Power in through CEL or out from ECU?

[4ca]

Hi guys,

I am after information on the 'check engine light'.

The wire that comes out of the ECU that goes to the CEL is that a power wire out or does this wire receive power.

I am running an EJ22 on an engine stand and thought that I would get the CEL working. Ran the wire from the ECU to a two pin pilot light. One pin connected to this wire out from ECU, the other to ground. I expecting the light to come on with ignition power but......... Nothing!

This made me think that maybe the computer sends the signal to the light by earthing out the 'subject wire' and allowing power to be drawn through the light.

Not game to test the theory, and I don't have the correct wiring diagrams for a post 94, pre 98 EJ22.

Any help would be appreciated.

Paul

[tim_81coupe]

This made me think that maybe the computer sends the signal to the light by earthing out the 'subject wire' and allowing power to be drawn through the light.

You're on the money there mate. The ECU earths that connection to operate the CEL. 12V in the other side, and use a very low wattage bulb or as I prefer an LED.

[4ca]

Thanks heaps Tim

I was a bit nervous about putting power into this wire and letting the smoke escape from the ECU.......

Your a good man

Cheers

Paul