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VEMS dead

Started by Bambi, June 10, 2012, 08:56:27 PM

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Bambi

My car suddenly died while driving. No fuel pump ect. No coms with laptop. Is there a known cause  i.e.  internal fuse, power transistors,  voltage regulator ... Running the AAN motronic 55 ecu. Alternatively, who is the closest repairer to Pretoria, South Africa?

gunni

Do you not have any connection to the ecu through your laptop?

My suggestion would be to send it to VEMS in Hungary.

mattias

Remove it from the car, try powering it on pin 27+30  (pinout here : http://www.vems.hu/download/v3/Motronic55/Audi/).
In case it consumes no current then something might have burnt clean through, there is a wire that acts like a fuse for this case.

If it consumes more than 200 mA then something might have short-circuited and draws all the power the +5V regulators can supply.

Maybe a good idea also to open the side of the case opposite the connectors and look for the smell of burnt electronics.

Still got to wonder what the cause of this might be, it's quite rare.

In the end, send to Budapest/Hungary.


Bambi

I powered it and it draws about 200mA on the powe supply's ammeter. I'll connect a multimeter tomorrow and do an accurate measurement.

I also have no comms to the laptop..

mattias

The  ECU seems to draw the normal amount of current.

Does it activate the fuel pump relay when you turn the ignition on, but not while cranking?

I would install the latest nightly VemsTune and see if it can make contact with the ECU, it might be in bootloader mode with a corrupt config or something along those lines. Odd either way.

mentat-vvo

#5
Good day, everybody.
I've recently purchased VEMS 3.7.
My problem is that VemsTune (VT ver 2011-07-20) does not see the device. All grounds are joined, power is 12.2 V.
I tried direct connection to RS232 port (through max232 on board) and USB<->RS232_TTL converter directly to the header near the MCU.
Both cables I used worked fine with MSAVR 2.2.
Then I've discovered that TX pin of the AVR is at 3.1v, but MSAVR 2.2 has 5v on it.
Resetting manually by shortening Res with Gnd lines in the header did not change state of the TX line.
PonyProg detects MCU device properly, but it shows all BL fuses are programmed, along with Lock1, Lock2, M103C, WDTON,
BODLEVEL, BODEN, SUT0, SKOPT, EESAVE, BOOTSZ0, BOOTRST. Datasheet says SUT1 should be programmed when BOD is enabled.
But, I dont know exactly if these settings mean anything if Lock1 & Lock2 are set, since they disable ISP-mode prog.
Max232 is alive (loopback ok). Atmega seem to stay in reset. Oscill shows no movement on TX line and others after reset.
The voltage on res pin is 4.4v. AREF pin is 0v. AVCC is 5v, power is good. Oscillator is running.
What should I do next?
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The problem was in ATMega MCU. It was replaced.