Audi A3 8v new gearbox wrong mechatronics?

[Law6on]

Hi all, new to this so give me a chance...

Just brought a 2014 Audi A3 1.8TFSI. It’s got 57k miles on it and is cat n. It’s also running big power - bigger turbo intercooler turbo back exhaust etc etc (360bhp ((180bhp standard)) ) Found out that the gearbox has been replaced with a 7 speed 2016 gearbox code RRF (car should have PYV). According to TPS either box is fine for the car but apparently the mechatronics is not meant for the car (Need to get part number and code for this) The gear box fitted has a sensor zip tied to it which is the gearbox speed sensor. They have done this as the gearbox has no cutout for the sensor to be placed in... I have no warning lights on the dash but a lot of fault codes come up when it’s plugged in (will post codes below) and when driving normally the gearbox is fine however when you put your foot down it often won’t change gear, usually revs to around 4k and then it’s as if you are hitting a rev limiter it just won’t shift up until you completely let off. Then when you put your foot down again it will rev out shift up and then tend to do the same in the next gear however strangely sometimes it shifts with no issues at all. My garage is telling me to change the mechatronics unit to correct one however the part alone is £1400 and I didn’t even bother to ask for a labour quote. I have no idea what the best way of going about this is or how to fix the issue hence coming here for advice. I was wondering if maybe there is a way of mapping the sensor out as if they make the gearbox without the sensor hole they must run fine without one?

Any advice or pointers in the right direction is massively appreciated! Fault codes to follow most relevant ones being at the bottom G240 and G28 sensors

DETAILED ECU INFO


CAN network gateway

Part #: 5Q0907530Q

Component: GW MQB High

Coding: 030100042F085A005B0002481C0B00000001000000000000000000000000 (hex)

Fault codes:

197175 Manufacturer-specific code


Central electronics

Part #: 5Q0937084AH

Component: BCM MQBAB M+

Coding: 07051C42C25106FD038C5004B31407A80800000000000000000000000000 (hex)

Fault codes:

526359 Manufacturer-specific code


Steering wheel

Part #: 8V0953521CH

Component: Lenks. Modul

Coding: A418 (hex)

[No fault codes]


Parking/steering assist

Part #: 5Q0919283B

Component: PARKHILFE 4K

Coding: 0000050011 (hex)

[No fault codes]


Airbags

Part #: 5Q0959655N

Component: AirbagVW20

Coding: 98CCC0000C0000005C5400CA00C800000065 (hex)

[No fault codes]


Instrument cluster

Part #: 8V0920970M

Component: KOMBI

Coding: 27AD0918228026000100FA00100000 (hex)

Fault codes:

13636608 Manufacturer-specific code


ABS

Part #: 5Q0907379AA

Component: ESC

Coding: 12F18AA234242A6F0178060641CC2948512C5480608294F4024100080608 (hex)

[No fault codes]


Power steering

Part #: 5Q0909144P

Component: EPS_MQB_ZFLS

Coding: 8103 (hex)

[No fault codes]


Ignition authorization

Part #: 5Q0959435A

Component: VWKESSYMQB

Coding: 030C0C (hex)

[No fault codes]


Steering column lock

Part #: 5Q0905861A

Component: ELV-MQBA

Coding: 5D00000000000000 (hex)

[No fault codes]


Heater & air conditioning

Part #: 8V0820043C

Component: AC Automat

Coding: 03100004000000011000000000001100 (hex)

[No fault codes]


Front passenger's door

Part #: 5Q0959592B

Component: TSG BFS

Coding: 001086205E01040000001002 (hex)

[No fault codes]


Driver's door

Part #: 5Q0959593B

Component: TSG FS

Coding: 00108E205C01040000001002 (hex)

[No fault codes]


Headlight aiming

Part #: 7P6907357C

Component: AFS-ECU

Coding: 011E00002B230200 (hex)

[No fault codes]


Transmission

Part #: 0CW300046C

Component: GSG DQ200-MQB

Coding: 0014 (hex)

Fault codes:

10657 Manufacturer-specific code


Engine

Part #: 8V0906264B

Component: 1.8l R4 TFSI

Coding: 0A2500322424010B3000 (hex)

Fault codes:

15377 Manufacturer-specific code


Infotainment system

Part #: 8V0035020C

Component: MU-H-ND-EU

Coding: 01730301FF00000021111101000A00002F02010701000100DE (hex)

Fault codes:

01584 Vehicle too low, pump up started

01585 Contact switch lockcylinder front seat passenger side (F242), open

01586 Contact switch lockcylinder passenger side (F242). close

01587 Igniter 2 for Airbag; Drivers Side (N250)

01588 Igniter for Head-Airbag, Drivers Side (N251)

01589 Igniter for Head-Airbag, Passenger Side (N252)

01590 Igniter for interruption battery (N253)

01593 Heated Windshield (Z2)

01592 Air Quality Sensor (G238)

01595 Type pressure control button (E226)

01591 Warning lamp for Airbag out, Driversside (K144)

01605 Potentiometer 2 for gear recognition (G240)

00513 Engine Speed Sensor (G28)


Obtained with Carista

[paintman]

Law6on said:

Hi all, new to this so give me a chance...

