Carpokes Porsche Forum

I had this warning on my dash before I replaced the battery - "Engine Control Fault possible drive on", and I figured it would dissappear after I replaced the battery but it didn't. Is this something I need to be concerned about and how do I clear it?

My suggestion would be to try to get a read on whatever fault codes there are. That's at least a start. And even though it says that driving is possible, I'd want it checked sooner rather than later to make sure something else more serious wasn't about to occur.

This is what the the code reader showed.
Interesting as I left O'Reillys the warning dissappeared. Went over to the dealership on another issue and they didn't have an answer as to why the warning disappeared but he did say to keep an eye on it.

bcgreen wrote: Fri Nov 24, 2023 6:09 pm This is what the the code reader showed.

20231124_141441.jpg

Interesting as I left O'Reillys the warning dissappeared. Went over to the dealership on another issue and they didn't have an answer as to why the warning disappeared but he did say to keep an eye on it.

Glad it went away and that you checked with the dealership. Hoping the warning stays away!

In case it returns, I searched "DTC Porsche p0421" and there were several responses mostly centering around the catalytic convertor and/or the O2 sensor on that bank. One response "This code pops up when the powertrain control module detects a problem with the warm-up catalytic converter or when there’s a bad oxygen sensor that’s affecting the cat-con’s operation."

Doesn't seem too serious nor that uncommon and also probably a relatively easy fix. Maybe not too expensive either.

If it is a sensor it has been an easy diy for me on multiple cars I've owned in the past, I don't know about the Boxster though.