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It was supposed to be an odb2a harness. Does not fit in the "a" port of ecu. The other plugs fit in c and d.
Originally Posted by tony_2018
Car information, what car did the harness come from. and what are you trying to do.
My car is 96 civic ex 5 speed. D16y8. The motor stamp said p2j5, which I heard means the motor came out of a 98 civic auto. My harness, ecu, and dizzy that is in my car is an odb2b. I bought an harness from a guy. I thought it was odb2a because it has the "d" plug. When I try to plug the harness into the odb2a ecu I just bought the "a" plug doesn't fit. The "c" and "d" plug fits though. It can't be an odb2b because it has a "d" plug and not the "b" plug.
Last edited by Former User; 10-09-2015 at 07:39 AM.
Reason: Car information must be placed in first post
If this is a civic harness that you are referring to, identifying the model year is simple.
If there are TWO grey plugs, one blue plug and the green crossover plug, it is OBD2A ('96-98).
If there is only ONE grey plug, one blue plug and the green crossover plug, it is OBD2B ('99-00).
Note: The "HX" engine harness is OBD2A style no matter what year it is... '96-00.
Basically you can't mix and match 96-98 and 99-00 engine harnesses with 96-98 and 99-00 chassis without also changing out the cabin harness. There's no jumper that'll fix it. Only time you can use a 96-98 ECU in a 99-00 chassis or vice versa is with an adapter harness.
If this is a civic harness that you are referring to, identifying the model year is simple.
If there are TWO grey plugs, one blue plug and the green crossover plug, it is OBD2A ('96-98).
If there is only ONE grey plug, one blue plug and the green crossover plug, it is OBD2B ('99-00).
Note: The "HX" engine harness is OBD2A style no matter what year it is... '96-00.
Not necessarily true. I have two grey plugs on my odb2b harnesses. And the other one I have looks like odb2a but the a plug doesn't fit.
I want to make it all odb2a because my chassis is 96 and I've heard you will never have your car running right if you don't have the right harness dizzy and ecu that goes with that year car. Well 96 to 98.
My apologies... I should have been more clear. I assumed you had a working knowledge of your chassis and left out the obvious difference between a MANUAL engine harness and an AUTOMATIC engine harness. AUTOMATIC Civic ECU's have pins in all FOUR plug locations. This means that the bulk of the auto trans related wiring is found in this fourth plug, which is located at position "B" on the '96-98 OBD2A style chassis and located at position "D" on the '99-00 OBD2B style chassis.
Long story short - you have a '99-00 AUTOMATIC engine harness with two grey plugs, one blue plug and the green crossover plug. The fourth grey plug would be found inside the car under the dash completing the process of filling all four plug slots on the ECU...
My car is 96 civic ex 5 speed. D16y8. The motor stamp said p2j5, which I heard means the motor came out of a 98 civic auto. My harness, ecu, and dizzy that is in my car is an odb2b. I bought an harness from a guy. I thought it was odb2a because it has the "d" plug. When I try to plug the harness into the odb2a ecu I just bought the "a" plug doesn't fit. The "c" and "d" plug fits though. It can't be an odb2b because it has a "d" plug and not the "b" plug.
There's your problem, you bought an engine harness that is not for specifically for your car.
There's your problem, you bought an engine harness that is not for specifically for your car.
No. Smart guy. I bought the car (that is still running) and didn't realize it had the odb2b ecu harness and dizzy. And I'm not asking someone to solve a problem. I'm asking if anyone knew what plug that is. If you don't have the answer, in which you don't, then keep your smart as remarks to yourself.
My apologies... I should have been more clear. I assumed you had a working knowledge of your chassis and left out the obvious difference between a MANUAL engine harness and an AUTOMATIC engine harness. AUTOMATIC Civic ECU's have pins in all FOUR plug locations. This means that the bulk of the auto trans related wiring is found in this fourth plug, which is located at position "B" on the '96-98 OBD2A style chassis and located at position "D" on the '99-00 OBD2B style chassis.
Long story short - you have a '99-00 AUTOMATIC engine harness with two grey plugs, one blue plug and the green crossover plug. The fourth grey plug would be found inside the car under the dash completing the process of filling all four plug slots on the ECU...
You are still not making sense. You just said 99 to 00 have the plug in position "d". I have an odb2b harness in my car right now and there is nothing in "d". And my question about the plug is not even that harness. I have another harness and it has the plug I don't know what it is. I know what the cabin or dash plug looks like. The plug almost fits into the "a" position but doesn't. Though it is closest to firing the "a". Not "b" not "c" not "d" not cabin or dash.
Ok, lets see if I can explain this to you differently. OBD2A and OBD2B ECU's have four plug slots in them... three are used for manual transmission cars, and all four are used for automatic transmission cars. The "automatic" plug is the "B" plug on the OBD2A ECU... and the "D" plug on the OBD2B ECU. With respect to the ECU's themselves, a manual ECU will not have any pins in the above mentioned locations, yet the automatic ECU will in fact have pins in all four plug locations.
The top ECU is an OBD2B and the one below it is the OBD2A... both are manual, so you can easily see the pin-less plug locations at "B" and "D". Now, if you look closely at this photo, you will see a slight difference in the plug shape in the upper right corners of the "B" and "D" plugs between the two ECU's. This difference exists so you cannot insert them into the wrong ECU accidentally and fry stuff.
Now, to loop back to my previous post. Lets assume for a moment that you have an automatic '96 civic. The engine harness would have all four ECU plugs (3 grey and 1 blue) at the end of it along with the green crossover plug. The '96-98 manual engine harness would have 1 LESS grey plug on it.
Now, if you had a '99 automatic civic, the engine harness would have only three plugs on it, two grey and one blue. The fourth grey plug would be found under the dash with the chassis side of the green crossover plug. Again, the manual version of the OBD2B engine harness would gave one less grey plug on it as well.
This is where I believe your confusion in identifying the engine harness exists. Manual '96-98 engine harnesses and '99-00 automatic engine harnesses both have three plugs on them, but they do not interchange between ECU's. If you have both OBD2A and OBD2B ECU's, plug the harnesses into each of them so that you can see what I am describing.
I appreciate you trying to explain this to me. The harness I have the issue with plug "a" won't fit into either one of my ecu's (odb2a or odb2b). The harness that is in my car now (odb2b) fits into my odb2a ecu. If I could figure out what harness I have for the unknown harness I could possibly use my "a" plug from my odb2b harness and put it on my odb2a harness so all three ecu plugs fit my ecu.
Look at this photo for reference.
10-07-2015, 04:57 PM
