Skoda Octavia Bypass Valve and Overheating Issue

Overheating and a bypass valve error on an Octavia… sounds familiar. I had a similar issue with mine. Is it a petrol engine? Check the vacuum system. A leak there can cause all sorts of weirdness with the engine management. It could be that the bypass valve itself is fine, but it's reacting to incorrect readings from elsewhere. When the vacuum isn't right, it can affect things like fuel efficiency and even cause engine stalling sometimes. Power loss too. I'd start there before assuming the worst about the valve itself. Do you have access to a scan tool that shows live data?

Thanks for the quick reply! Yes, it's a gasoline engine. I've checked the error memory with an OBD scanner and there is indeed an error related to the bypass valve. What exactly should I be looking for when checking the vacuum system? Any specific hoses or connections that are prone to leaking? I'm comfortable doing some basic troubleshooting myself, but I don't want to mess anything up even more. And what do you mean by 'live data'? What am I looking for?

Okay, "live data" from the scan tool refers to real-time readings from various sensors in the engine. You'd be looking at things like manifold pressure, throttle position, and airflow. If you see erratic readings, especially related to pressure, that's a good indication of a vacuum leak. As for specific hoses, check all the small rubber hoses connected to the intake manifold and the bypass valve itself. Give them a wiggle and look for cracks or brittleness. Honestly, if you're seeing overheating, I'd strongly recommend taking it to a workshop. Vacuum leaks can be tricky to pinpoint without proper equipment, and overheating can cause serious engine damage. It's probably best to leave this for the experts.

Just a heads-up, the Octavia went to the workshop, and you were spot on! The bypass valve error was a 'ghost' – something else was causing it. They checked the vacuum system and found a small leak in one of the hoses connected to the exhaust system. That was throwing everything off, causing a consequential error that was triggering the bypass valve malfunction warning and eventually the engine overheating. Crazy! They fixed the hose. The repair was covered under warranty so no cost to me! Thanks a bunch for the help!