domestic_rice

I've always been under the impression that obd2a cars HAVE to have an obd2a harness and the same went for obd2b. But I heard that back when I was 16. It's been a long time since then and I'm kind of questions the bs that I had been just believing for years.

I've been looking all over and I can't find a clear answer. I have several obd2a harness and ecus and jumpers. I also have two obd2a cars and three obd2b cars. My question is why can I not use an obd2a engine harness on a obd2b car? Yes, there are extra plugs on the ecu side. Besides from that I see no difference. Especially if I'm using an obd1 engine with an obd1 jumper harness.

As of right now the pump isn't priming. Makes sense (what I've always heard) but my question is why. And what are the steps involved with converting? Is it as simple as the harness has a different pin out on the ecu plugs? If so, I'll just go ahead and convert. I'd just like to know if there is something I've never known about which is the real reason why you HAVE to match the harness with the car.

The car has an obd1 engine in it and when I use the correct obd2a harness it turns on and runs like a champ. I'm just trying to figure out what all is involved with making a mismatched harness work. Because I'd like to have more options when it comes to buying harness. I'm ok with switching/converting plugs (obd2 to obd1, I know that the plugs are the same with the obd2a/b. Converting is obd1-2. With the obd2's it's probably just the pin out) so if I need to do anything I'm ok with that. Any help will be greatly appreciated.

Thanks.

jdmadam

iTrader: (2)

I've seen many people try to convert and just gave up. It can be done but its not worth it. Always use the same type of harness that came with the car for a nice easy clean install. But if you want to give it a try then I suggest you get all the ecu pin-outs and cabin harness diagrams for both obd2a and obd2b cars. Good Luck.

PariahBoardshop

I second searching for pinouts. That is all you need. I started chasing an ecu problem and ended up properly rebuilding my engine harness.

domestic_rice

Thanks for the info. I was thinking it was something like that.

I'm guessing the pin outs are mixed around on both the ecu side and the driver side of the engine harness? If so that doesn't seem too bad. I'll time myself today and see how long it takes and see if it's worth it or not.

Thanks.