ISC Idle stepper valve idle diagram

[Elpizer2]

Hi guys.

I am running an AEM EMS v1 1g in my 1g FWD

My problem is that I see no changes into the idle settings.

I want to test the wiring or the ECU. So How the ISC Stepper motor works? how the OEM ecu handle it and how the AEM EMS V1 make it work?

I have a 93 wiring. It used to work nicely with jdm vr4 ecu + Maft. however when I upgraded to AEM V1, this has been a headache

 

[steve]

There are descriptions of the ISC/IAC in the DSM Technical manual (DTM) and the FSM you should read.

In short the ISC is a stepper motor, the center two pins are fed 12v and the ECU switches the outer pins in sequence to ground to make the pintle step in or out. Inside the factory ECU there are two M5269L IC's that are used to pull those 4 pins to ground in sequence causing the motor to step. I don't know what the AEM uses if anything to drive the ISC.