An interesting defect on my Touran

Had an interesting defect and I've shared with some friends over a chatgroups, One of them told me is "blog-worthy" and asked me to update my blog. ok....

The situation started with my dad calling me saying that my Touran had a defect (what's new right...). I thought it was some usual issues like those that I have previously written about. I, Me, Myself, Ivan: Defects and Symptoms encountered - Volkswagen Jetta and Touran (ironman76.blogspot.com)

Turn out, the car, once engine off, the power supply was totally cut off, as shown in the picture below.

What is your first thought? Battery I suppose... but for me, I don't think its battery issue. 

I'm using a Tsapa Battery(120X). I overheard some issues experience with Tsapa battery (not 120H or 120X), so I thought maybe 120X also got problem. So first check the battery.

Result, a super healthy battery with 13.3V. So what's next. probably fuse.... checked all, all not blown. 

Then try to use multimeter to check wiring connectivity.  

Interestingly, the voltage difference between the grounding point is >10v!!! Had previous issues on grounding cable so I actually had installed another grounding cable with a "fake HKS" grounding wire. 
And turn out that grounding cable connector was open circuited.

I had previously damaged the original grounding connector and had used a self improvised self tapping screw to hold the ground cable. turn out, the screw thread seems to have loosen over the years and probably cause the open circuit. 

As a recovery action, first need to see if the self tapping screw can still fit it properly. But it was loose. so I decided to give a better ground connection by removing some of the paint. 

Then I went over to a hardware shop to buy a bolt and nut to tighten the grounding point. and ya, i still got spare "fake HKS" grounding cable. 

Once all is connection, I finally got power supply back in the car

but more errors appeared. 

And worst

Almost at wits end, but decide to trigger a fault on the speedometer and thankfully it worked with all the fault codes available back on vagcom. Means got change to reset and work.

However, after a reset, I encountered a steering angle defect and couldn't clear despite resetting it.

Eventually, I tried to go into the steering wheel adaptation page and managed to resolve the defect and was welcome with a clean error free message on vagcom.

Finally my defect is rectified!

For info... The key use of the battery is just to start the car. Once started, the alternator takes over the power supply function of the car. So what is the root cause of defect.

1. Suspect the self tapping screw was the root cause. having intermittent connection all these while. 

2. The additional ground cable had an open circuit. hence there is no additional grounding point even though there is intermittent connection. 

Recovery action. 

1. Sand away the paint and also use a bolt and nut to secure the connection better with an additional grounding wire as contingency.

Total cost for me. 

I went opposite my place to buy a packet of bolt and nut for S$3. 

Defects and Symptoms encountered - Volkswagen Jetta and Touran

Over the 10 years of ownership, there is a quote that I found on the internet.

"Volkswagen - Turning Owners into Mechanics for Over 50 Years" - www.pinterest.com

Edit: I realised most of car owners/car enthusiast will like to know more of their cars and more often than not, we had also subconciously became our own car mechanic. 

Anyway, moviing on to the key topic... Indeed both my Jetta and Touran did experienced plenty of issues. Together with some of the defects experienced by my friends who request my help, I’ve consolidated some of these common defects that I’ve seen.

To start off, this is my Touran on tow because of piston crack.

and my Jetta on tow because of the famous flashing gear / spammer (mechantronic unit MU failure).

Well, here are the consolidated defects.

1. Air Con not cold. 
My guess is one of the most common issue for any cars is air con. And the likely cause of it is usually compressor issue.

One of my colleague messaged me saying that her Golf’s air con was blowing out hot air intermittently. I was thinking this issue might not be a straightforward compressor issue. After doing a visual inspection on the Golf, I don’t think it was due to compressor. Hence, I drove around and observed the magical moment when the air con is blowing hot air.

Finally it did and I was re-checking the pipings etc. Thankfully I spotted the issue on the MFD...

No wonder it is blowing hot air lah...

After replacing the ambient air temp sensor located just behind the front license plate, everything was back to normal.

You can try this method also to do a self check on the air con system. Just press and hold. And after all the checks, it will go back to normal.

2. Gear at D1/D2 experiencing juddering. 
One of the most common issue experienced with the 7sp dry DSG (DG200) gearbox is juddering. I’ve experienced such symptoms on my Jetta when the mileage is about 16,000km. Send to agent to check and performed some “adaptation”. Well, it didn’t work.

Solution, Change clutch..

I can’t remember how many clutch my Jetta had replaced. Should be on my 7th or 8th one now. Does it have any long term issue if don’t change? I’m not sure, I usually changed immediately once i experience juddering. Don’t want to risk any further damaged.


3. Piston Crack.
Another common issue experienced on the VW twincharged engine is piston crack.Both my Jetta and Touran experienced piston issues.
Here’s the pic of my Jetta’s piston (Picture taken by workshop)

My Touran’s piston (only one cylinder is cracked)

How to verify which piston is affected, a compression test can be performed on the piston.

The results might not be for the faint hearted....

To rectify, there is a need to do a major overhaul and can choose to use forge pistons like Wossner which I am using.

At the same time, hopefully the workshop can help to clean up the internals.

4. Unstable idling.
I think this is one of the most common and probably most difficult to identify the source of the issue.
I had inspected my intake valve and it is really dirty like this.

