Can I salvage anything from my T5 train wreck :(

[aSimpleLife]

Well, some good news.
The van is running again. I let it run for 5 minutes.
For some reason it is no longer cutting out after a few seconds.
Which is was what was happening 2+ years ago when I got it back from the auto elec and left it on the street.
I assume its related to the battery being disconnected for a long time. But I thought the auto elec had tried that. And that I did too.
I also assume it will return to cutting out again soon. So Im not game to drive it anywhere yet.

I eventually pumped out all the 60L of old diesel in many 15 minute bursts with a 5 minute break between. The low pressure tank pump seems to have survived the experience.
Then refilled with 20L of new diesel and kept the low pressure tank pump running until all air bubbles had passed through the hose.
Then removed the hose and clipped the return fuel line back on the filter.
It took about 8 cranks to eventually start. After the first 4 cranks it seemed to get a bit closer each time. The first time it started it kept running.
There was no need to prime the second tandem high pressure pump, which is sometimes required apparently.

The engine warning light is still on as expected
Have a VCDS cable on the way. Will do a reset and see which codes remain/are present now.
It is possible the EGR system is due for some work. That error is dated earlier than the others. Which is how I remember it.
The other fault codes are dated later and around the same time. I am assuming with these corroded terminal/wiring/ecu is the most likely cause.

Tomorrow I need to get it up on ramps and make a thorough assessment of the fire extinguisher related rusting inside and underneath. The sliding door is rusted up again and I have repaired that once already. I've already noted loads of other surface rust spots and on nuts/bolts that just shouldn't be rusting.

Once this is done I can make decision on whether to try and drive it again or not.
If I try to keep it, then probably a new engine bay loom is my first purchase.
If not then I'll part is out. Once I have some space to do this
As long as it keeps running I should get a better price for my lowish km full service history engine and tranmission.
Worst case I'll strip and store everything and try to eventually pick up another identical one cheap.
That sounds like a plan, for now.

[aSimpleLife]

Checked for rust from fire extinguisher residue

Raised the van and did a fairly thorough inspection for rust.
Was surprised by how good it looked. Considering the doomsayers...including myself :/
Removed some but not all the underside covers.

Based on that I'll assume it's good enough to keep driving...until it isn't
Once I've got a vcds cable I'll assess the error codes.
I am expecting at a minimimum I'll need to do something about the EGR.

4 years ago I emptied 2 full size Presto ABE powder fire extinguishers inside and under the van from the passenger side and possibly inside the engine bay (can't remember). I later hosed everything out with water.
The van has been sitting out on the street for the last 2 years without being started.

The engine bay and under the vehicle only show a few rust affected bolts here and there which I have begun treating.
There is no evidence yet of it rusting from the inside out as had been suggested. At the time all the interior cover panels were on which seems to have largely prevented the powder getting into unwanted crevices?
My interior seats including the custom rear ones have significant rust though.
The passenger side door could be rusting from the inside out. I haven't taken the trim off yet.
And the passenger sliding door lower runner is almost rusted up again...and this has been repaired once already.
From the UK forums this seems to be a common problem and repair the with their salty roads.

Can't tell yet about corrosion of electrical connectors. Assume I'll start that process when I get my VCDS cable and review the current error codes. I'll be hoping to repair those rather than buying and installing new looms...if that's possible.
As mentioned for some reason the stalling after a few seconds that the auto elec seemed to have started is no longer happening. I don't understand this and as yet am not game to drive it anywhere. But it starts and runs and ive gone a few metres up and down the street and onto the ramps.

I suppose at any stage I can still go to plan B and part it out.
Maybe try and get a very good price for the engine and transmission. Then sell off the rest over time.
Or pickup another good condition but cheap identical van. At least the prices should continue to fall over time.

[aSimpleLife]

VCDS Scan Results

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.

[aSimpleLife]

Diagnose & Rectify EGR Fault Codes?

Now that I'm apparently left with just an EGR problem, the question is can I cost effectively troubleshoot and repair it?
I've done some research and watched this very good video and it's comments that's been linked here before.
In the video he had 4 fault codes. Different codes to mine. And his EGR valve seemed to be in a worse state than mine, based on the codes, which makes sense, and gives me hope of a simpler solution.

