Welcome to the Delphi Euro 5 Diagnostic Portal. This site is solely intended for users of the Delphi Euro 5 Diagnostic VCI. The portal will guide you to the vehicle manufacturers web sites in order for you to access diagnostics information and software updates using your Euro 5 VCI. From this site you can also find the latest firmware updates and drivers for your hardware.


Sometimes software is updated to improve fuel economy, exhausts or to fix separate faults in the original software. Updating the software in an ECU is often a proactive action to prevent faults from appearing. Updating the software in the ECU is also called flash reprogramming or software download.

For the OEM workshop the software download is relatively easy and straight forward because the mechanic has access to an adapted tool connected directly to the OEM’s server. For the independent workshop this has previously been impossible to perform and they have been forced to take the vehicle to an OEM workshop.

Euro 5 – Software download

According to the Euro 5 legislation, which was implemented in September 2009, the independent workshop has been given the possibility to perform what was earlier limited to the OEM workshop.

With a generic interface anyone who has got a login at the vehicle manufacturer can perform a software download and update ECUs with the same result as an OEM tool. This works differently for each vehicle manufacturer. It can be an all web based solutions or in other cases there is a PC-software which connects the vehicle to the OEM server. This software can either be downloaded or distributed via CD or DVD. Generally it is a fact that it is only online solutions available. The user/workshop cannot download ECU software to the computer and then later download it to the ECU.

Software download in Euro5 regulations is performed via a web portal or a PC application which is connected to the internet and a VCI (Vehicle Communication Interface), which is connected between the vehicle and the computer. The VCI must be built according to certain standards to be a Euro 5 Pass Thru VCI. There are standards both in ISO (International Organization for Standardization) and SAE (Society of Automotive Engineers). By converting the data that is collected from the internet the VCI makes it possible for the vehicle to communicate to the vehicle manufacturers web portals. There are a number of valid communication protocols according to the standards. The protocol used in the specific case is controlled by the car, the VCI and the web portal.

Fees for licenses, login and software are different depending on vehicle manufacturer. In some cases there are yearly licenses and in some cases you will pay a fee for a certain time of use. For example 1 hour, 1 day or 1 month when you have access to the information on the web portal. For some brands you pay for the specific function or software to be downloaded. The coverage of functionality and depth varies for the different vehicle manufacturers. In some cases there is only the legislated information and functionality available, and in other cases you will find information and functionalities for older vehicles and also with functions such as fault code reading, view real time data and adjustments.

To perform a software download it requires both computer skills and experience. The mechanic will handle a computer, the VCI and the application for software download. There is also a requirement for a high speed internet connection.

Non-compatible VCI

Due to the fact that the Euro 5 Pass Thru device (VCI) is determined by certain standards, all devices should be the same, but the reality looks a bit different. There are devices that are not fully compatible and therefore do not work with all vehicle brands. It is important that you make sure you have a compatible VCI. The vehicle manufacturers do not sell their own tool for software download, but they are forced to test and validate at least one independent VCI. These are normally listed on the web portals. The Delphi Euro 5 VCI is built according to the standard and has extended functionality to be able to communicate also with vehicles not regulated by Euro 5.

Is the update required?

It is important to find out if the update is required before downloading new software to the ECU. Information is often to be found on the vehicle manufacturer’s web portals. In some cases you have to connect the vehicle and maybe pay the fee for a certain time period. This means that you might have to pay just to find out that there is no new update available.

Euro 5 Pass Thru

It is really important that the voltage supply does not drop below 12 volts during the entire process. Some operations might start power consuming components such as fans, pumps etc. which causes the voltage to drop. To ensure that the voltage is correct it is recommended to use a high power battery charger with voltage surveillance. If the voltage drops the software download might fail and in worst case the ECU might be damaged.

To become familiar with Euro 5 Pass Thru we recommend that you start with one brand and a vehicle that you have good access to, before downloading to a customer vehicle. Take your time and follow the instructions on the vehicle manufacturer web portals. If you have questions how to move on, call the vehicle manufacturers support line. Information and support number is found on the web portal.

Euro 5 Pass Thru requires a computer with internet connection and the operator should have experience in working with computers and the internet.

When you offer this service to your clients there are a few things you should be aware of and in some cases inform the customer. Software download is a service that cannot be reversed. When new software has been downloaded into a vehicle, there is no way to get the previous software back. It is possible that a software download can change the driving characteristics. Engine idle might rise or reduce; gear shifting in an automatic gearbox may behave differently. This is not frequently the case, but it is important to inform the customer before taking action.

The time to perform a software download varies for different brands and models. In some cases the entire software in the ECU is exchanged and in some multiple ECUs are updated, in sequence or simultaneously. The average time for a software download is 20 minutes, but the fastest is less than a minute and it might take many hours to perform a software download.

Software download might fail due to faults in the wiring harness or faults in the ECU. Other cause can be voltage drop during download. If the download fails, restart and make sure the pre-conditions are fulfilled and that all instructions are followed. If this does not help, contact the vehicle manufacturer support for Euro 5 Pass Thru programming.