Skoda Karoq bypass valve error and overheating

Interesting issue. A bypass valve malfunction on a diesel, especially a new one, is unusual. Engine overheating is a serious symptom. Before assuming the worst about the bypass valve itself, have you noticed any changes in fuel efficiency or any unusual sounds coming from the exhaust system? Is the engine overheating consistently, or only when idling or during high-speed driving?

Fuel efficiency seems normal, and I haven't noticed any strange noises. The overheating seems to happen more when I'm stuck in traffic. Could a problem somewhere else in the exhaust system, perhaps related to the DPF, cause the bypass valve error and engine overheating?

Given that the overheating occurs primarily in traffic and your fuel efficiency is normal, it's highly likely the bypass valve error is a consequential error. A faulty sensor in the exhaust system, or even a vacuum system leak, could be the root cause. The engine overheating is probably a separate issue related to reduced airflow at low speeds. I had a similar issue with a faulty EGR valve on my old Octavia. I suggest taking it to a workshop; they can perform a thorough diagnostic check to pinpoint the source of the error and address the overheating before it causes further damage.

The dealership confirmed it was a ghost error from a faulty sensor in the exhaust system that triggered the bypass valve error. They cleared the code and checked the vacuum system. Everything seems fine. No charge!