EPC light - no code - Went away after 5 mins

Was cruising along in 6th accelerating to about 110mph part throttle. Then the car chimed on the screen "Engine Workshop Fault" and the orange EPC light showed.

I had my accessport plugged in so did a fault scan on the fly and no codes showed up?

I then turned the car off and on again and regained boost as it had gone limp, 5 mins later the light went away and still no codes.

What could it have been? I felt no engine issues before the light went on.

I can't provide much help here, but I've had this exact same problem on my 2009 TSI many times over the years so maybe we can work together to figure it out.

I've had this happen to me both a few seconds after startup or while cruising on the highway. It's still driveable but RPMs are limited to 2.5k (maybe 2k, I can't remember) so you can really only get up to 67mph or so. Turning the car off and on usually makes it go away, but sometimes it sticks around for a few minutes or through several restarts. There have been bad periods where it'll pop every time I start the car, and sometimes I'll have to resort to driving for a while in limp mode because it just won't go away.

For the life of me I haven't been able to figure out what's going on. No codes are stored. I had both the dealer and TyrolSport do a diagnosis and they couldn't find anything. I've had the throttle body changed and it didn't help. I purchased this Throttle Body Connector kit, but it looks like it had already been replaced by the previous owner (there was a TSB on the throttle body wiring on certain TSI engines, see here). Now that I have the wiring harness, I might just try replacing it again—although I'm in a good period lately and it's only gone off once in the past few months.

What I've been doing is unplugging the throttle body connector at the front of the engine and spraying it with CRC Quick Dry Electronic Cleaner—it usually goes away after that. But this could be a placebo effect, since it happens sporadically enough that it could be doing nothing at all.

Probably a different problem but maybe of help! I had a similar situation a few months back in my work van (VW Crafter), it would do what you've described and then it would go back to normal after cycling the ignition, it would come back but only when I was pushing the van to its full speed on a certain stretch of road which had a slight downhill gradient, it turned out to be over boost which was fixed by replacing the turbo!


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Went to my friend who runs a dyno shop with all of the software goodies. He plugged in his VCDS and found a p0234 overboost code. 4000 RPM is exactly where the car tends to go over 22psi and out of the MAP sensor range so I'm guessing its that.