moDiag - Frequently Asked Questions


F: Is it possible to connect to older cars with moDiag?

A: moDiag is an OBD-2 scan software. This means moDiag uses the standardized and manufacturer independent protocols, which have been implemented for emission related diagnostics. These protocols have been implemented in the EU for cars with Otto engines from the year 2000/2001 on (Diesel 2003/2004).

Because OBD-2 standards where originally implemented in the USA in cars (Otto engines) from the year 1996 on, there are some vehicles in the EU (those which have been exported to the USA), which already use OBD-2 although they have been built before 2000.

But generally spoken: In the EU Otto engines before 2000/2001 and Diesel before 2003/2004 do not have OBD-2 - this means: moDiag is not suited for them! But: no rule without exception!

You can find a (incomplete) list of OBD-2 compatible cars under the following link:

 F: When connecting, moDiag reports „No OBD compliant ECU found“ – what can I do?

A: There are a few reasons for this

  1. Vehicle is not OBD-2 compliant
    1. Even if the car has already the OBD-2-connector (DLC) built in - this does not mean, that the OBD-2-protocols are implemented into the cars ECU! Check the built year of the car! See the item above!

  2. ECU went into time-out
    1. Some ECUs go into time-out, when the interface is connected and not immediately a communication occurs. Proceed as follows: Start moDiag on your laptop. Connect the Interface to the laptop. At the car turn ignition to on or start the engine. Connect the interface to the car. In moDiag click on "Connect" immediately.

  3. You have chossen the wrong protocol in moDiag
    1. By default, moDiag uses the automatic protocol scan of the OBD-interface ("Auto-1"). This means the interface is forced to search for the right protocol. But you also can choose a certain protocol prior to the click on "Connect" - in this case moDiag tries to connect only with this protocol. If the ECU in the car does not "speak" this protocol, the above mentioned message will occur.

 F: Can I reset the service indicator light with moDiag?

A: No! OBD-2 protocols are standardized for "emmisions related" diagnostics. The service indicator is not emmisions related! It is a function which is implemented by the manufacturer. And every manufacturer has a different way to reset it.

F: Can I read/erase trouble codes of Anti-Lock-Brake system (Climate Control, Airbag...)?

A: No! These are not "emmissions related" systems. Therefor for these systems no standardized communication protocols exist! Every manufacturer has his own way of communication to these systems!

F: But the workshop also uses the OBD-2-connector to communicate with the Anti-Lock-Brake system (Climate control; Airbag...)?

A: The OBD-2 connector has more pins than neccessary for OBD-2-diagnostics. The manufacturer specific testers of the work shop are using other pins of the connector and - more important - different and manufaturer specific communication protocols.

F: Why can I read only the "Engine Speed" ("Vehicle Speed"...) with moDiag and not more?

A: Because the manufacturer did not allow to read more sensors over OBD-2! Like all OBD-2 scan tools, at the start of a communication moDiag will request the list of supported parameters (PIDs) from the vehicle. Based on the response to this request, moDiag builds the sensor table. The OBD-2 standards contain a lot of possible parameters, BUT most of these parameters are optional, which means, the car manufacturer is not obliged to report these values via OBD-2! Especially cars built in the first years of OBD-2 in the EU often report only a few parameters. There are even some cars which report an empty parameter table!
HINT: In such case it could help to uncheck the checkbox "Read only supported sensors" in moDiag. Now the table will be rebuild and will show all possible parameters. Now you can check these parameters and moDiag will request them from the car. But in most cases the response of the car will be "Error" or nothing!

LPG adjustment with moDiag professional

F: Will moDiag work together with all LPG softwares?

A: Yes, moDiag will work with all Windows-based LGG softwares!

You can store up to 32 different LPG softwares into moDiag. The software will then automatically be started by moDiag, when you start to an LPG adjustment drive cycle.

F: Do I still need the LPG adjustment software / the interface to the LPG kit?

A: Yes! moDiag is just an OBD-2 scan software and communicates to the Engines Control Unit of the car - not to the LPG kit! For the communication/adjustment of the LPG kit you will need the software and interface of the LPG kit´s manufacturer!