For some history, back in 2011 I think my EGR valve was replaced under warranty. After a warning light and limp mode. Something the dealer said was a known fault. I don't have a record of that now.
In 2019, before my fire, I had a warning light again. A new Exhaust Temperature Sensor resolved it.
Over this time I have seen both coil and engine warning lights. But have not accurately recorded which happened when. It may not matter?
Now I have the engine warning light only and limp mode from time to time. It's been 2 years since it started but I have not been driving it.
Unless I have an electrical problem, at 175,000km it seems likely I have a build up in my EGR valve. Especially when the last few years I was doing more short trips.
Have had the van from new and it's never used any coolant and I am pretty sure it is still not using any oil (hasn't even had an oil leak .

My pathway from here starting from lowest cost seems to be;

1. Check all earths and wiring connectors. Not sure how to do this yet. A physical inspection. But to be sure I need to learn how to do a proper electrical test. Otherwise I could start doing more work unnecessarily.

2. Try the Liqui Moly Diesel Engine Intake Decarb spray as recommended here on another thread.
If I keep the van then this should be done as regular maintenance?

3. Start replacing sensors. Not sure how many there are? Could the Exhaust Temperature Sensor have failed again after only 3 years? I'll need to get current prices before deciding if this is worth the cost?

4. Remove and clean the EGR valve? The video stated this would be a waste of time. But the comments suggest otherwise. I suppose once it is off I can make that assessment. I can clean, reassemble, reinstall and hope for the best. Or if it looks too bad while off I could decide to just buy and install a new one?

5. Replace the EGR valve. Apparently non genuine are not good value? Change EGR to D version? (does this apply to a CAAC engine?) I'll need to get current prices before deciding if this is worth the cost?

6. Cheap blanking option. There is the controversial Tafmet EGR valve simulator with blanking plates for CFCA engines. This looks affordable and easy to install.
However they don't make them for my CAAC engine. All they have which I don't understand yet is the EGR valve blanking plates with gaskets for Audi VW Seat with 2.0 TDI CR Diesel engines.
Maybe there are other options I haven't found yet?

7. Full price blanking option. Apparently to do this properly means blanking the EGR and catalytic converter and deleting the DPF including a tune with ecu remap? 5 years back I was quoted around 3k for this. Not a cost effective option. Especially when it's not legal.

Note - Also recommended here is that a genuine Provent 200 catch can on the blowby reduces buildup considerably? (for the future if I was keeping it?)

[aSimpleLife]

Missed 1 symptom...is this turbo lag?

I took the car for a 3rd short drive today. Just another few km and not over 60kmh.
There was 5 seconds of very low power until I assume the turbo kicked in.
In at least 1st, 2nd and 3rd gears (I didn't really go far or fast enough to test 4th).
This seemed much worse initially when cold. I think it got better as it warmed up. But didn't want to drive too far until I understood what it might be.
Assume this is turbo lag?
Which is nothing to do with limp mode? (that is throttling at 3000rpm?)

Had sort of noticed this on the first 2 short drives. But put it down to the vehicle warming up. And not having been run for over 2 years.
Today it seemed much more pronounced though.
Don't remember this being such a problem before the 2 years of inactivity. There was always a little turbo lag with the 103kw CAAC motor. It had never seemed to change over 12 years of driving it.
Ran another VCDS test when I got home and still have just the same 1 fault code which is EGR related.
But could this be related to the EGR fault?
From a little research so far, it could be a fuel related problem? Which won't always produce an error code?
Is it possible Ive caused a new problem 'while pumping out the 60L of old diesel using the low pressure fuel pump in the tank? And if so what might it be?

[aSimpleLife]

Liqui Moly Diesel Engine Decarb - New Problem

Been side tracked for a while...then first job back I've caused the van stall every time I start it.
It's seemed I've created a fuel problem by using Liqui Moly?

Before trying to remove and clean the EGR valve, to attempt to remove that fault code, I thought I'd attempt using this Liqui Moly cleaner. I was trying to follow this advice in this thread;

https://www.vwwatercooled.com/forums/f28/diesel-engine-decarb-117271-post1220020.html#post1220020"

The best way is to unbolt your EGR pipe at the intake flap, with the engine off, and pump that area full. Try and get the hose up in towards the manifold / four inlet ports. Bolt the EGR pipe back up and let it sit for a good while, and then try and start the car, which will take a bit of cranking. It will struggle and run rough till it clears. The next step is to spray it in with the engine running, I do it on idle and just stop as it labours, but I put it in PRE TURBO where the PCV inlet just before the turbo is in the air intake...Put it in anywhere AFTER the MAF and you will get some effect...

