VW Tiguan Mk2 DSG Gearbox in Emergency Mode : Mechatronics failure/repair : Fault code 10666 - Position Sensor for Clutch 1 P173500 : KWJ Performance £1300 repair

 

I love the Tiguans, we spent a long time looking for this car, and in doing so I searched a lot of forums and understood the issues.
Weve had our car now for 4 years and 50,000 miles

Context

There are 4 main issues you can typically see with VW Tiguan's

1. cars with panoramic roof , drains get clocked == wet floors. Ive removed our drains. You should too
2. EGR cooler/valves/NoX fail.  Use high detergent diesel fuel ONLY. Our failed and was replaced 2024 (https://johnoldfield.blogspot.com/2024/06/vw-tiguan-mk2-2017-20-tdi-150-68000.html  68k miles cost £1300)
3. DSG Mechatronic issues (the reason for this post!)
4. Haldex issues (not seen yet but definitely needs a pump/guaze clean)

The car has been incredible, weve ran it from 24,000 miles (https://johnoldfield.blogspot.com/2020/09/goodbye-a180-hello-vw-tiguan-150-dsg.html)
to now (75k)
with the 2 big costs at 68,000(EGR/Nox) and 75,000 (DSG) miles 
otherwise its just been regular servicing and tyres (and 1 cambelt/waterpump)

anyway back to the Mechatronics failure


Car at 75,000 miles its  a 150 TDI DSG 4 Motion Tiguan
This is a 7 speed wet clutch system (DQ500?)


looks like this (not our car btw)

• The car can be driven but only even gears 2,4,6 (i put the car into full manual mode and used the paddles to smooth out the ride)
• Resets back to working ok if left for >40mins to cool down
• Fault reappears after >30mins driving

Fault code read by VCDS

1 Fault Found:

10666 - Position Sensor for Clutch 1 

          P1735 00 [00101000] - Electrical Malfunction

          Intermittent - Confirmed - Tested Since Memory Clear

          Freeze Frame:

                    Fault Priority: 0

                    Fault Frequency: 1

                    Mileage: 118929 km

                    Date: 2024.11.23

                    Time: 14:32:07

                    Engine RPM: 1386.00 /min

                    Vehicle speed: 65 km/h

                    Coolant temperature: 91  C

                    Clutch: primary stat: Driving

                    selected gear: GANG_6

                    Driving position: d

                    Engine torque: 132 Nm

                    Control Module temperature: 89  C

                    Accelerator pedal position: 43.2 %

                    DTC memory status: 37

Possible issues (in order of cost to resolve low to high)

• Battery (this is a simple one , if you have lots of fault codes check this out first, you might be lucky!)
• Mechatronics unit (sits on side/front of gearbox) (Most likely our fault given the code we have)
• Clutch packs / DSG gearbox

Car had a new battery this year.
And I have only this specific fault code and the way it appears after getting warm the most likely reason is a sensor/pressure failure in the mechatronics unit :-(

Given the number of cars with these gearboxes and the number of failures, there are now plenty of options to choose from to resolve the issue that dont necessarily involve VW dealers and huge waits.
Its still a very reliable gearbox (incredible piece of technology) but it can and does fail in various ways


Options to resolve mechatronic issues

• If you are spanners handy then DIY on the drive (it doesnt appear hard to remove the unit) to remove and send off to ECU testing (approx £385+) , but will also need to add gearbox oil and filter (£250+)
• Repair (approx £1300-1500 replace sensors/solenoids inc removal/refitting and fluids)
• Replace (approx £3- 3.5k ) new mech unit , will require recoding as well)

Please keep in mind though the actual DSG oil and filter are themselves relatively expensive if you are considering DIY

Our trusted garage dont do mech repairs so suggested we look around for a specialist.

Im in the UK in Warrington (WA5 postcode) , i narrowed it down to 2 places based on the Google reviews and experience of tiguans

1. https://kwjperformance.com/  
2. https://www.selectorgearbox.com/

I opted for KWJ Performance , a conversation with Kieran quickly gave confidence, he says they do 2/3 a week of this repair, and we spoke about the reasons/the repair etc

The car was booked in for them to

• remove mechatronics unit
• replace both clutch 1 and 2 position sensors (note I only had a fault on sensor1, replacing the other is preventative maintenance given its all apart and sensors are relatively cheap) inc new seals
• refit
• basic settings / road test +oil + new filter
• update VW service online record

turnaround in 2 days
They offer a 2 year warranty on the repair.

thankfully the problems did not extend beyond the mech unit into the clutchpacks/gearbox so that kept the cost down.

clutch pressures are fine.
basic settings applied ok (but they did say it took a while to get the car to adapt to the new sensors)

Total cost £1300

Car is now back, and hopefully thats it fixed.
Great experience from KWJ end to end, and they work on some far fancier stuff than a Diesel tiguan

Of note the car had never had a DSG gearbox service (75k) which is bad, but Im told the oil was ok and this did not necessarily contribute to the sensor/o ring failures.

Additional info

Heres some narrative I added to a forum recently as well when someone asked about the fault code.

age and mileage of car?

do you have a VW extended warranty? (if so take it to them)

Assuming you dont ....

I assume youve lost either even or odd gears?

Does it revert back to working ok when left to cool down?

The actual fault codes need to be read (someone with VCDS or a trusted local garage)

You also need to rule out the obvious cheap stuff (like failing battery)

Most of the time it would appear to be clutch position sensor fault (clutch 1 or 2) which show after 30mins + of driving.

this would need the mechatronics unit removed , tested then it can either be repaired or replaced and refitted.

note the oil is expensive (so its approx £250 just for that bit)

Hopefully you have a trusted garage locally.

they will either remove and send off

remove and fix (if they have the diagnostic kit and experience)

its pretty common these days so look for a DSG repair specialist in your area (post up first 3 letters of postcode and people whove had it done in your area might comment)

ballpark id suggest

if its the simple fault codes its £500 just to repair the mech unit

then you add in labour for removal and refit + new oil and filter

so if its just a sensor is around £1300-1500 all in

changing solenoids as well adds a little but not much

if the problems are deeper and also involve the clutch packs (unlikely) you can start doubling the cost. (at that point you might want to think about WBAC lol)

this is all independent garages, having this done by VW is much more (so you only really go that route if you have warranty)

just my 2p from what Ive read

(ours goes in for mech repair on Mon , 75k miles, clutch position sensor 1 fault code. approx cost is 1300 , for changing both clutch position sensors)