Lupo 3L intermittent limp mode

Good Morning All,

I have been having an intermittent limp mode problem with my Lupo 3L. Sometimes it will struggle to reach 120kmh on the autobahn. if i turn it off and on again it normally fixes it. I scanned it with VCDS and got codes 17964 P1556 - Charge pressure control - Negative deviation. I belive this is called the N75 valve. I ordered one on ebay that i hope is compatible . It stated part number 1H0906627A which i think is correct.

When i fitted it yesterday it made the car a lot worse, it wouldnt even get upto 80kmh. I realised there are two very similar looking devices in the engine bay. Please see attached image. I changed the one on the right. Can someone identify what each one does so i know if i changed the right one. Also, when i fit the new N75 does it require any programming or basic setting?

Cheers

Kieran


DSC_0401.JPG
 
The valve to the right is the N75. Is the one you bought a new N75 or secondhand? Measure the resistance across the contacts of the valve. It should be between 14 and 20 ohms. The fault is more likely due to gummed up vanes on the turbo. You can only clean them by removing and taking apart the turbo. Cleaning details here:

http://www.a2oc.net/forum/showthread.php?22534-VNT-Turbo-De-Coke

After mechanically removing most of the muck, I clean the turbine half of the turbo (only) in a heated ultrasonic cleaner using washing soda and water. This part does not include the bearings.

Don't try cleaning the turbo by sraying oven cleaner (or the equivalent) into it without dismantling the turbo; it will wreck the bearings!

RAB
 
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