EDC17CP14 Problem after Polarity Reversal

I don't have an Autoscan, as it's a diagnostic tool.
ECU is an EDC17CP14 03L906022RN, operating according to the CAN protocol, not UDS.



I've created a testing setup where I can connect various control units to test them on my desk.

I messed up and accidentally swapped the positive and ground wires on the test cable for the EDC17. Now the control unit (on the table) only works sporadically.



If I try to communicate with the EDC17 using the standard "Engine Control Unit" function, I get the error message "ECU not responding".

I try the EOBD function, and it works most of the time. So, I can look at the errors and measurements.

After that, I tried it using the normal "Engine Control Unit" function, but the ECU is not responding.

Again about EOBD, it works.

Afterwards, I created a wiring diagram for the MWB's, and it works as well.

And then I can access the "Engine Control Unit" and perform all operations.



Is there an electronics expert here who might be able to tell me which components could have been damaged due to the reversed polarity? I've already removed the lid, and I couldn't find any signs of "overheating."

I still need to check if I can remove the entire circuit board from the case without causing any further damage.

Hello,

If it's working intermittently, I would check all the smoothing capacitors.
In my opinion, the active components of the control circuitry have survived, otherwise nothing would work.

Also, let's check if all the voltages are present and what their values are. 5V, 3.3V, or 1.xV, etc.

Best regards, Rainer

Thank you, Rainer, for your response.

Unfortunately, I am not very knowledgeable about that.

I still have an A4 engine control unit, it's also an EDC17CP 14 but already UDS.

I measured the capacitors and compared the voltages to those of the A4, and the voltages are identical.

I also measured the voltage on the pins, and I found differences on the following pins:

Audi (intact control unit)
T60/34 Motor for Intake Valve V157 - (12V)
T60/35 Position Sensor for Schaltsaugrohr - (12V)
T60/49 Motor for Intake Valve V157 + (12V)
T60/50 Position Sensors for Schaltsaugrohr, Position V183 (12V)

T94/26 Relay Starter (0.8V)
T94/27 Relay for small Heating Power (0,6V)
T94/70 Bypass Valve Air Filter (3.5V)

Tiguan (malfunctioning control unit)
T60/34 Throttle Control Unit J338 (4.4V)
T60/35 Engine Intake Valve V157 (4,4V)
T60/49 Throttle Control Unit J338 (4.4V)
T60/50 Motor Intake Valve V157 (4.4V)

T94/26 I can't find this pin in the schematic (0V)
T94/27 Relay for small Heating Power (0V)
T94/70 to Generator (0V)

Regarding the T60 pins on the Tiguan, it is not possible to determine from the wiring diagram whether the motor or the potentiometer is intended.

Hi,

ok, I meant the voltages on the control unit's circuit board, but if there's just some kind of residue coming out of the connectors, then the semiconductors must have burned out.
At least the MCU power supply seems to be functioning, otherwise nothing would be alive.

I would like to check which pins on the control unit receive the operating voltage and then trace the traces to the corresponding voltage regulators, and then test them.

Best regards, Rainer