Ok connected them either way just so I knew it wasent that that was wrong. Thanks for the advice though!

 

Tested it with the multimeter. It only reads 1.2volts when I complete the circuit with the multimeter. Gonna be the wiring then I'm guessing. right?

 

My engine (B18C) uses 2 wires to actuate the IACV. The Yellow/Black (ignition power) and Black/Blue (ECU sink output or ecu switched ground).

So when the key is ON and the plug is disconnected (or connected I guess), the Yellow/Black should have 12+ volts between it and Ground at all times. The Black/Blue wire is the ecu control wire that 'sinks' to ground when the ECU wants to turn on the idle air control valve.

 

Sorry, I left this off.

The hard part about taking a DMM reading between Yellow/Black and Black/Blue is that we are not certain when the ecu wants to open the IACV (when it switch Black/Blue to negative). That's why I resorted to using an LED indicator.

While unplugging the IACV allows access for DMM readings, this also tells the ecu that the IACV is not functioning (because its unplugged) and it may (not certain) stop sending its signal via Black/Blue.

If you have leads that can be pressed into the backside of the connector (without unplugging it) to take measurements from, this may help get accurate readouts.

Oh, I know, its annoying. Thats why I said f-it and ran a temporary indicator light.

 

^^^this is correct. dont worry about measuring between the two wires on the plug.

yellow/black = power
black/blue = ecu (b23)

thats all you need. the ecu provides a switched ground which varies the voltage of the iacv controlling how much it opens.

 

Dident wire the LED but checked IACV wiring all the way to ECU and it still throwing check engine even after I reset it.

 

you dont need any LEDs. just do as posted above and you will be fine.

1 wire to power, 1 wire to b23. if you are lost in the wiring harness, just run new wires.

 

Agreed, my LED was simply for convenience. It is unnecessary unless you have 100,000+ of them of the shelf at your disposal...

So,

#1 Do you have +12V on Yellow/Black (while ignition is ON)?

#2 Do you have continuity (~0 ohms) between B23 and Black/Blue (at IACV side)?

#3 If (1) and (2) are Yes, then its the ECU or IACV and not wiring.

Sorry, had to go for a while...

#4 If all answers are yes, The easiest way to check the Output of the ECU B23 pin is by utilizing an Oscilloscope to check the signal (to see if it is being 'sunk' to negative by the ecu). Next easiest (in my opinion, took me all of 3-4 minutes) is by running an indicator in parallel (ergo my LED approach). Another possibility is using a multi meter (voltage setting) on the ecu B23 pin (black node) and +12 volts (red node). Each time you see +12 on the DMM screen, you know that pin B23 is pulled to negative. If any of the above choices shows that the node is pulled low intermittently (while the ecu wants to actuate the IACV), then the ECU is functioning appropriately.

Note: I DO NOT KNOW THE DUTY CYCLES OF THE IACV. ("intermittently")

Yields the result that the IACV is probably the problem.

Please note, my concept of 'easiest' is obviously biased to my available resources. Questions, comments, concerns welcome.