T6.1 CXEC 199ps Bi-Turbo - Multiple Faults in Limp Mode - Turbo Valve Position Error

[L33SNK]

Hi all,

I have a 2020 T6.1 bi-tdi with 75k miles.

During a recent trip, my van went into limp mode with flashing glow plug, and multiple fault warnings appearing, such as "ACC disabled", "parking manoeuvre unavailable", "ABS fault" etc.

I scanned the car with VCDS and have several faults complaining of invalid canbus data, no reference voltage, implausible signals, Sensor Reference Voltage B open circuit.

I believe this may all stem from the G580 turbo selection actuator assembly, as I previously had a couple of spurious faults a few thousand miles back with "turbo inlet valve stuck". This would clear when switching engine off and back on, however I am now stuck permanently in limp mode.

The fault now appears to be an Electrical Malfunction of the G580 position sensor with persistent fault:

"30551 - Position Sensor for Turbo Inlet Valve
P22D4 00 [10100111] - Electrical Malfunction"

Having searched through the forum, I have read others having full turbo assemblies changed out, when it in fact appeared to be this component. I suspect this component may have been on its way out and has now failed completely - or at least the electrical sensor part of this assembly has.

I would be happy to carry out a replacement of this component to rule it out, but wanted to seek collective advice if I may be heading on the right track, or if there may be something else at play.

For added info, I did have one fault scan showing cylinder 3 pressure implausible signal, however this has cleared again and may be a red herring, and caused by the reference voltage faults from the G580 sensor?

Some other work carried out previously was EGR valve, EGR cooler and EGR pipe replacements due to losing coolant.

Any guidance / advice will be much appreciated.

Thanks.

 

[manfrotto]

Maybe post a full vcds scan so "the collective" can get a better picture of what the root cause might be?

And welcome to the forum - lots of helpful advise on all sorts of VW T6 stuff.

 

[L33SNK]

Maybe post a full vcds scan so "the collective" can get a better picture of what the root cause might be?

And welcome to the forum - lots of helpful advise on all sorts of VW T6 stuff.

Thanks for the welcome.

I went to scan the van today and as my luck would have it, VCDS having issues connecting.

I also have OBD Eleven which connected no problem and managed to capture the attached logs, if they are any use.

I recently had the battery changed out for brand new one a few months back. The van would start instantly on crank.

Its now quite sluggish and takes a few turn overs before it fires up. Its also sitting idling just above 1K and there is a noticeable smell of fumes outside the van. It is not a happy engine at the moment.

I had the battery on charger overnight and it was fully charged up, yet the engine turn over was still slow.

I typically carry out all work on cars and reluctant to had this over to garage for fear of misdiagnosing and thus escalating the cost.

 

[manfrotto]

Thanks for the scans. I assume you have cleared the fault codes and the faults are since clearing the codes?

 

[L33SNK]

Yeah, I had the engine running and cleared all faults, with those ones remaining constantly active after clearing.

I seemed to have cylinder 3 pressure sensor, along with some engine speed sensors faults flagging but then they will clear again.

I will download the electrical diagrams to determine what sensors share the same circuit. Wondering if one component has went faulty causing the others to go blind.

I am suspicious of the turbo actuators since I had couple of the “turbo inlet valve stuck” faults appear then disappear again for long spells. I am not sure however which one could be the fault as I note both G581 and G580.

 

[manfrotto]

Can you determine where the fumes are coming from ? - One of the faults indicates a leak in the air intake system. It is not uncommon for EGR pipes to crack and leak. Might be a good place to start.