Can anyone help with these fault codes. My car is a 2000 Tdi 90 agr with high mileage.

5 faults

00668 implausible signal

17552 maf open to ground

17664 engine temp circuit open to ground

17946 engine shutoff solenoid open to ground

17978 engine control module disabled(sporadic)

I have used your search engine and taken the following actions

Renewed air,fuel and oil filters

New maf(bosch)

New temp sender

New relay 109

Egr looks clean inside

The turbo worked after new maf for one journey, no excessive smoke or oil consumption.

Should I try n75 next or am I going in wrong direction.

Have you cleared the faults from the ECU ?

As i'm sure they'll still be shown on a scan, until they are cleared, even if the problem is fixed.

Agreed - deffo clear them (save them first if you can) then see if the errors come back

Thanks guys I'll do that and keep posting

Also definately fit a new N75

Update-

vag-com now showing only 17946 engine shutoff solenoid.

Fitted new n75 £58 vagparts,turbo boost still intermittent.

Any ideas anyone?

Update no2

Have removed Turbo with manifolds for a look.Turbine blades look okay, however there is some play in the bearings, how much play is excessive?.

Should I fit a reconditioned unit or source one from a breakers(very high mileage car). Help much appreciated.

What led you to removing the turbo ?

Lot of effort !

It was a lot of effort Johnny50 but I thought I might find some clues for my intermittent turbo problem in there, I have run out of electrical parts to replace and getting desperate.

It was a lot of effort Johnny50 but I thought I might find some clues for my intermittent turbo problem in there, I have run out of electrical parts to replace and getting desperate.

How many miles has the car done? I had a similar problem with my Golf, and it ended up being the Air Mass Meter. VAG COM never showed a fault code for it. I ended up with a replaced turbo before V-Dub figured out the problem. It's and expensive part just to try though, so maybe "borrow" one off another engine for 2 minutes, or buy a cheapo one from a breakers.

If you mean the MAF sensor, I have already renewed it but thanks anyway. The car has done 178k. I'm going to put the Turbo (which I think is still serviceable)back on with new gaskets and have a very carefull look at all the associated pipework.