NefMoto

Friends I have been trying to recover what I thought was a bricked ECU. ECU is 07K906032J 0261208858 ME7.1.1 of a MK5 Jetta 2.5L I5 car. I tryied to put into boot mode many times but always receive "Boot Mode Inactive" message. After what seems to be a healthy board I notice that some ICs doesn't have it needed +5V Vcc supply. For me ECU has a bad internal power supply.
Then my questions are:
1) anyone have some kind of circuit schematic of that board or of a similar ME7.5 one?
2) anyone knows which IC or board's zone converts +12V to +5V Vcc as power supply for whole board?
I have been tracing Vcc pads and routes but without luck until know.
Some help and advice will be nice.
Thanks,
Eliot

does this chip seem to get hotter than normal? i have replaced them before on dead ecus.

That 30343 chip is a CJ911 and does supply the main 5v.

Thanks a lot for the advice friends. Let me check and I come back to you.

Friends I check ECU board and it is cold like an Iceberg. I also check 30343 and it is cold too. I check voltage levels compared with other working ECU and it is not energized at all. Some protection diode or similar from +12V or ignition pin should be damaged. I need to know which ones are related. Continue tracing components.

i would still replace that chip first as a test.

Friends I found this two diodes, SG56 & EMB C522 in short. I have in a bad ME7.5 board a BYG 22D & LMP O1 working units, those will be compatible with that diodes?

Friends sorry to bother you with another question, do you know which IC is this one marked? It coding is 3043539 S867615.

no clue on that man. sorry, never replaced that one before.
i would assume most diodes in the same circuit are created equal though.

Thanks a lot mate  :)  :)  :)

Friends here is a review. I found previous indicated diodes in short. Those was changed. BUK128 Mosfet was checked and it is OK. As a precaution and following k0mpresd recommendation I change Bosch 30343 IC. Now Bosch 30343 is receiving+12V Battery voltage but +5V is still zero or almost zero. Something is in short around there. Anyone knows which IC is the one indicated which code seems to be 3043539?

isolate +5v output from 30343 (desolder pin and lift)

I found two (2) ground connections of smal SOIC-8 component previous mentioned. Problem could be in that little IC. That is the reason of my  doubt.

I was a bit unclear. Isolate the pin and measure if voltage is 5v to see if internal protection in 30343 disables output if current is too high.

Ok understood. Let me check and I comment results from tests.

Ok friend I have done some more tests and here are my results.
1) Take out previously indicated SOIC8 3043539 IC and found that ground connections are in board. I compared it connection with another good ME7.5 board I have and it has same connections. Inclusive with IC out board, ECU doesn't startup either.
2) I take out Bosch power supply unit 30343 CJ911 and start to solder and test pin by pin and ECU doesn't startup again.
3) Then I test continuity test with ground of each pin and compared voltage signal of a working ME7.5 ECU I have with the ME7.1.1 I am trying to repair. Here are the results.
ME7.5

   ME7.5         ME7.1.1   
1   GND         GND   
2   GND         GND   
3      0,03         0
4      0         0
5      0         0
6   GND         GND   
7      5         0,02
8      5         0,02
9      5         0,02
10      5         0,02
11      5         0,02
12      22         11,5
13      5         0,04
14      0         0
15   GND         GND   
16      0         0,07
17      12,2         0
18   GND         GND   
19   GND         GND   
20      12,5         13,3
21      13,1         0
22      12,5         13,3
23      5         0,02
24      5         0,02
25      5         0
26      0         5
27      5         0,02
28      5         5
29      5         0,02
30      12,2         0
31      5         0,02
32      2,4         0,02
33      2,4         0,01
34      0         0,02
35      0         0,02
36   GND         GND   

I also left you datasheet of the Bosch CJ911 power supply unit. But what seems ood to me is that pin 12 KL15 Ignition is OFF, it should means that simply power supply unit is turned off????

Friends after almost two (2) checking deeply this ECU I almost got a conclusion that the Bosch 30343 CJ911 is not turned on. If this IC doesn't receive +12V signal from KL15 ignition in it pin 21 it doesn't active 5v and other outputs. But problem is that I have been tracing it route withou luck at all. All I see are some resistors and a capacitor. After that I lost it in the other side of board. Anyone knows which it route or which components are involved?

man, after all this time, id just junk it and buy a new one. those 2.5 ecus are usually cheap.

I agree with you but I am outside USA and where I live, story is totally diferent. These ECUs are hard to find. Anyway I really appreciate your help and patience with me. During my research I found some info about this ECUs, then here is a diagram about ICs in ME7.5 ECUs that could be useful if anyone need it.

Get someone to buy one here and get them to ship it over.

I really appreciate that.