Hello Skoda owners,

2 times I have received exhaust flap wrong position error during cold days. Did proper maintenance on this, and re-installed the flap motor underneath of my car.

Then connected CarScanner ELM , wanted to delete DTC-s and perform the flap adaptation procedure. Erase DTC-s Command was send and some minutes later received: U0100 error- Data bus, engine control module(ECM) A- no communication.

Check Engine Light(CEL) is now on, car starts normally and drives without noticeable problems.

What I have tried so far, to remove CEL:

1) Battery was fully charged, before connecting CarScanner.

2) Performed 10 min battery disconnect , CEL is still on.

3) Performed 4 km test drive, CEL is still on.

4) Checked the fuses in both fuse boxes, Fuses were OK.

4) Some ECU-s I can still connect with CarScanner, understanding that CAN network is still OK.

Any ideas how to diagnose further more? More hands-on tests to try on in similar cases?

Thanks in advance,

Olari

Olari, have you checked the flap under the car again, that it's fitted correctly and any connections and wires are clean, secure and protected, checked connections and wires at other end.

If you are really sure any problem has been sorted then perhaps if you try clearing the code when it's warmer (to see if it returns when it is next colder). Try this after driving more than 4km - but no communication is an error somewhere with the car or CarScanner ELM, is the CarScanner ELM programing fully up to date for your car. Or you could try using a different scan tool but no communication might show again (or it might not).

HTH.

On 06/01/2026 at 16:00, nta16 said:

Olari, have you checked the flap under the car again, that it's fitted correctly and any connections and wires are clean, secure and protected, checked connections and wires at other end.

If you are really sure any problem has been sorted then perhaps if you try clearing the code when it's warmer (to see if it returns when it is next colder). Try this after driving more than 4km - but no communication is an error somewhere with the car or CarScanner ELM, is the CarScanner ELM programing fully up to date for your car. Or you could try using a different scan tool but no communication might show again (or it might not).

HTH.

Thanks NTA16 for your response.

In my specific case Carcanner ELM locked the ECM communication???, when I performed DTC clear command ( First time when something like this has happened).

Positive thing happened in 24h later, when CEL disappeared in dashboard. ECM unlocked itself, after period of time?

//Olari

You have a 2022 care VW added extra gates to lock out scan tools around 2020, SFD does Carcanner ELM cope with this.

It is usually driving the car a distance or a number of cycles or uses where the computer programs decide it no longer needs to post messages and signs of doom. Is your car one that gets over the air updates and one got one by coincidence.

Hopefully you have sorted things just be happy the computer is happy at the moment. 🙂