Whats going on I have a 99 civic dx 4cly 1.6 and i have a code P1509 the code is fault 2 in the IAC, the car at idle runs like crap and is running lean. i unpluged the IAC and it got better so i changed the IAC but it was the same. i checked the conector the goes into the IAC the Y/B wire and i have 12.8v so i ame getting power my O2 is switching a little slow but when i shoot some carb spary in the engin the O2 changes so thats ok my longterm is at 0% and the shortterm is at 6% when i put the car in drive it gets a little better but i am lost help


Modified by transporter2840cc at 6:35 PM 2/15/2004

 

I assume that your vehicle surges at idle correct?
you will most likely need a ECU. But you will need to verify if it is the ECU.
You will need to check duty cycle on these wires blk/blu, pin 3 and orn, pin 1. you should get anywhere for 10 - 50% duty cycle at no load(radio, headlights, defroster, blower,ect. off). if not within the percentage, meassure voltage at those wires. if your getting batter battery voltage 12.5 - 14.00 at idle you will need a ECU.