OEM management wiring: 1.8T => Mk2 harness install FAQ

Yeah, maybe someone will confirm about clicks coming from box, that would be nice information to get.
Whats regarding continuity I checked it already before installing box when I did wiring loom and routed wire from ECU pin6 to reach cluster.
But I will recheck it again today, just to make sure.

btw is it possible ECU is not sending signal ? I had immo defeat for my ecu. Couldnt it be connected somehow ?

 

I drove more than 40000 kilometers using that ECU with immo defeated, had no issues. After that I decided just install tacho convertor to have RPM on clocks.
Personally I doubt that problem is in ECU, but just thinking loudly as I don't know anymore key points I should check.

 

Today I'm gonna check whole wiring for continuity one more time.
If I will find no issues, I guess the only way left is to send MSD unit back to dealer as warranty item.

rubjonny, thanks for your concern and time!

 

Did that. Everything is fine and I even checked MSD instructions how to connect voltage triggered rev counter from coil negative terminal in order to confirm.
Got 14V between tacho pin10 (green) and earth, but tachometer does not move.

1. btw, could anyone tell the principle tacho is triggered by ?
As I understand Bosch ECU 3.8.3 provides low voltage signal which is ~1V and convertor transforms it to higher voltage, which is usually provided by standard coil fitted in all mk2's.
What else does this convertor ? Is there any frequency converting or something ? Are any other methods I could confirm I got right signal from ECU pin6 ?

2. In my case 1.8T fitted in mk2 1.3L CE2. I checked wiring diagrams for mk2 and noticed that U1 and U2 instrument cluster harnesses have much more wires mentioned in diagrams what's regarding tacho module. Maybe wiring harnesses U1 and U2 are different depending on engine ? Since mk2 1.3L came without tacho I bought cluster from other petrol mk2.

3. What is more strange for me. When convertor is wired in loom, between MSDs white wire (and this connected to ECU pin6) and earth I got 1V. I disconnect convertor, check between pin6 and earth and there's 12V. Is it normal ? It seems that ecu tacho signal interferes somehow with convertor. Convertor should just take this signal from ECU with no impact to it. But i'm not good ant electrics and might be wrong.

 

Hello nearly finished my conversion but my coolant light just keeps flashing at me fault code is 18058 p1650 databus powertrain missing message from instrument cluster ecu, 18057 p1649 databus powertrain missing message from abs ecu and 16486 p0102 mass air flow circuit g70 low input this one I think is a dodgy maf so I will replace that hopefully that will fix that but it's the coolant one I can't workout how to fix I wired the mk3 plug to the Mk4 loom plug to plug changed the sensor As well so not to sure any help would be much appreciated thank you in advance

 

I have striped my loom back to see if I wired my coolant sensor in wrong as my coolant light keeps flashing g2 03 goes to t10 4
My connection on the sensor is
Purple to pin 1
Brown/white pin 2
Green/grey pin 3
Brown/blue pin 4
I have used the plug 357919754 and coolant sensor 357919501a and also tried 6u0919501b

The only difference to what is says to do is I earth the earth on t10a is to the chassis not the head I don't think that can be the issue someone please help me I think I'm going insane

 

Hello mate thanks for the help I just rewired the coolant sensor as said but I still have the same issue any ideas? I turn the ignition on the light goes out 15seconds later it starts flashing again with the same fault code
18010 p1602 power supply terminal 30 low voltage
18057 p1649 databus powertrain missing message from abs ecu
18058 p1650 databus powertrain missing message from instrument cluster ecu
Please help me

 

Thanks for the help when I unplug the coolant sensor the light still flashes and if I bridge the gap from pin 4 - 2 the gauge will not go up but I had it running for about 30 mins the gauge did start to move but it didn't go much past 70 so do you mean the both the databus missing fault codes can be ignored? I don't have a level sensor or wiring for one and also another weird one when I turn off my ignition my fan starts and doesn't shut off do you think this could be connected to the coolant wiring issue cheers for the help

 

No it goes up slowly when plugged in but doesn't when you bridge the terminals 2-4 it's the four pin sensor on the side of the head

 

hi guys I'm desperate for a little help...
I'm currently fitting a auq motor into a berlingo van but cant seem to find an ecu pin out for the AUQ.
iv found the pin outs for the different plugs on here very helpful so thanks for that already guys..
any help at all is greatly appreciated
Gary

 

Brilliant that's extremely helpful.
Thankyou very much