashion (accelerating rapidly through the gears, full-throttle straights etc. Etc.) for a full 30 minutes. Try to choose a quiet time on the roads for this, (i.e. Early on a sunday morning!).

This period of driving will `re-educate` your ecu into adopting more aggressive timing curves and alter the fuelling to match. It will also allow the unit to recognise any modifications you have made and to react accordingly.
If, on the other hand, you are not interested in outright performance, but are more concerned with economy and flexibility, use your normal driving style during this 30-minute run!.

Over time, the ecu will slowly revert to the factory settings......especially if it is not being driven `spiritedly` on a regular basis.
Accordingly, many owners tend to do this reset monthly, or before a track day or even a long run.

Cheers,
nick. :)
i have a hyundai sonata 1998 model excellent condition - but now gearbox problems- car is at gearbox center for gearbox reconditioning. This has been done but still does not change gear when it should, i have been told it is the ecu by the gearbox people but they cannot access the ecu and are going to try an ecu from another sonata like mine - is this normal and why can they not access the ecu???? I paid them a lot of money and still have no car 6 weeks later - who can access this ecu - the agent claims they cant --- where to now?
 
#36 ·
I'm trying to reset my ECU on my Hyundai sonata 2014 to reset the adaptive learning automatic transmission. My decelerating when coasting hasn't been smooth since I bought the car. The last person that owned my car was a highway driver, I drive a lot through residential areas, So my theory is the different driving modes are causing these shifting points to be somewhat jerky. So at least I want to try and reset it. If it's as easy as disconnecting the battery I'd give it a shot.
 
#38 ·
I wrote this article a few years ago in an attempt to dispel the myth that it is not possible to alter the engine control unit`s factory settings.

In fact the simple procedure outlined below should be performed after every performance mod. (such as fitting a cold air intake) & can even be of benefit if you`ve spent the whole week stuck in commuter traffic jams & want to restore your cars performance for the weekend!.

Resetting Your ECU (Engine Control Unit)
Hyundai cars are designed to be driven in all areas of the world, by people of all ages and levels of experience and sophistication. They are set to operate at all altitudes and temperatures and to use fuels of varying octane-rating and purity.
Unsurprisingly, the electronic engine control unit of your vehicle has been pre-set to a `one-size-fits-all` state of tune. Whilst the ECU has the capacity to adapt to the owners driving-style to a certain degree, the base-settings are extremely conservative and Hyundai's are famously set to run rich!

Most owners would naturally suppose that this situation is something over which they have no control, this is not the case.
This document will instruct any owner on how to change the ECU settings of their car, without the alterations being detectable by the Dealership, the Insurance Company, or indeed having any effect on the vehicle's warranty.
The operations described are recommended as a first step after taking over ownership of the car, after carrying out any performance modifications, or after any temporary change in the way the vehicle has been used ( i.e. city-bound use, towing etc.).

Firstly bring the car to normal operating temperature by driving for 15 minutes or so.
Now open the bonnet and disconnect the earth lead from the battery, ensure this is not touching any part of the bodywork - insulate if necessary - and wait 5 minutes.
Next depress the foot brake for 20 seconds - this will completely discharge the ECU's capacitors via the brake lights.
The next step (to be carried out immediately, while the engine is still warmed-up) is to carefully re-connect the battery earth lead, close the bonnet and now drive the car in a spirited fashion (accelerating rapidly through the gears, full-throttle straights etc. etc.) for a full 30 minutes. Try to choose a quiet time on the roads for this, (i.e. early on a Sunday morning!).

This period of driving will `re-educate` your ECU into adopting more aggressive timing curves and alter the fuelling to match. It will also allow the unit to recognise any modifications you have made and to react accordingly.
If, on the other hand, you are not interested in outright performance, but are more concerned with economy and flexibility, use your normal driving style during this 30-minute run!.

Over time, the ECU will slowly revert to the factory settings......especially if it is not being driven `spiritedly` on a regular basis.
Accordingly, many owners tend to do this reset monthly, or before a track day or even a long run.

Cheers,
Nick. :)
I had my Aamco guy do this and several computer checks but the PCM code shows a malfunction. Should get a new computer or buy one off Ebay or something. Ineed to retest for my smog cert.
 
#40 ·
It is unlikely that the problem with your car is a bad PCM. I recommend that you post a new thread on the forum for your model car with the trouble code (in Pxxxx format such as P0304) for help in solving the problem that is causing the trouble code. Good luck :). Please fill in the info about your car, it helps if we know what kind of car you have!
 
#43 ·
Heya - great info - I just wanted to ask a specific question - I have a 1996 Hyundai coupe RD generation 1 auto- which was originally a 2.0litre engine capacity , but due to transmission issue ( caused by RAC 🤬 but anyway lol - then engine issues , massive leaks and missing parts when they gave car back to me ) I had to change the transmission and engine, and because there were never many in aus, parts are becoming increasingly difficult to find over here, and I had to replace with a 1.8 litre engine from same car still DOHC 16v as that’s the only one which would fit . ( found it after 2 years of waiting) ... anyway my question is about the ECU as it is the original one which is for a 2.0l engine - would the ecu just adapt and learn what’s required now that it’s controlling a 1.8l , or would it be setting incorrect levels for the fuel/air mixture etc - is there any other things that could be affected / set do fferent for a 2.0l / 1.8l ? Thanks !