SDU/FDU Logic board not closing pre-charge relay with 12V IGN on

[redman]

Hello Everyone,

New to the forums and my first post. Looking for help with an SDU/FDU V7 logic board. That I have purchased fully assembled.

Doing everything that I can to stay safe and not let the smoke out of anything. I fully understand the need for pre-charging. However the pre-charge relay will not close once I apply the 12 IGN on signal. The pre-charge pin/cable from the logic board stays high. Therefore I get a "500 Pre-charge error-stop" due to the 5 sec limit.

I am using two EV200AAANA one as the main contactor and the pre-charge reply.

Should I be using a N/C relay for the pre charge? Then once the required voltage is meet the logic board will open the relay?

[johu]

Can you measure the gate voltage of IC11? (voltage between left pin and right pin)

Should I be using a N/C relay for the pre charge? Then once the required voltage is meet the logic board will open the relay?

No. When the car is off then precharge is always on...
In fact I don't use the precharge output of the inverter at all, I just leave the precharge relay closed whenever ignition is on.

[redman]

Can you measure the gate voltage of IC11? (voltage between left pin and right pin)


No. When the car is off then precharge is always on...
In fact I don't use the precharge output of the inverter at all, I just leave the precharge relay closed whenever ignition is on.

Hello John,
First off. Thank you for your quick response.

I have already put everything back into the motor inverter housing. Can I run the PCB on a bench power supply to get you that gate voltage reading?

Before I pull the PCB back out. If I simply trigger the precharge relay and leave it closed like you say. I should get the motor to respond if everything else it fine correct?

[johu]

I should get the motor to respond if everything else it fine correct?

I don't know enough to answer this for sure but if only the mosfet is broken then yes, you can still run the motor

[redman]

I don't know enough to answer this for sure but if only the mosfet is broken then yes, you can still run the motor

Hello Johu,

After your suggestion to lock the pre_charge relay at power up. I proceeded to attempt to complete the motor drive sequence. I noticed the pre-charge error went away. However now the main contactor was not triggering even though the system says ready to run.

I disassembled the inverter and checked between the two pins as suggested. I got zero volts. I then tested to see if the IC was shorted. It check good. I then checked IC 9 next to is same thing. So I decided to check continuity from the heat sink out to end of the pig tail. Nothing. I pulled the pre made harness and found no continuity on ground, pre_charge, main and forward wires. From the connector out to the pig tail end.

At this point I need to get my harness issues resolved before I go further.

I have reach out to the seller of the harness regarding the matter. Keep everyone posted.

[redman]

The seller of the harness. Promptly shipped out a replacement for me. Installed it and everything works as intended. I am very happy with the service that I have received from this seller. They have been very helpful.

Now just need to figure out how to get regen working. I am using a Hall Effect Potentiometer for my accelerator.

[johu]

Nice to hear.
Maybe this long and boring video is helpful for figuring out regen and other things