Good evening everyone.
My names Matt and I am new to the forum with this being my first post. sorry this is going to be a long read.
I recently bought a XF 3.0d S with 125k on the clock and with a "restricted performance" issue that I was hoping to fix. I got it cheap because of the restriction and couldn't pass up the offer.
I am a mechanic by trade so know my way around some makes and models mostly year 2000's and prior and not to up to scratch with modern cars.
So a little about the car, the chap who had it before me had the warning come so he took it to a dealer who diagnosed it as a turbo needing replacing. They carried out a smoke test and found it leaking from the turbo housing also found a P1247-00 low boost pressure DTC.
He then took it to a independent garage who diagnosed it with a clip missing from the intake pipe to compressor housing (miss diagnosed leak test from jaguar) they refitted it correctly and carried out a vacuum test. They found that a pressure control solenoid was faulty so replaced it. This did not fix the fault. They also found a split pipe from the vacuum test so replaced that which still did not fix the fault.
He then took it to a 2nd independent garage who found a DTC for low boost pressure, engine oil temp sensor circuit, ride height sensor F/R, Air flow sensor fault. They replaced one Air Flow Sensor and put a turbo on from the recommendation from jaguar, again this did not fix the fault.
He then took it to a 3rd intendant garage who found only the P1247-00 low boost pressure DTC, They checked the wiring and vacuum operation which came back ok. They then removed the exhaust and took it for a road test to which no faults were thrown. There recommendation is to clean the exhaust system.
He then took it to a 4th garage who specialised in cleaning DPF's. They took it off cleaned it, re-fitted it and this cleared the codes and the car drove perfectly.
He then had the car on his drive way after getting a work van and only used the jag every now and then. With no substantial long journey. after 2-3 months the restricted mode came back, to which he then sold it to myself.
I have had the car a little over a week now and found that the only fault code to be the P1247-00 low boost pressure, I also noticed the "service due" notification. Work I have carried out is so far, changed the recirculation valve with new OEM part. the old one looked ok no rust but heard this is a point of failure, whilst that was off I renewed all jubilee clips on all boost pipes, I replaced the o-rings on any part I could see oil leakage around its general area, on the throttle body housing and the elbow connecting to this. Changed the fuel filter and air filter with OEM parts. I have yet to carry out an oil change. I have visually inspected the intercooler to which I cant see any cracks or the orange gasket sticking out, I have also visually inspected the manifolds to which I cant see any cracks (no oil marks around the manifolds or intercooler) I still have the P1247-00 code and restricted performance mode. I have bought a leak tester to try next also to look for any boost leaks, but previous test came back ok. I also have an Autel 808pro that can carry out a forced DPF regen.
Now my question is can these cars put it into this mode if it knows it needs and oil change. Also which I find strange is that previously it didn't throw any faults or have any DPF warnings on the dash or stored on the ECU when they carried out the clean previously which fixed it before. Can the DPF block on these enough to cause restricted performance without throwing any DTC's?
Sorry for the long read, I am kind of pulling my hair out with this one.