These fault codes range from ‘a button got stuck once in the last 200 ignition cycles’ to ‘internal fault in a module’. If a module is to be replaced it pretty much always will have a fault code (DTC) set that will indicate the need for replacement OR there is a Technical Journal (TJ) from Volvo that gives a reason to replace a module because of reason X, Y or Z.
Ask very pointedly what code(s) their ‘diagnostic process’ has revealed that mean the KVM and antenna have to be replaced.
Is this under warranty or are you paying for all of this?
I get the impression they are just throwing parts at it until the issue goes away. So similar to your impression.
The KVM can not easily be swapped as it holds the key data for the vehicle. So a known good but used one will not work with your keys as it doesn’t know your keys.
It would need to be programmed to work with your vehicle.
Again let me point out that even if the KVM was faulty it should not cause airbag, power steering and brake system issues.
There have been issues with the antennas for the keyless entry part of the system. Volvo has several TJs out that cover both the door handles and the central antenna in the headliner.
But in these cases it would cause issues that are limited to:
- keyless entry not working
- keyless entry / remote range being severly limited
- car key not being recognized when kept in the pocket of clothing
- car indicating that the key has left the vehicle even if key is still inside the vehicle (if vehicle is switched on)
- car indicated that no key is present in the vehicle and that no engine start is permitted
For reference and reference only, as they do not directly apply to model year 2015.5, are two TJs that Volvo has on that topic. As S60 and V60 are similar the same topics apply in this case:
https://static.nhtsa.gov/odi/tsbs/2018/MC-10157945-9999.pdf
https://static.nhtsa.gov/odi/tsbs/2018/MC-10157879-9999.pdf
For further information just know that the KVM is on a different CAN bus network that the modules that are responsible for the airbags, the brakes and the power steering.
KVM is on the medium speed (also called intermediate speed) CAN bus.
EPS (power steering), SRS (airbags) and BCM (brakes) are on the high speed CAN bus.
Side note:
A previous poster also said that there might be an issue with the BCM. I believe that poster meant BCM as in Body Control Module but Volvo does not use that term, they call it CEM as in Central Electronic Modul. The Volvo term for BCM is Brake Control Module. Hope this avoids potential confusion.
On the push button part.
There is no traditional ignition that can be turned using a key, the only physical key barrel is the one in the drivers door.
All S60 / V60 on the P3 platform have push button start. There is a slot in the dashboard to the right of the instrument cluster into which the key is to be inserted.
On vehicles with keyless start, which applies in your case, the key doesn’t have to be inserted.
Can you if possible provide the exact parts that were replaced by the dealership during previous visits?
And what they wrote as the reason for replacement?