I have a main relay kill switch on the ground wires going to the main relay.So when the switch kills the connection the ECU looses power right?But aren't ECUs supposed to have constant power so the memory in the ECU is stored?

So every time the connection on the main relay is killed,my ECU is reset when the connection is reconnected right?

Isn't this bad for the ECU or am I wrong about this?

 

thats a good question.. im not sure. but why put the killswitch on the ECU and not somewhere else.. im assuming the killswitch is to stop theft?

 

Yea the kill switch is a antitheft device...its not specifically for the ecu but the ecu runs to the main relay so that's why I'm guessing it looses power also.

 

i doubt it will hurt it really, im not positive but i doubt it will.

 

true but if ur vehicle is tuned will it not reset the tune?
which if that is true then it will hurt the vehicle
im going to be installing a killswitch of my own so this is a good thread

 

No, it harm anything! All your doing is shutting off signal to the main relay, that's it, it's just an incomplete circuit, that's all

 

I doubt that it effects anything. But to give you piece of mind, tons of people do this in various ways.

 

the tune can't be erased by the ECU...the chip just doesnt work that way

 

x2 only that it doesn't harm anything. Since you are breaking the ground for the circuit, no power travels from the ECU to the main relay. Just like when you disconnect the negative from the battery, there is no longer power to anything in the car. The ECU's have a dedicated power source from the fuse box under the hood, so unless you disturb this circuit, your ECU will be fine.

Having the ground interrupted on the main relay is a good security device.

 

yeah that makes sense when its put that way.. im not the original poster but thanks for the info i plan on doing this to my vehicle in the very near future so now i know and i didnt even have to ask

 

Sorry to reply so late and sorry to bump up a old thread but I just seen this and had to tell you thanks!
I didn't know the ecu has a dedicated power source...this gives me peace of mind.Thanks!