However I wasn't yet sure which pipes to remove to do this.

I watched the Supercheap Liqui Moly Diesel Engine video and it was only showing it being used in the inlet manifold/throttle body area. So I thought I'd try that first before I could establish where I should be using it for EGR cleaning. Although my inlet area looked very clean compared to the video. I still used 1/3rd of a can doing this;

https://www.youtube.com/watch?v=3agltbN4C7M

Then took the van for it's longest run so far. About 20km mainly on the freeway. All went well.
I returned home and did some VCDS tests. As a new turbo code had appeared previously. Starting and stopping the van a number of times while doing this.
I did a codes reset before my final test.

Next day I've started the van and it ran for about 10 seconds, sputtered, then cut out.
Tried it another 5 times and it cuts out after 3 seconds each time as if it's starved for fuel.

Left it for a couple of days and have just tried it again.
Same thing happened. Ran for about 10 seconds the first time before sputtering to a stop. Then cuts out after 3 seconds every subsequent time.

Unless it has returned to my previous immobiliser problem...which was similar...but I assume it hasn't.
I have just caused a new problem using Liqui Moly...or by performing the codes reset after this?

I am not sure yet what to try next?

[aSimpleLife]

Stalling after 3 seconds - Liqui Moly or Immobiliser

Right now I still can't get past the van starting, running for 3 seconds and stalling.
This is since the morning after I used Liqui Moly Diesel Engine Decarb spray (although after that, I drove car for 20 mins at highway speeds for it's first big drive in 2 years...started and stopped it several times while vcds testing...and then reset all fault codes).

I now don't believe this 3 second stall is related to the Liqui Moly.
There are no new VCDS fault codes since I used it.
I feel it's a return of the possible immobiliser issue from 2 years ago...which had somehow resolved itself...probably from a reset after 2 years with the battery disconnected.
Back then, I was getting an intermittent engine warning light and limp mode, and my vw mechanic directed me to an auto elec when he had trouble getting vcds to complete and fault codes were appearing which should not have been there.
The 3 second stall problem somehow started with the auto elec...and after 2 weeks he gave up on it too.

I tried a short battery disconnect with no change.

I then disconnected the battery overnight and recharged it (it is an almost new battery).
The one thing different this morning, is the first time it ran for about 8 seconds before stalling. Then after that it was back to 3 seconds every time.
I have noticed this before over the last couple of weeks that I've had this problem.
But don't understand what it might be telling me?

I think what I need to do next is learn how to make vcds turn off the immobiliser.
If I can do this and it no longer cuts out, then I know it's the immobiliser.
If not then it could still be either the immobiliser or Liqui Moly.

Back to the Liqui Moly for a moment.
I believe I sprayed it in the right place.
The large hose I disconnected from the "throttle valve module" ("throttle body") must come from the air intake/turbo making it downstream of these and also of the "Air Flow Meter" (MAF sensor).
I followed the afore linked Liqui Moly video on the Supercheap Auto site and these product instructions.
"This should be positioned downstream of the air flow meter/turbocharger/charge air cooler, where possible directly in front of the intake manifold."

It is still possible the Liqui Moly has coated or damaged a sensor but I am not sure which one or what to do about it?
Perhaps a "Throttle Position" sensor and/or an "anti shudder control" sensor?
I would have expected others to be reporting this though...which I didn't find.
It's been suggested I use a "throttle body cleaner". But which one for a diesel?
I am especially cautious now about spraying anything more inside this engine that I don't understand well enough

And back to the immobiliser.
If it is this, then it is likely a false positive caused by a broken/corroded wire/connector. Apparently not uncommon with TDI's.
Earlier in the thread it was suggested I replace the engine bay wiring loom.
I've watched some videos of people diagnosing and repairing these problems with a a multimeter and soldering iron...I have both of these...but don't know how to use them properly yet.

Next step seems to be to learn how to use vcds to turn off the immobiliser.
EDIT - it seems like I got this option wrong - it's only possible on Immobilizer gen 1 or 2 - my T5.1 2010 must be gen 3 or 4 - and it seems this option is no longer available


A couple of other observations;

- when the engine cuts out...my "Moo" valve seems to have become louder and longer since I used the Liqui Moly. But I don't think its' related to the 3 second cut out problem?

