General Guide for Chiptuning and working safe with ECUs

[elisxnasa]

Guide for Chiptuning and working safe with ECUs

In this short guide I will tell you about my faults and the bad things that can happen during the process of remapping an ECU, even when done by a pro, and how to make sure that you won’t brick or break any ECUs.
I wrote this because when I first started I couldn't find a lot of information well structured in a place about working with ECUs
If you’re a begginer please read this before starting to write any file onto a car’s ecu.
Hope this guide will help in your journey of ECU remapping.

The tree golden rules when doing a remap on a car are the following:

1. Always, when flashing a file to a car via the OBD port, make sure you connect a strong battery charger or a voltage stabiliser to the car and that the battery voltage never drops below 12v. If it drops below 12V during the writing process you risk a lot to brick the ecu, and not being able to easily recover it. This is one of the most common mistakes and it could end up costing you a lot of $$.

2. Before starting to work on a car, make some research about that ecu. It could save you from a very bad day. Google is your best friend. Search for others that worked with that ecu and if they encountered any problems with it. Don’t forget, there are ECUs that can break even if you do everything right, you should avoid them and not take the risk. One example is the Opel / Vauxhall Bosch ME 7.6.2 .

3. If you are going to flash on the car a pre-made file and not a custom edited file, previously read from that particular car, you should double check for the SW (software) and HW (hardware) numbers of the ECU you’re working with to 100% match with the ones of the ecu that file was made for. If they don’t match and you flash the file, you’re gonna 100% brick the ecu and the car won’t start.

Extra: Make sure that your laptop's battery is well or fully charged, and while flashing, put the laptop and the tool in one place and try not to touch them until the writing is finished. You don't want to accidentally move or unplug a cable that could interrupt the writing process.

Remember! When an ecu gets bricked, sometimes it’s very hard to recover it. Keep in mind that if it’s bricked, you lose communications with the ecu via the OBD port, and it becomes unresponsive. In most of the cases, your flashing tool will be able to recover it through it’s recovery mode, but don’t rely on it. You want to avoid as much as possible bricking an ECU. It’s better to be safe than sorry when you’ll find out that recovery mode won’t work.

INFO AND TIPS

Checksums:

Checksums are blocks of data placed in the file stored on the ECU with the purpose of checking that the data integrity was not afected and that the file is complete.
When you modify something in the file, your checksum needs to be recalculated in order to make the file valid for the ECU. Most flashing / tuning tools will calculate the checksum automatically for you.
When you turn the ignition on, ECUs check if the Checksum of the file is ok, and if the checksum of the file is invalid, the ECU shuts itself down to protect the rest of the car from harm. When that happens, your ecu is Bricked and it becomes unresponsive.
The original and most popular tuning / flashing tools will do the checksum automatically for you so there is no need to worry, but also, they're very expensive.
The problem rises while using clone tools. Clone tools will do the checksum automatically for you too, but sometimes they fail to correct it properly, and when that happens, they write your file with the checksum wrong, thing that will again, Brick your ECU. In order to avoid playing the lottery with clone tools, the best option is to correct the checksum manually with the software that you used to edit the file, (WinOLS, ECM Titanium, etc..), or if you're not the one editing the file, ask your tuner to correct the checksum for you. This way you minimize the risk of breaking your ECU.

TProt:

Tprot stands for Tuner Protection. It's a software feature on newer ECU's like EDC17 to prevent people from tuning they're own ECUs. If you don't fully understand working with Tprot ECUs make yourself a favor and don't work on any EDC17 and other Tprot ECUs before you gain some experience on some scrap ones. You can't read Tprot ECUs via OBD, you have to open them and connect to them on bench via the TriCore protocol. I highly recommend you not to work on any cars with Tprot ECUs before practicing on some scrap ones first.

Cars and ECUs to avoid:

The following list is only my personal experience, but it's your choice if you still want to work with these ECUs.
I find those as some high-risk ECUs and I like to stay away from them.
-BOSCH ME 7.6.2 (Opel/Vauxhall) 50% chance of bricking it even with the best tools and perfect files.
-Magneti Marelli ECUs
-Volvo
-Land Rover / Range Rover
-Toyota
-Mitsubishi
There are models from this list that you can flash without problems. Just make your research on the specific model before.

I hope this guide will help you guys to stay away from potential bricking disasters and bad days.

[giannhs2302]

nice post
I want to add that if you have the possibility, make a backup of the ecu to be sure that you can restore it!!!