Sprays or cleaners don't work. The EGR valve has a matrix of liquid cooled tubes running through it and each is formed into a triangular cross section. The bore of these is about 5mm down the middle. These get completely blocked with very hard-packed carbon. Because there's no flow, any cleaner cannot penetrate. I have successfully dismantled valves and cleaned out the tubes using a combination of Mr Muscle oven cleaner and mechanical methods. The problem is that there's also a motorized valve that uses a plastic gear which can strip teeth due to the valve sticking. There's also a small ball race that can seize. The ball race is a standard part, but the gear needs replacing with an aftermarket new part or one from a good donor valve if faulty.

I've got replacement time down to under 2 hours, but that's with a 2WD. You have added complexity and time with 4WD.

It's illegal to disable any part of the emissions system.

The EA189 fix increases load on the EGR valve, DPF and injectors. Skoda offered an extended warranty on these parts after the fix was applied as a goodwill gesture.

 

Sprays or cleaners don't work. The EGR valve has a matrix of liquid cooled tubes running through it and each is formed into a triangular cross section. The bore of these is about 5mm down the middle. These get completely blocked with very hard-packed carbon. Because there's no flow, any cleaner cannot penetrate. I have successfully dismantled valves and cleaned out the tubes using a combination of Mr Muscle oven cleaner and mechanical methods. The problem is that there's also a motorized valve that uses a plastic gear which can strip teeth due to the valve sticking. There's also a small ball race that can seize. The ball race is a standard part, but the gear needs replacing with an aftermarket new part or one from a good donor valve if faulty.

I've got replacement time down to under 2 hours, but that's with a 2WD. You have added complexity and time with 4WD.

It's illegal to disable any part of the emissions system.

The EA189 fix increases load on the EGR valve, DPF and injectors. Skoda offered an extended warranty on these parts after the fix was applied as a goodwill gesture.

Thank you so much for this! I think my approach will be
a) replace the EGR valve
b) perhaps I can reduce future wear/tear on parts by using Premium diesel/additive...+/- reverse the EA189 fix when my wallet has recovered from (a)... is that legal, as it's not disabling anything? I've seen plenty of Yeti owners either have refused the fix or reversed it...

 

Reversing the "fix" is perfectly legal. Do it and don't worry about it.