polything

P1509 = Manf Cntl Veh Spd Idle Speed Control Auxillary Inputs

I did a tranny swap, y7 to y8 intake manifold swap, 3 wires to 2 wires IACV, changed ECU to manual one...
But I still have P1509 cel.
How do i resolve this?

PICS:

polything

anyone?

Mr.Quang

iTrader: (2)

If you are using that P2E ecu in the picture, than there was no need to swap to a 2 wire IACV. 96-98 CX, DX, LX all look for 3 wire IACV's. The only reason to use a 2 wire IACV is if you use a 96-00 EX ecu or any OBD1 ecu. Swap your ECU wires back and plug in your 3-wire IACV connector into the throttle body mounted IACV. Reset your ECU and that P1509 code should go away.

polything

I no longer have the TB mounted IACV. The IACV valve is mounted behind the intake manifold (y8).
Also, im positive that I have NO vacuum leak.

Mr.Quang

iTrader: (2)

Ah i see. The P2E ecu is still looking for a 3-wire IACV. 2-wire IACV and 3-wire IACV sensors are not interchangeable even if you swap the wiring around. They both work in different ways.

polything

^anybody second that?

polything

anyone at all?

polything

???

polything

anyone?

polything

Howdy Honda Tech?

polything

????

Mr.Quang

iTrader: (2)

Are you using a manual Civic CX, DX, LX P2E ECU?

-If yes, than it is looking for a 3-wire IACV sensor ONLY, located on the throttle body.

-If you are using any OBD1 ECU, B-series ECU, or manual OBD2 Civic EX P2P ECU, than it is looking for a 2-wire IACV sensor located on the back of the intake manifold.

-2-wire and 3-wire IACV sensor is dependent on the choice of ECU.

From your original post, it reads to me that you simply swapped from Auto to Manual with a Y8 intake manifold and a OBD2 Non-VTEC ECU.

If this is true, than there is no reason to go to a 2-wire IACV.

Put all of the IACV related wiring back to factory. Use your Y7 throttle body with the Y7 throttle body gasket (it will leak if you do not use a Y7 gasket). Plug in the 3-wire IACV connector to your 3-wire IACV sensor. Leave your 2-wire IACV on the back of the intake manifold and leave it unplugged. Reset your ECU and the code will go away and your IACV will be fully functional.

-If you do not wish to take off your Y8 throttle body, find your Y7 throttle body and unscrew the 2 phillips screws on the green 3-wire sensor. Pull the sensor off the Y7 throttle body, plug the sensor into your 3-wire IACV connector and zip tie it somewhere. Reset your ECU and the code will go away, but you will not have a functional IACV. It will most likely idle low when the motor is cold, but will run fine when it is warmed up.

peeweezy

whoa...what a minute im getting the same P1509

i have the 3 wire plug into the one by the throttle body and also theres the 2 wire plug on the other piece on the manifold

SO WHAT YOURE SAYING IS FOR ME TO ERASE THE CODE ALL I DO IS LEAVE THE 3 WIRE SOCKET PLUGGED IN AND THE 2 WIRE SOCKET UNPLUGGED??

how does that work? i dont understand. why would honda make it so that only one of these plugs has to be plugged in???

FYI i have EX body with D16Y7 swapped in running P2E 5 speed ECU

peeweezy

well i went and unplugged the 2 wire socket on the iac thing and tried erasing the code with my scanner and it came right back and then i unplugged the 3 wire one and left the 2 wire one in and tried and still CEL on WTF

i dont even know what to do anymore

polything

Are you using a manual Civic CX, DX, LX P2E ECU?

yes, so all i need now is a p2p ecu, since i dont want to go back to 3 wires, and y7 tb.

peeweezy

yeah im using P2E ecu it still giving me crap!!

does this mean i have to replace the idle air thing on the back of my manifold?

polything

This is exactly what happened and how to fix it.
I had the wrong ECU.
So I decided to go back to 3 wires and y7 tb+IM.

THANK YOU MR. QUANG!