Throttle position discrepancy

I have an 03 2.0 dti Signum, and the engine management light keeps coming on
(3 times in the last week), and the engine switching to limp home mode
(until I turn the ignition off and on again). I took it to the local garage
to get teh codes read, and they said it gave a throttle position discrepancy
code. He said their kit did not go into detail or carry out any kind of
testing, and a VX dealer would be able to. There are several things it
could be, and his only way of diagnosing would be to throw expensive parts
at it one at a time.

Is there a common fault on these engines? I have noticed a distinct lag
(like turbo lag) recently, and am thinking it is either the actuator
becoming weak, or the throttle being sticky/gummed up, just like my old
favourite the idle control valve off my R reg veccy. Is stickyness usually
the case, or is it a replacement job (I know VX replace ICV rather than
clean them out).

Bob

 

Check your vacuum pipes - 9/10 times the engine man light comes on with
these engines it is a vacuum leak.
Easy check is get someone to start it while you watch the waste gate
actuator move - if it doesn't move you have a major vacuum leak. If it does
move get hold of it ( while engine is running ) and try to push it back - if
it moves easily you have a minor vacuum leak.

 

10/10 - Took it to the VX dealer today. A 2p (£3.50 in VX prices!) 1 inch
long "junction hose" was split, but you can guess the bill was not for 20p.

Bob