Can I salvage anything from my T5 train wreck :(

[aSimpleLife]

The upshot is, I only seem to have ended up with an EGR fault?

While this should be good news, it doesn't seem to explain the things I've seen, been told and previous scan results
Perhaps I should not have told the VW mechanic and general auto elec about the fire extinguishers, as maybe that led them to make false assumptions. In the end both said they didn't want to work on the van any further.

As attached in my first post, in Dec 2021 my regular VW mechanic scanned my van and said the scan would not complete and I could have one or more earth issues as a result of corrosion. He did not feel the error codes were correct. At this stage the engine light (not coil?) was on and it was regularly in limp mode.
5 Faults Found:
1. 4807 EGR System - P0401 00 [104] Insufficient Flow
Intermittent - Confirmed - Tested Since Memory Clear
2. 11901 Manifold Pressure / Boost Sensor (G31) - P0236 00 [032] Implausible Signal
Intermittent - Not Confirmed - Tested Since Memory Clear
3. 4124 Sensor Reference Voltage B - P0651 00 [032] Open Circuit
Intermittent - Not Confirmed - Tested Since Memory Clear
4. 4881 EGR Valve (N18 ) - P1440 00 [032] Open Circuit
Intermittent - Not Confirmed - Tested Since Memory Clear
5. Engine Speed Sensor (G28 ) - P0322 00 [096] No Signal
Intermittent - Not Confirmed - Tested Since Memory Clear

Gave it to an auto elec with all this information and both keys. He by-passed something and thought it was successful. Whatever that meant. But when he reconnected the battery the next week the van would start but only run for a few seconds. He could not resolve this. Can only assume now that he had somehow triggered the immobiliser? And for some reason he did not know how to resolve this. Towed the van home and parked it out on the street. Thought I''d tried starting it a few times but it kept cutting out? Thought I had tried long period of leaving the battery disconnected in between? In the end disconnected the battery and thats where it sat for the next 2+ years

Have just recently got the van started again. The cutting out after a few seconds has gone? I can only assume the long period with the battery disconnected has reset whatever immobilised it? Haven't been game to drive it very far yet. Is it likely to start happening again?

Now have access to VCDS scanning and my first scan result was;
Address 01: Engine (J623-CAAC) Labels:. 03L-906-022-CAA.clb
2 Faults Found:
4881 - EGR Valve (N18 ) P1440 00 [032] - Open Circuit
Intermittent - Not Confirmed - Tested Since Memory Clear
4900 - EGR Sensor 1 P0405 00 [175] - Signal too Low
MIL ON - Confirmed - Tested Since Memory Clear
Address 03: ABS Brakes (-----) Labels: 7E0-907-37x-MK25AXT.clb
2 Faults Found:
01314 - Engine Control Module - 004 - No Signal/Communication – Intermittent
01314 - Engine Control Module - 013 - Check DTC Memory – Intermittent
Address 08: Auto HVAC (J301) Labels:| 7E5-907-047.clb
1 Fault Found:
13701376 - Function Restricted due to Missing Message(s)
U1111 00 [008] - - [New feature! Extended UDS fault detail is only supported by cur gen i/f]
Intermittent - Confirmed - Tested Since Memory Clear
Address 09: Cent. Elect. (J519) Labels:. 7H0-937-08x-09.clb
Subsystem 1 - Part No SW: 7E0 959 801 B HW: 7E0 959 801 B Labels: 7E0-959-80X-V1.CLB
Subsystem 2 - Part No SW: 7E0 959 802 B HW: 7E0 959 802 B Labels: 7E0-959-80X-V1.CLB
3 Faults Found:
03303 - Response Closing Status of Rear Left Door - 008 - Implausible Signal - Intermittent
00446 - Function Limitation due to Under-Voltage - 002 - Lower Limit Exceeded - Intermittent
03444 - Ignition Starter Switch - 008 - Implausible Signal – Intermittent
Address 17: Instruments (J285) Labels:| 5K0-920-xxx-17.clb-SRI1
1 Fault Found:
9453074 - Fuel Level Sensor 1 - B103E 1B [008] - Resistance Too High
Intermittent - Confirmed - Tested Since Memory Clear

I have since done a number of scans. Have reset the dtc's. And driven the van about 10km.
This is my latest full scan result - just 1 now fault;
Address 01: Engine (J623-CAAC)
1 Fault Found:
4900 - EGR Sensor 1 P0405 00 [175] - Signal too Low
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 175221 km
Date: 2024.11.17
Time: 03:29:50
Engine RPM: 860.00 /min
Normed load value: 31.0 %
Vehicle speed: 0 km/h
Coolant temperature: 76 °C
Intake air temperature: 31 °C
Ambient air pressure: 980 mbar
Voltage terminal 30: 14.220 V
Unlearning counter according OBD: 40
Air mass: actual value (mg/stroke): 341.0 mg/stroke
EGR Vacuum Regulator Solen.val.: activation: 100.00 %
EGR Solen.val.: actual value: 100.00 %
EGR valve: offset closed: 4.00 %
Actuator for high pressure EGR: status-Bits 0-7: 0
Actuator for high pressure EGR: status-Bits 0-7: 55
Actuator for high pressure EGR: status-Bits 0-7: 0
Actuator for high pressure EGR: status-Bits 0-7: 0
High press EGR actuator: actual unconditioned volt val: 6.6 mV
Readiness: 1 1 0 0 1

I presume this other EGR code, gone since the reset will eventually return?
4881 - EGR Valve (N18 ) P1440 00 [032] - Open Circuit
Intermittent - Not Confirmed - Tested Since Memory Clear.

The engine warnig light is on. But not the coil warning light.