IAC Waveform Question and Neat Observation

This is an IAC motor waveform for a 98 Chevy Blazer vin ‘W’ 4.3L. IAC is a 4-wire stepper motor. Looking for second opinions that I can file this as “Known Good”. Only reason I ask is because the tops and bottoms are not perfectly flat as they appear in Paul’s book.

Neat observation though (as it appears to me):
Setup: This is a snapshot of a “KEY ON” event (KOEO)
Channel 1 = COIL A HIGH Control
Channel 2 = COIL A LOW Control
Channel 3 = COIL B HIGH Control
Channel 4 = COIL B LOW Control

Looking at the voltage spikes at the top of the green trace and the bottom of the blue trace….If you look to the left of the frame divider (position 160) you can see where COIL A (channels 1 & 2) is/are “in the lead” as compared to COIL B (channels 3 & 4). This is the IAC motor winding the pintle down extending it towards the pintle seat in preparation for start-up. At position 160 you see where the pintle has stopped because it has contacted the seat. Then to the right of 160 you see where the field reverses and COIL B “takes the lead” as the pintle retracts. At least I think that's what is going on.

Though not shown here, when I turned the key off COIL B was “in the lead”. The pintle only retracted (did not extend) as the module put the pintle in position for the next “KEY ON” event. Kinda cool I thought.

Bumpity, bump. Just looking for an experienced thumbs up that these IAC traces look good even though the horizontal parts aren't perfectly square. Thanks Folks!

I think what you see is just the effect of the inductance of the coils.

Agreed, I'm OK with the flats not being quite... flat. Looks like a known good, IMO.

That looks just like the example waveform in the book, "Automotive Oscilloscopes, Waveform Analysis."

So I'd say it a good waveform.