2020 Hyundai loses vacuum when sitting after first service

Hey guys,

I financed myself a 2020 Hyundai Elantra Preferred model back a few weeks before valentine’s day. Since then it has been fantastic.

The issue I am running into now is that since I took it to a Hyundai Dealership here in Toronto for its first service, now the brake system loses its vacuum over a few hours (which never once happened before on this vehicle or the previous two); and I sometimes hear either a slight knocking from the front of the cat when idling that goes away after a few seconds, as well as sometimes a rattling from the front when going over a bump in the road.

The braking system seems to function like normal once the engine is started and the vacuum restored, but who really knows for sure until it potentially fails.

I’m taking it back today at their request to have it looked at again. But it has me concerned as it’s my first NEW vehicle and these things only began immediately the next day after the service. The vehicle only has 5600 kilometers on it, so j seriously doubt there is a defect with the vehicle.

As a first time new car owner, is there anything I should learn about this kind of situation?

Yes there is . Look in the owners manual for Corporate contact numbers in case the dealer can’t solve the problem . The second thing is you don’t try and fix it yourself or take it to anyone besides a dealer while this problem is under warranty.


Also, make you you keep all records. For example, if they say they couldn’t find a problem, make sure that’s in writing. There should be something for every time you take it in to the dealer.


I took it over and he said “That is strange that it is still happening”

He told me to come back tomorrow so the guy that did the first service can inspect it and let us know if he noticed anything that could be causing it.

Because… he would rather have not told me when he noticed it in the first place?..

I’m going to blow it off and make and appointment at the dealership I purchased it from. I’m getting some bad vibes from this place; even with their good reviews

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