[pat123fish]

Hi,my first post.
Passat 170 tdi sport 2006.Bought 2008 with 40,000 and 8mths warranty.
2009 had a prob with the limp mode.Restarted the car and all was well.Took to dealers for a read out.Nothing listed.Driving on motorway again at steady 80 Cruise control on and it went again.Pulled over and turned off (reset) then on way again.After several times during a couple months driving i went to dealers and told then all was not well.Car now out of warranty.They put in a new throttle sensor switch,it happened again week later,they then reimbersed me and said it was wiring from the glow plug harness and they changed it and a sensor(not sure which sensor they replaced).After it happened again they refunded me.I managed to get to them with the flashing light and the Garage workshop message still showing.As if i turned it off it did not save any faults on the readouts.So went away with car still with this intermittent fault that does not show up on main dealers vagcom(or what they use).
The car then was fine for 4 months and then on the motorway 70-mph last week it did it again.
Has anyone any ideas what i should look for or suggest anything please.Apart from this it is 100% and i love it.Just at the back of my mind i always wonder when it will happen again.I know basics with cars and wanted to try and solve it without the price of the dealers.Even though they could not find the fault.Thank you

 

[chittychittybangbang]

At least they refunded you after their remedy did not work, most dealer will tell you too bad.

Overboost and underboost should always throw a code. You didn't turn off the garage workshop message right? It should indicate a code. Very strange that you have no codes, is there a problem with CAN communication?

http://www.myturbodiesel.com/1000q/multi/limp-mode-TDI-fix.htm Take a look at this checklist and see if anything sticks out.

 

[pat123fish]

Thank you for the reply.
When i returned the car after the throttle sensor had been fitted they said that the usual problems that cause this are the sensor.I asked if it had thrown a fault up and they said no.They said if it didnt solve the problem then they would refund.When it happened again i took it back to them and they told me to pick it up in 2 days.A senior mechanic/engineer would keep it as his own and drive it to get the fault to come on.After this time he could not get it to do it and he changed the wiring loom and a sensor(not sure on which) again he said'in his experience' that is the problem.
A few weeks later when it went i kept the car running to show it had triggered the fault and they put the vagcom on and no fault was recorded.When i turn the ignition off it resets itself?
They told me there was nothing they could find and as such i decided to call it a day with them and go elsewhere.
The fault went away for months then has returned only once.I have tried the WD40 on the turbo and actuator,checked all the hosing and the fuses and cannot find anything.It has a new throttle sensor plus a wiring loom and one other sensor still from the dealers that they didnt remove after fitting.
I have hammered the car in high revs and put it under pressure,drove it really steady and everything else to get the lights to come on,but not a chance.You mentioned the CAN communication?
I have a BURY hands free system on the car,would this cause a concern? or am i going down the wrong track.
I have already looked at the list you supplied and nothing seems untoward.
As i say i can go for months without it happening and my driving style not change then all of a sudden it goes.
Thank you for your reply.Any ideas what to do next?
Pat

 

[chittychittybangbang]

CAN com was just a guess based on no codes but it shouldn't be the case. The hands free system will not do anything.

Such an intermittent problem is hard to troubleshoot. I can tell you that the throttle pedal has some backups so if it's malfunctioning it should throw a code. Most of what you are expereincing should throw a code, very strange.

See if a certain place or style of driving triggers it.