MSefi.com read only forum (Jan.15,2018)

I'm having trouble getting the IAC motor to function. Engine is a small block ford with BBk 70 mm throttle body. I read the manual several times for the correct settings as well as install the diode between the two wires. The unit is a pwm two wire. I understand from a little bit of research no board modifications are required. I am getting 12 volts to the throttle body but do not get any response from the IAC motor at all. I have adjusted the megahertz setting from 80 to 800 in increments of 80. I am not sure if the unit is wired to the relay board incorrect. I understand that the motor works with a decrease in voltage to change position. No getting a change in voltage or change in motor position. There does not seem to be a lot of information on this in the manual yet as the ECU is still newer. Any help would be great.

Just to add to the previous post.... I have still been looking for information on this issue. I found something under MS2 extra hardware manual.

V3.57 PCB, this is a little tricky so care must be taken. Fit the TIP122 and solder a wire to the base of it and to the right side of R19, next to U8. Then connect the Collector to SPR1 (you can use any of the db15 pads if you wish) and the emittor of the TIP122 connect to a GND pad on the V3.57 pcb. This will give you the FIdle valve output on pin 3 of the db37 connector (or what ever connector the pad you used is connected to), do not use the standard FIdle output connector on pin 30 of the db37. The TIP122 can be mounted on the case or in place of R37 on the heatsink if R37 is linked out, remember it MUST be insulated!

On DIYAutoTune, the description for V3.57 stated that this modification was not necessary. Both sources seem to have reliable information but they are contradicting in this case. I think I am more confused that I was before.

We do not recommend this modification; I've used a V3.57 to drive the IAC valve directly before. We recommend a frequency of 320 Hz, it's closest to the factory frequency of 300 Hz. The higher the duty cycle, the further it opens.

Thanks for the info Matt. I will give it a shot!!!