Author Topic: Outputs staying on when ECU powered down  (Read 4204 times)

Offline jdm ej1 95

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Outputs staying on when ECU powered down
« on: October 24, 2015, 12:42:45 am »
IM running a 3.8 board which i got recently as part of a repair exchange.

wiring is the same from this board to the old one.

the issue with this new ecu is that the fuel pump output and my fan output are coming back on once the ECU is powered down.  I did some searching and found out that the culprit is most likely the protection diodes on these outputs.

Aside from removing the diodes or completely rewiring my electrical system to send switched 12v to the relay instead of batt+  is there anything else i can do. 

maybe add a resistor in line with the output trigger?  what size?

Thanks in advance.

Offline VEMS

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Re: Outputs staying on when ECU powered down
« Reply #1 on: October 24, 2015, 11:04:30 am »
Hello Jdm ej1 95,

NO, either remove the protection diodes (but there is a reason they are there).
Or make sure your relays are not powered when the ecu is not powered, thats it, changing 1 wire from vbat+ to switched vbat seems te easiest (and recommended) route.

Best regards, Dave