Need to read codes, but previous mechanic said i need to Ground Out the D4 wire? He undid it to turn Check Engine light off.? I checked it and its plugged into ECU, but can"t figure how to Ground Out the Wire. Anyone Know how to Ground Out the D4? Thanks..

 

Everything grounds to the chassis then to the battery. Which means you can ground to pretty much any exposed metal in the car. If you can't find the original hole it bolted/screwed into then secure it to metal with a self-tapping metal screw through the ring connector. If you can't find any exposed metal, take a flat-head screwdriver and scrape off a small spot in the paint where you're mounting the ground.

 

Year make model?

https://honda-tech.com/honda-civic-d...lists-1901557/

 

Ok I found the Screw just behind the ECU on an exposed Metal Plate. So now i just need to splice the D4 wire and we're good right. Oh i have a D16z6 engine on a EG Si..

 

Uh, exactly what are you trying to do? It sounds like you're traveling from NY to NC via CA.

 

You can't pull D4 codes on an EG. If you want to pull CEL codes, jump the service connector.

 

Thx, i'll look into jumpin the
service connector..

 

Click the codes link in my signature.

 

Back to drawing board. I grounded the D4 and got check engine back on, jumped service connector, but light won't spit out codes.. Going to have to trouble shoot while car has been stalling. I just replaced fuel filter , no go, next step, ? I'll keep plugging away..

 

Why would you ground the D4 wire and what in your mind is a D4 wire? Post pictures.

 

D4 wire is is located on the far right connection on a P28 ECU, bottom row second wire in from your left. Its for the Check Engine Light on your Dash, that gives OBD 1 codes.

 

You're doing it entirely wrong, and like I said, you're traveling from NY to NC via CA. Click the CEL Codes link in RonJ's signature, and do it the right way. While you're doing that, don't go back to the idiot mechanic that told you to **** with your engine harness just to pull a code.