Advice needed on a unique problem - SOLVED -

[Ivorytoast]

Need some help from what I can only describe as a unique problem.

I'll start with a little backstory.
I've got a 2013 Caddy 1.6 tdi and a few years ago I had a dpf issue. I had the dpf removed and the egr mapped out.

Fast forward to now, I had the actuator replaced (4 months ago) at my local garage, they said I had a vac leak from the rocker cover so they plastic welded it. Problem is still there though, EML is on and this is now the unique part......if I drive off the van is fine in 1st and 2nd, get into 3rd and get to roughly 3000rpm and it goes into limp mode but no glow plug light flashing but if I drive in 2nd to say 2500-3000rpm, put it in neutral and coast the glow plug light flashes and I can drive in all gears fine, no loss of power, nothing? I've checked for Vac leaks and can't find anything, turbo spools, actuator works, n75 is fine. Would this most likely be the rocker cover issue that the garage said? I thought Sticky turbo vanes but it spools fine and boost is there? Any help would be appreciated, code is P02563 I believe.

Apologies if I've posted in wrong section. Just waiting to be authorised.

[Doc]

http://wiki.ross-tech.com/wiki/index.ph ... 563/009571

Have a look at the Ross-Tech page on that fault code, they have several suggestions on possible cause/solutions.
I can't say I've ever heard anyone talk of sticky veins on a 1.6TDI but that's not to say it can't happen.
It maybe worth logging with VCDS to see the measured values when the fault occurs.

[Ivorytoast]

Thanks for the reply, Doc.
nah, I think sticky vanes is unlikely. I looked through a fuse diagram to try and see if a fuse had gone for the actuator, could find anything that corresponded?

[Doc]

Have you done the logging to check the fault condition?

[Ivorytoast]

Is that with vcds? I don't have that.

[Doc]

There are a few systems which can data log on VW cars, VCDS is the most appropriate in my opinion.
Might be worth looking for someone with VCDS in your area.

[Ivorytoast]

What data should I specifically be looking for?

[Doc]

Measuring blocks for specified and actual position of the turbo actuator would be a good place to start.

[Ivorytoast]

Thought I'd add what I've found using what I have available (carista obd and torque app)

I am getting reading of
0.6 in/HG vacuum on idle
3.8psi of boost at 3000rpm in 3rd gear

Boost pressure control monitor Bank 1 test failed - value 65.28kPa

I'll do some digging into this but any light shed on this is greatly appreciated,

[Ivorytoast]

Went out this morning and played with vac lines, I've blocked off the rocker cover vac line and the 2 that go to the egr n75 type module. Took it for a quick blast up the road (literally 2 mins) and no limp mode or warning lights. I'll take it for a drive in a Mo and report back. It felt so sluggish before but now the throttle response feels great and the turbo has no hesitation.

[Ivorytoast]

Just back from a proper drive. No warning lights, no fault codes, no limp mode.

Everything works, just better than before. Boosts in every gear, brakes are fine. Egr must be leaking? It was mapped out anyway is it failed years ago. Didn't blank it off (should I have even with it being mapped out).