Fault Code - Loss of Power

Mr Cellotape

AKA Mr Ribbed
May 9, 2006
Warwickshire once.
Hi all,
The wife had a loss of power today in the Cupra TDI and I wondered if anyone would know what the fault code means?

17965 P1557 036

Boost pressure regulation control limit exceeded
No image in the display.

I asked if there was loads of smoke and she said she didn't notice as I thought a boost pipe had popped of.

She said this has happened before. Once about a year ago before it had a service........fine since then.

When she drove it after it was put on Vag com it drove normally.

The dealer has said they suspect sticking variable vanes on the turbo and are talking about replacing the turbo. I'm not so sure as it's due its service in two weeks and the service may cure whatever it is.

Any thoughts anyone?
Jan 11, 2005
If you have vag-com, to check the vanes start your engine and go into Engine 01 then basic settings 04 and enter number "011", click on "GO".

The revs should rise to about 1400rpm and either "ON or "OFF" will be displayed in position 2, swapping every 15 seconds, (glow plug light will be flashing and you'll get a beeping whilst it does it) you should be able to see the actuator lever moving from under the car. If it isn't moving, try tapping with a screwdriver & spraying WD40 but only when the engine is COLD. If there is a scraping noise happening when alternating between ON & OFF, I'd say turbo vanes sticking. Just leave the test running for 20 minutes to try and free them up.

Alternatively when the engine is warm, gently raise the revs when driving to over 4000rpm for an extended period of a mile or longer if you can. This will get the temperature up in the turbo and will burn some of the soot build up off. After you have done this you can drive normally (making sure you are coming on & off boost). That should dislodge the now loosened hot soot and blow it out. Remember to let the turbo cool with the engine running when you stop though.
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