- and also when the engine cuts out...there is a new high pitched sound I don't remember before.
Could it be this "...the TDI makes a high pitched whine for about 20 seconds and this is the shutdown flap remaining closed blocking air from entering the inlet...Its the electronic throttle body unit, it performs a post self test..."?
This is the area where I sprayed the Liqui Moly.
But again it would not seem to cause this 3 second cutout problem.

[aSimpleLife]

Why does my van start and then run after sitting for 3 months or more?

Just a quick update and question in case this narrows down the cause of my problem for anyone.
Haven't given up yet on my 2010 T5.1 that I've had since new...but haven't made the time or enthusiasm yet to tackle a job that's probably beyond my limitations.

My main problem continues to be when I start the van it runs for 3 seconds and then stalls, every time.
It seems to be an immobilser problem, which started after an auto elec tried some workaround while diagnosing my EGR fault code that probably wasn't the EGR and more likely electrical and related to fire extinguuisher residue.

Today afer 3 months with the battery disconnected (again), it started and ran.
(prior to this I had disconnected the battery for days and even a week without any improvement)
It is the second time this has happened now.
Previously before Christmas, after 2 years sitting with the battery disconnected, it started and ran for a couple of weeks.
Then the day after using Liqui Moly to try and remove the EGR fault and my first long drive, it went back to stalling after 3 seconds. Leaving me uncertain whether it has returned to the previous immobiliser problem, or was a new problem caused by me using Liqui Moly.
Now it seems likely it was just a return to the previous immobiliser problem, triggered by the first long drive
(I had taken it on a number of short drives over 2 weeks prior to that with no problems).

[Sunny43.5]

I wonder if there is a loose connection somewhere that cause of the problem , as you said it ran for period of time once and now does not want to run again . A mate of mine had near new Range Rover years ago which would cut out going around a roundabout , after a whole month at the dealers and most of the dashboard etc removed they eventually found an airbag wire running up the steering column was loose and it had rubbed through shorting out the van . Things like that can move just a few mm and be touching something or not connecting properly to other parts .

[aSimpleLife]

Yes. It seems like it must be electrical. Somewhere. I just need to make the time to teach myself how to diagnose electrical faults properly. I think I've got all the tools I need now. And there was some advice earlier in this thread. Just have to finish this driveway, get the van off the street and in the garage (while it's still running), and then just keep going till I resolve it, or give up and part it out

[Sunny43.5]

Would seem a sad thing to part it out just for what sounds like possible issue with wiring etc . I would grab a few of the harnesses around the steering column and other dash areas then in the engine bay give them a shake or pull and see if that gives result .If you have the diagnostic have you done adeep scan to see what it shows , my Launch V pro series tool scans all the cars systems and tells you where faults are , once it shows a fault you can then home in on connections etc for those shown faults .

[aSimpleLife]

Yes it would be sad...and we've been through a lot together. The only new car I ever bought...or am likely to. Which is sort of why I've kept paying the rego for the last couple of years while I've been busy working and renovating. And I've also got a lot of moving coming up, so the van would be very useful.

I've got a Ross-Tech VCDS that I don't know how to use well enough yet. And a full copy of the T5 workshop manuals. So in theory I just need to get it off the street and spend the time learning and working on it.
Not sure if the Launch V pro series tool is better/easier but it seems like a big investment. Now that I should have the time...I don't have the money

[Rebuild]

yes i'm leaning to it being an intermittent electrical fault somewhere as well, from your descriptions.
Hope you find the problem.

[aSimpleLife]

Thankyou. Also received a suggestion from a general mechanic to check an electrical connector at the back of the fuel injection unit. But I don't want to touch anything while it is still running and I can drive it into my garage and knuckle down and work on it. Problem is I STILL haven't finished my long steep driveway. Clock is ticking on the latest 3 months worth of rego

[LogicprObe]

Firstly, you need to get rid of that EGR fault.
Now that you have VCDS, you can test the EGR.
Instructions are available in the Rosstech forums.
If it fails the test, replace it.
Then you need to 'adapt' it into the system.
Also available on the Rosstech forums.
As for the EGR, I have a CAAC motor and the last EGR was the Chinese knockoff on ebay available out of Melbourne and it has lasted longer than the two genuine VW units I have installed (up to 540,000kms now)
Mine seems to blow them around 140k.