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VW Check Engine Light - Drove Through Water

Hi all! This is my first post on this forum so hopefully I get some good feedback.

On Thursday after the downpour in the Boston area, I was on my way home and drove through a flooded section of the road (approximately 15’ long). I used to drive an Audi Quattro and this was never a problem but now I drive a Golf and I’m afraid I may had made a big mistake! I plowed through it with no problems (no smoke, stalling, sounds, check engine light, etc.) and was home about 5 minutes later. About half an hour when I got back into the car, I noticed that the check engine light was on! I imagine I did damage when I drove through the water but I am not sure that the two are related.

This was Thursday and I’ve been driving it around fine all weekend with the check engine light on. My mechanic is open on Saturdays and I plan on dropping off then for an official diagnosis but I was curious if anyone could tell me if they think I’ve really screwed things up. ;-( I guess I’m hopeful that I may have just flooded the engine but that it will dry itself out and the light will go off. Or am I just wishful thinking?

Any feedback would be appreciated. Thanks!

If you’re lucky the light will go off after things dry out, but if it stays on you should have it checked out. The light may be unrelated to the water.

A guess only, but catalytic converters operate efficiently at a high temp. Perhaps the water cooled the converter and made it less effective and it threw a code. If this is the case the light should reset itself in a few days, or if your mechanic reads and clears any codes it should not recur. Perhaps a sensor was damaged by the water and needs to be replaced.

I can’t directly answer your question, but I can point out that if you “flooded the engine”, you’d now be shopping for a replacement engine, as water doesn’t compress and all sorts of things would break.

I think that most likely problem would be a bad oxygen sensor located downstrem of the catalytic converter. The temperature shock from being submerged could easily damage it since is normally very hot. Good luck.