My garage is telling me to change the mechatronics unit to correct one however the part alone is £1400 and I didn’t even bother to ask for a labour quote. I have no idea what the best way of going about this is or how to fix the issue hence coming here for advice. I was wondering if maybe there is a way of mapping the sensor out as if they make the gearbox without the sensor hole they must run fine without one?

I would suggest you need compatible electronics. i.e. the appropriate ecu & sensors for the box you have fitted OR the appropriate gearbox for the ecu & sensors on the car.

[Jazoli]

I know it doesn't help but it sounds like you have bought someone else's problem, my rule of thumb is if you are going to have a modified car make sure you do the modifying yourself, you'd probably be better asking on audi-sport.net as there will be someone who has done this conversion I'm sure.

The airbag fault codes would concern me, has it been crashed/written off?

[Law6on]

Yeah as mentioned is a cat n repaired. Airbags are due to sears being changed and not wired in and passenger airbag turned off with key in glovebox

[GreenV8S]

Law6on said:

I have no idea what the best way of going about this it

I hope the price reflected the state of the car.

I think your options are to fix it yourself if you have the skills and experience, or pay a huge amount of money for somebody with the skills and experience to fix it, or sell it as-is. It sounds as if it has had money spent on the engine and gearbox - you may find the parts are worth more than the whole.

[xjay1337]

You should take the car to a specialist for VW/Audi tuning.

If you are around Bedford I would recommend AKS Tuning

If you are in Scotland area, then Ecotune.

If Manchester, AwesomeGTI

If down south (Portsmouth etc) then JKM...

[Law6on]

I’m Birmingham but may have to stretch to taking it to Awesome GTI I’ve heard lots of good things about them...

[stevieturbo]

Hopefully you bought this lemon very cheap to cover the major issues.

Can you find out why someone fitted the wrong gearbox in the first place ? who did the work ?

Or just buy the correct gearbox ?

[Law6on]

Thing is I believe the correct gearbox is fitted it’s the mechatronics which I’ve been lead to believe is wrong. Guy I brought it off is a 🤫🤫🤫 he’s just lying through his teeth saying there’s nothing wrong with it at all. Just trying to work out the best way of going about fixing the issue as all it comes down to is this one sensor and the gearbox fitted not having the cutout for it. Wondering if I’d be able to get someone to machine the housing so that I could fit the sensor. whatever happens looks like it’s going to be a big job

[imagineifyeswill]

I assume this is a DSG gearbox, Ive been working on a Seat Leon this week that had DSG problems, VAG gearbox and whilst trying to find info on it was told by the local specialists that the mechatronics units are coded to the vehicle chassis number from the factory and can not be recoded to another car so secondhand there virtually worthless. They told me they had fitted a complete secondhand box with mechatronics for a customer and could not get it to work as it obviously was coded to another vehicle.

[stevieturbo]

imagineifyeswill said:

I assume this is a DSG gearbox, Ive been working on a Seat Leon this week that had DSG problems, VAG gearbox and whilst trying to find info on it was told by the local specialists that the mechatronics units are coded to the vehicle chassis number from the factory and can not be recoded to another car so secondhand there virtually worthless. They told me they had fitted a complete secondhand box with mechatronics for a customer and could not get it to work as it obviously was coded to another vehicle.

There are guys out there racing and swapping DSG's into other vehicles....so one way or another they can be made to work.

But with so many modules in cars talking to each other these days...it does need someone fully conversant with these systems to diagnose and find a way forward. Ideally some of the specialist tuners who actually can reprogram such things. ( ie not generic file swappers calling themselves tuners or mappers )

But when saying there are sensors hanging on the car that should go into the gearbox...except there is no hole. 1+1= something isnt right. Machining a hole in the gearbox will do fk all if there is no pickup ring inside for the sensor to read. And if there was a ring there....there would be a hole for the sensor.
So get the right box for the car, or find out why that sensor is dangling there.

Or give up, break it, sell it for parts, auction it, whatever. Before it ends up costing you a fortune.