RPM occasionally fluctuates with AC Compressor on

[ac427]

Just taking a quick look and not having read all 7 pages. How does the ecu determine the effort needed to maintain idle?

I believe there maybe a separate map for when the A/C is engaged. Would the A/C pressure sensors come into play?

[Bry5on]

Just taking a quick look and not having read all 7 pages. How does the ecu determine the effort needed to maintain idle?

I believe there maybe a separate map for when the A/C is engaged. Would the A/C pressure sensors come into play?

The DME estimates a torque request from the AC compressor, it actually translates this as a number over the CAN bus (or was it D bus?) and uses this to set at least the throttle relative opening target as the revs fall to idle. I don’t think it would cause hunting, unless maybe the AC compressor clutch was slipping? Hmm.