I am tracing the operation of the ECU. I want to supply it with power but what is the ECU voltage input that I should supply?

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    Well, it's likely to be 12V as that is what is supplied by the car battery, but in general it's difficult to answer your question as there are thousands of different ECUs. Commented Jul 13, 2016 at 9:59
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    What car did the ECU come out of? What are you trying to test on it?
    – Ben
    Commented Jul 13, 2016 at 12:03
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    Plug it to a car battery. Commented Jul 13, 2016 at 16:24

4 Answers 4


If you're talking about a regular 12V battery vehicle, then the ECU is likely to work from 7V until 14V with no problem. That's the usual requirement for this kind of component.


It needs a minimum of 9.6v from battery power from a 12v system if the battery is close to being dead lets say 8v left on it...then the car wont even turn over

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    Welcome to the site. I'm not sure how this answers the question about the ECU? The question isn't about starting the car, but rather about how much voltage the ECU needs. If you backed this up with links to information backing your claims, it would go a long way. Commented May 29, 2017 at 12:45

I used a Buck and Boost controller. Set it at 12.39 volts D.C. and forget it. The ECU line also powers the Distributor, so as to protect both ECU and vehicle Distributor.


It entirely depends on what your trying to do with it.

To power it on usually 9-14.5 volts will be fine.

However most modern (12years or so or newer) are smart enough to block certain functions unless there is at least 12.6v or in some cases 13.5v.

So as said it depends on what you want to do, if you want to power it up to test it with a diagnostic tool or its basic function just power it with a good fully charged 12v battery or even better a AC-DC power supply.

Put if you are trying to reflash/reprogram the ECU, fully test it or communicate with it then I would power it with a AC-DC power supply or battery support unit with around 13.5v

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