Fan on/off temperatures

[EDZIP]

Setting "fan on" temps via TunerPro is understood, just wondering - how does the 16188051 pcm communicate to turn the fans off?

[steveo]

electrically? there's no need for an 'off' signal, the fan relays are momentary. sends 12v to the relay for on, removes it for off.

in the tune? the temperature is a threshold, not a min-max type value. above the temperature, they're on. below, they're off. it has a hysteresis value to widen that threshold so they don't turn on/off repeatedly if temperature is hanging around that value.

[lionelhutz]

I'm not following your question. The PCM controls the fans directly so it doesn't need to communicate with anything.

[EDZIP]

I'm not following your question. The PCM controls the fans directly so it doesn't need to communicate with anything.

Steveo got it

"in the tune? the temperature is a threshold, not a min-max type value. above the temperature, they're on. below, they're off. it has a hysteresis value to widen that threshold so they don't turn on/off repeatedly if temperature is hanging around that value"

So "hysteresis values" are calibrated with specific time line values instead of specific temperature ranges?

[steveo]

So "hysteresis values" are calibrated with specific time line values instead of specific temperature ranges?

https://en.wikipedia.org/wiki/Hysteresis#In_engineering

[steveo]

(the first one is applicable)

[lionelhutz]

The hysteresis adds the temperature band instead of their being separate on and off temperatures. For example, put 5* in for hysteresis and it turns off 5* lower than it turns on.

[EDZIP]

Great info...are hysteresis values adjustable within the 16188051 environment?

[steveo]

'Fan Coolant Temp Hysteresis'

[EDZIP]

'Fan Coolant Temp Hysteresis'

Thanks guys...another good day in life...learned something new.