There have been quite a few problems with the Bosh MED 9.1 ECU for the Polo along the way, some of which have been resolved, some not yet.
At first, the guys at the workshop that did the swap tried various ECUs from Audi/Golfs etc with 2.0 EA113, but there was then a problem with the accelerator pedal. Later, allegedly one ECU was burnt out and another was needed.
Theoretically the best way is to take the ECU from a Polo WRC Street, after a few unsuccessful attempts by my ‘tuners’ from near Warsaw I bought an ECU that came from a Polo. The numbers matched, but unfortunately it wasn’t that simple…
I ordered the engine controller from Cartech Electronics Ltd and I honestly do not recommend shopping there…
It was hard to find on ebay or allegro any controller for the transverse 2.0 TSI, but by googling I found the Cartech Electronics website. They had an ECU on display supposedly from a Polo 6R R WRC Street.
Price £282.98 GBP so theoretically similar or cheaper to completed auctions on ebay.de.
The company mainly sells motor controllers, so I hoped they knew their stuff and knew what they were doing, especially as the price of a controller is not cheap.
I chose the ‘Immo-OFF (Unlocked/Decoded)’ option because the engine donor was a Scirocco and the engine seller had managed to sell the ECU earlier….
However, it turned out that Cartech Electronics have a rather strange way of ‘IMMO OF’ which involves uploading some totally random software without testing it, which caused more problems than good. In the controller, the soft was coded for the DSG gearbox instead of the manual and it was not possible to change it normally. On top of that, the immo was not removed at all…. The engine would shut down after a few seconds.
When I reported this to the seller, they wrote back that they were sorry, but it is normal for the software to be severely messed up when the immo is disabled…
The engine controller for the Polka with 2.0 has also outgrown the SynekTune workshop.
They couldn’t find the software for the Polo, but by trial and error they managed to run the engine with the manual gearbox on firmware from a Passat 2.0 BWA.
Address 01: Engine (CDL) Labels:. 06F-907-115-CDL.clb
Part No SW: 6R0 907 115 HW: 8P0 907 115 B
Component: 2.0l R4/4V TFSI 0020
Revision: 5BH16--- Serial number: VWZCZ000000000
Coding: 0404000318070160
Shop #: WSC 66565 257 00032
VCID: 6FBBD1847B9616F30E9-803A
VINID: 9E69EAAAA0D3A878010C50C00C2B742475
No fault code found.
Readiness: 0010 0100
-------------------------------------------------------------------------------
Address 03: ABS Brakes (J104) Labels:. 6R0-907-37x-ESP90.clb
Part No SW: 6R0 907 379 AS HW: 6R0 907 379 AS
Component: ESP9.0i front H02 0002
Serial number: --------------
Coding: 21DD2885212400C984141472845900400900
Shop #: WSC 31414 790 50316
ASAM Dataset: EV_Brake1ESP90iBOSCH 003020
ROD: N/A
VCID: 0F7BB10417D676F36E9-805A
No fault code found.
On the dynamometer it worked ok, but when driving on the road with the ESP pump connected there was a issue when accelerating suddenly (when driving on half-gas there are no errors in communication with the ABS pump):
ABS sensors function correctly:
ABS pump errors:
Engine errors:
On top of this, after changing the ECU it was not possible to change the coding in the ESP pump (Bosch ESP 9.0i 6R0907379AS), any change ends with a message: ‘Out of range’ – even when trying to switch on the TMPS (I wanted to set the coding as in the factory Polo R WRC Street in the hope that this would help).
The factory Polo R WRC Street had a pump with the newer SW:
Part No SW: 6R0 907 379 BG HW: 6R0 907 379 AS
My ESP pump:
Part No SW: 6R0 907 379 AS HW: 6R0 907 379 AS
I wrote to my mate from Netherlands (iichel retrofiting) about this, he wrote me back like this:
The pump should accept at least this coding to simply turn on the TPMS. What I think is happening in terms of coding… you’ve probably seen that the VIN is part of the ABS coding. Your VIN in the ECU is probably the VIN of the Passat 3C, and the VIN in the meter is probably still the VIN of the Polo 6R. The ABS checks the VIN before accepting the coding, the VIN is mismatched, by two VIN numbers and rejects all codes.
A friend suggested that there was a VIN mismatch, which was noticeable in VCDS:
The engine repair shop tried to change the VIN in the ECU using the Flex:
which contributed to updating the body number in one place:
After this change, I tried changing the last byte in the pump coding to 01, but still no change:
possibly the VIN is also sewn into the IMMO, the immobiliser ‘software’ in the flash is disabled, but the ECU will still contain the immo block with VIN, MAC, PIN and CS. If the Passat’s VIN is still there as the VIN in the immo block, it could also be that the immo block is encrypted and cannot be read.
in addition, VIN changes triggered another error (through manipulation in the eep):
The main problem that I can’t live with is an interruption in communication with the ABS pump under sudden heavy acceleration. Symptom: with the gas to the floor, the speedo pointer jumps to 0 and all possible lights from power steering, ASR, etc. come on.
Also, the car sometimes hiccups on start-up (probably due to the lack of vortex flaps in the factory manifold) – unfortunately the SynekTune people had no idea how to disable them in the software… (fortunately, everything in the software was later corrected by Digitun).
Works as a web developer by profession. Also known as CNK, owner of a Shadow Blue Volkswagen Polo 6R since 2011. In his free time, he enjoys hiking in the mountains, cycling, and constantly improving his car.
