Hello everybody.

I've had the exhaust control system and glow plug lights come on recently so when I got the car serviced and cambelt done I asked the garage to plug in and tell me what the problem was.

Skoda diagnosed what they referred to as a "turbo boost actuator fault". This is apparently relating to the actuator which controls the position of the vanes in the turbo. The technician advised this is most likely because the diaphragm in the actuator is split and so the vanes are "stuck" in one position. There is an actuator kit available for £320 fitted

I have to say I've not really noticed a lack in performance on-boost, but then I've not had the car for that long and never driven anything as new & quick (unlucky for me).

I'm also a bit of a sceptic, and the lights have gone off since a few days after I got the car backand haven't come back on. This is except for the glow plug light flashing, intermittently and sometimes only for a few seconds.

I bought an ELM327 bluetooth adaptor and connected it to Torque on my phone. It showed the fault P2563 - Powertrain "Turbocharger boost control position sensor circuit range/performance". I cleared this and low and behold it came back, but this time only as a "pending fault". I don't know what the pending bit means - any ideas?

So does this really sound like a split actuator, or more like a faulty sensor, or some dodgy wiring on the basis that the glow plug light comes on intermittently? Is there anything else I can do to investigate?

Thanks in advance :-)

PS. Torque only measures a peak boost pressure of 1.5 bar - is that a normal level?

OBD II Pending Codes are also referred to as “continuous monitor” and “maturing codes”. An intermittent fault will cause the computer to store a pending code in memory. If the fault does not recur within 40 warm-up cycles, the code will be cleared from memory. If the fault recurs a specific number of times, the code will then mature into a diagnostic trouble code (DTC) and the MIL or “check engine” light will turn on.

That's useful info - thanks! So it appears to be an intermittent fault. Can a split actuator diaphragm cause an intermittent fault? I would have thought if it was split the fault would be more permanent - am I correct? If this is not the root cause, what are the alternatives, faulty sensor or wiring perhaps?

It might be the other way round - stuck vanes keeping the actuator in one position.

Try taking it for a good, hard, drive - it sometimes frees them up a bit.

If not, there was a post on here somewhere about using Mr Muscle oven cleaner to get rid of the carbon deposits in the turbo that cause the vanes to stick.

It could be the actuator that has gone as you say.

On the vRS is there a diaphragm? I thought they were electronically actuated, not by a vacuum line and diaphragm arrangement? - I could be wrong on this though as not an expert on the turbo on a CR170.

CR170's aren't renowned for turbo issues (unlike the PD140), so it may yet be something simple.

I don't know whether the actuator is pneumatic or electronic, but the technician said that a split diaphragm was the common cause of this fault. I haven't positively identified the actuator myself yet...

I did wonder whether it could be the other way around - is there a way I can test whether the vanes are stuck by measuring performance of the turbo somehow? A good clean always sounds like a good idea too, now I must have a closer poke around!

Cheers

Try the 'Italian tune up' first - get the engine nice and warm, and then do a few hard acceleration runs (safely) to get the turbo spinning and boosting. It can quite often free them up.

Then again, if it goes in to limp home mode whilst doing this and logs an overboost code you have sticking vanes one way or the other .....

Your technician is correct in that this fault does occur and it's usually a split diaphragm in the (electronically monitored, not controlled) actuator.

Cheers Ben - clears that one up then!

i had this recently, replaced the actuator, with the vw repair kit all good again

info and part numbers in my thread here:

http://www.briskoda.net/forums/topic/242051-turbocharger-boost-control-position-sensor/

Edited 29 August, 201213 yr by Dallan

Actuator is mighty fun to set up. Requires applying a vacuum to the unit and watching the value on diagnostic and when it's at the correct reading lock the actuator rod. Requires a very steady hand and a little bit of luck lol

I had mine go the glow plug light flashed then I filled up with diesel as I was empty the light went off got to work thought nothing of it finished work an it come back on took it to skoda and when he test drove the car it was off he told me not to worry about it, I went to go home got less than 200yards down the road the light come one and the engine light turned round to go back to skoda and by then the car had gone into limp mode I had the car for 2 months before it happend an to say I was ****ed off is an under statement! Took them a week to fix. If I was you I would get it

Looked at properly and replaced ASAP.