Some workshop is able to perform cleaning in-situ. (Picture is after cleaning)

Other than changing during major overhaul, my intake valves are also cleaned and re-used.

Another possible cause of unstable idling could also be due to dirty throttle body.
This is a picture of from my Touran.

After cleaning and see the difference. See how clean it is, looks new also.

Another possible cause of unstable idling could also be a oily MAP sensor.
This is a pic taken from my Jetta and can notice a layer of oil coated at the probe of the sensor.

After cleaning with contact cleaner.


Another possible cause could also be the spark plugs.
These are my plugs which I was told it’s “normal”.

Finally, it could able be cause by dirty fuel injectors.
My Touran had experienced unstable idling and it was rectified after pouring a bottle of injector cleaner. The one I used was 3M. (picture taken from the web).

5. Turbo fin damage
Another common problem experienced is the turbo and it was related to the fin. For mine, the fins was loose. And I had to replace a new turbo. Of cos I took the opportunity to upgrade to a hybrid one.

My replacement hybrid turbo by Turbo Technics.

6. Oil leaks.
Another common issue is oil leaks observed at the oil sump.
Oil leaks from my Jetta.

Old leaks from my Touran.

Find the source of leak and replace the relevant gaskets

7. More oil leaks from the top portion (Oil observed on the Engine Cover).

Oil was observed to leaking out from my Touran’s cam sensor.

Also spotted oil stains at the spark plugs area.

8. Another common issue is the roof lining and sunroof blind.
Here’s the pic of my Touran roof lining.

and here is the pic of the sunroof blind.

The sunroof blind which required to be replaced

One suggestion, replace when both failed. To safe cost.


9. Side door leather.
My Jetta also experienced the roof lining issue. On top of that, my Jetta side door leather panel also. starts to drop out. Here’s how it looks like inside.

After replacement, here’s how it looks.
Front door

Rear door.

10. Multiple flashing lights (ABS, Traction Control, TPMS)
If you ever experienced such warnings, its likely one out of the 4 sensors causing it.

Using a vagcom, it should show which sensor is the case.



But I suggest to replaced all 4. For my Jetta, I made 3 trips (one month apart each other) due to different sensors each time. On the 3rd visit, I’ve changed the 4th one. Subsequently for the defect on my Touran, I replaced all 4, to save time.

11. Water temp
This is a bit tricky. The speedometer water temp gauge is not accurate! When my polar fis is reading >100 deg, the speedo water gauge still remains at 90 deg.




Suspected the thermosta is causing the issue. t

After close inspection, there seems to have some stains that is causing it.


A closed up view

12. Coolant leak.

My Jetta also have a minor leak at the thermostat area. Which the coolant level will drop only when the car is driven hard.

Otherwise, I also experienced leak on the tank itself.



Try not to drive the car anymore. And if you really need to drive, top up with distilled water. Try not to mix coolant.

13. Drive shaft dust cover.
I observed some grease on my coilover and brake kits.

The cause was the dust cover broke.




14. Intermittent interior lamps.
This is interesting. I was trying to diagnose this and had a hard time trying to figure out what was wrong. Tried to replaced with another module and it also exhibit similar symptoms. Sometimes the interior lamps will not lit.



Interestingly, this was linked to the body control module. Removed out and do some contact cleaner cleaning and it works for a short while. Eventually, I replaced with a newer control module and recoded it to work.

15. Engine Cover Grommet
Another common problem...



How the new one looks like

I also experienced a broken engine cover at the grommet area.

16. Another common issue are the headlights internal wirings.
The insulation broke.

My Jetta had this additional issue on the connector which was giving intermittent connection.

17. Center Console (Cup holder)



Just to remove this damaged cover.


Need to remove the gear knob, and the console in front.



Need to remove the side

Need to remove the arm rest too.

 And the rear air con vent too.

Finally done.

18. Foot Pedals.
Mine broke too.



The stub behind was dislodged

Anyway, its been using for a quite a while also. 

19. FM Antenna.

Some soldering does the trick.

Does your Volkswagen have similar issues? Some of my friends told me their VW experienced radiator fan issues which I didn't yet.

I think I'm about 70-80% complete. Share what I have consolidated first and will update if I managed to find more pictures.

While these cars gave me the most problem, I think they are also one of the best cars I've owned.
a. Small engine (my road tax only $620/yr (gonna increase soon due to COE renewal),
b. Powerful yet fuel efficient (maybe something wrong with my Touran which I could hardly achieve >500km/tank, while my Jetta could reach almost 900km/tank)
c. Big boot space (especially my Jetta can keep a full size wheelchair and yet still got space for other stuff. Touran can house 4 bicycles (2 kids bike and 2 folding bikes).
d. Comfortable

Until now, I still cannot find a suitable cars to replace them.

Here's the link to my 2 rides still
Jetta - https://ironman76.blogspot.com/2020/07/my-jetta-sports-10-years-of-ownership.html
Touran - https://ironman76.blogspot.com/2016/12/volkswagen-touran-sports.html

Well, thanks for dropping by this post.

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20. Latest update on 4 Aug 20, my Touran couldn't start and there was a flashing P on the physical gear lever indicator (Speedometer only displayed ESP fault and when cranked, it showed move selector lever to P or N).

Car was towed to workshop for troubleshooting. Likely its the MU failure.