207cc THP Throttle body fault codes

[hoverbod]

2009 207cc 1.6thp
Any hints on this one greatly appreciated, as this is currently kicking my arse!!
Little bit of history:
Car had a death rattle on startup, if left to warm up rattle went away. I suspected the hydraulic tensioner on it's way out. But seemed fine once warm, so she drove it locally while I got round to doing it. Next it wouldn't idle, so told her to bring it straight round.
Diagbox gave "Not coherent" on the camshaft/crankshaft position, so suspected a jumped tooth due to the tensioner. Strangely No codes though. Car still drove well anything above idle. Free revving etc.
No time to fit it myself took it to me local garage with a full timing chain kit including new camshaft gears and VVT gear.
Garage changed all the cam stuff, found damaged guides, and knackered tensioner. etc, removed sump and cleaned out all the broken plastic.
When restarted car wont idle or rev above 2500rpm. Full suite of throttle body error codes (more in a bit). Swapped throttle body with borrowed unit from non turbo. Same codes, no difference. Swapped throttle body back. Found some info online that VVT errors can show up as throttle body codes. Checked the VVT solenoid, found it was clogged, and broken mesh section. Timing rechecked again, Replaced with borrowed solenoid from another car. Engine starts, runs and revs. All fixed!!!
Drove 100yards up the road, car goes in super limp mode. Drive half mile home.
We have codes P2121 P0121 P0122 P2122 and P3010 (all throttle body codes). Now the interesting bits. Throttle body opens and closes fully when peddle is pressed (peddle must be working AND body is receiving signal. Body passes diagbox actuation test.
Diagbox Parameters:

Measured Throttle angle 0 deg, doesn't seem to change despite peddle being pressed and Butterfly responding
TPS voltage 1 510mv (goes up and down when peddle is pressed, 500 is correct at idle)
TPS voltage 2 256,210mv (How is this possible?????)
Position of the camshaft dephaser 36 deg (this is about right)
inlet camshaft dephaser position reference value 5121 deg (miles out)
inlet camshaft dephaser electrovalve OCR 143% (should be about 6)

In addition, if I look at the accelerator peddle, it states 99.9% pressed all the time, but when pressed body responds correctly. The parameters given are in the right range.
Sometimes get huge value on TPS 1 as well
I have plugged the borrowed Throttle body back in, and get similar values. plugged and unplugged the VVT solenoid, that makes no difference. Also plugged in the old VVT solenoid without it being fitted.
Deleted all adaptive values. Car starts and idles fine. Boot it past 2500 a couple of times and it gets all upset again.
Now the questions:
1. Any ideas why the throttle body would be affected by changing the timing chain?
2. How can the TPS measure 256V on a 12v system?
3. Why does the accelerator think it is always at 99.9%?
4. Everything screams dodgy throttle body, but the borrowed one (from 1.6 non turbo) plugs in and runs (albeit pipes wont go on) and gives the same insane TPS values.
5. Why does the VVT dephaser have strange reference values, and what position is it measuring, there is no sensor as far as i can make out.
I'm going to try another accelerator peddle tomorrow, and have another correct used Throttle body on it's way (supplier sent the wrong one), but if anyone can explain these symptoms it would be appreciated, I'm pulling my hair out!!
Apologies for all the words.
Jamie

[gwest]

Jamie you have a very interesting problem! It might not hurt to disconnect the battery and pull all the connectors out of the engine ECU and check for anything out of the ordinary. I did have the throttle body on my 2013 DS5 THP165 pack up recently so they don't seem to be particularly robust.

[ILGARAGE TUNING]

I HAVE THIS PROBLEM IN MY VEHICLE. WHAT DID YOU DO TO FIX IT?
THANKS

[gwest]

You need live data recorded to try to identify the problem. In the above example there must have been a software problem to generate some of the aberrant values. Any indications that the VVT system is problematic should be addressed by checking the VVT solenoids, as in the above example. However, the usual cleaning technique of spraying with cleaner and blasting with compressed air is not enough- I can vouch for that. The solenoid should be stood in a jar of kerosene (or equivalent) so that the hydraulic part is covered, and then put in an ultrasonic cleaning bath until the solvent remains clear when changed. It can take over 30 mins.