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Discussion Starter · #1 ·
I recently bought a 98 civic ex that originally had a auto transmission. It still has the auto wiring harness and the p2p a84 ecu. I have an extra p2p a12 for the manual ecu but it doesnt plug and play being that the p2p a84 auto ecu uses all four ports vs the p2p a12 manual ecu uses 3 ports. My question is what correct jumper harness do i need to buy to make this work correct. For any experts does it really make a difference changing auto to manual ecu as far as programmed shift points and what not and am i losing power running an auto ecu in a manual car? i swear this fresh y8 i dropped in should have way more power.
 

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I swapped the same car for my y7 trans/ecu/harness/engine. I didn't have to buy any jumper, but I needed to extend the o2 sensor (y7 harness). The car is super slow but it's because its nonvtec with a long geared tranny.
 

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Discussion Starter · #6 ·
are they both obd2a?





I just read all this info thank you very much. I will talk to a couple of friends helping me on the project and try and do the pin swap til i can either A get a manual wiring harness or B find the correct jumper harness to go from A/T p2p a84 to manual p2p 12 obd2b. I did a iacv delete cause of all the issues ive come across. Now that i have the pinout information i can fix the iacv issue aswell. Thanks
 

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BATSLOMAN GIVES NO FUCKS.
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if you look at the pics I posted and compare to what you posted, your bottom ecu is an obd2b from a 99-00.
you need an obd2a ecu for the correct plugs.
 

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I recently bought a 98 civic ex that originally had a auto transmission. It still has the auto wiring harness and the p2p a84 ecu. I have an extra p2p a12 for the manual ecu but it doesnt plug and play being that the p2p a84 auto ecu uses all four ports vs the p2p a12 manual ecu uses 3 ports. My question is what correct jumper harness do i need to buy to make this work correct. For any experts does it really make a difference changing auto to manual ecu as far as programmed shift points and what not and am i losing power running an auto ecu in a manual car? i swear this fresh y8 i dropped in should have way more power.
Please correct me if I am wrong... turns out the P2P-A84 To P2P-A12 is an OBD2A To OBD2B conversion, correct?
obd2a-harnesses used on 99-00 civic ex's manual transmission
obd2b-harnesses used on 96-98 civic ex's automatic transmission
Also, please if you have anything to add I'd like to know I'm currently doing this pinout procedure on my vehicle
Thank you
 
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