IAC is the toughest part.
Dual Coil Solenoid IAC Control
Found in some BMWs (Bosch) along with Toyota & Subaru, These have three pins, one of which is common, one is a solenoid that opens the idle valve, the other is a solenoid that closes the valve. If neither coil is activated the valve remains in a 50% open poisition (preset-spring type), or moves freely between opened/close position (no spring type).
EC36-pin6 to IAC close pin EC36-pin17 to IAC open pin
Configuration
Set IAC actuator speed/pwm freq
stepper speeds : 0 - 976 steps/s, 1 - 488, 2 - 326, 3 - 244, 4 - 195, 5 - 163, 6 - 139, 7 - 122, 8 - 108, 9 - 98, 10 - 89, 11 - 81, 12 - 75, 13 - 70, 14 - 65, 15 - 61.
pwm freq: 0 - 244 Hz, 1 - 195, 2 - 163, 3 - 139, 4 - 122, 5 - 108, 6 - 98, 7 - 89, 8 - 81, 9 - 75, 10 - 70, 11 - 65, 12 - 61, 13 - 57, 14 - 54, 15 - 51.