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P04 Coolant Fan routine

Posted: Fri Oct 27, 2023 2:53 am
by ProfessWRX
Any chance somebody has disassembled the cooling fan logic and can share it with me? I understand there are many OSs but the general idea will let me quickly trace any differences and find possible issues. I'm too far out from being able to do it all by myself still and have an issue with the cooling fans that seem to be ignoring the settings I'm able to change.

I have the fans turning on at 86C both high and low. I have the fans turning on at key off for 2 minutes if ECT is over 90C or so.

Low fans are turning on, high fans are not. After key off also doesn't work.

I've THOROUGHLY gone through the entire electrical circuit and can find no faults. That leaves only the PCM not doing what I say and that means the logic or some parameters for my car haven't fully been 'setup' in universal patchers database.

Re: P04 Coolant Fan routine

Posted: Fri Oct 27, 2023 3:05 am
by ProfessWRX
Or are there 2 ECT inputs to the PCM? I can only see one in the Logger but that would make a TON of sense.

Re: P04 Coolant Fan routine

Posted: Fri Oct 27, 2023 5:12 am
by kur4o
bcm controls the fans.

There is a setting that switch between bcm or pcm fan control.

It is called class2 fan control or something.

Re: P04 Coolant Fan routine

Posted: Fri Oct 27, 2023 5:29 am
by ProfessWRX
kur4o wrote:bcm controls the fans.

There is a setting that switch between bcm or pcm fan control.

It is called class2 fan control or something.
Awesome, so if I uncheck that it should switch to PCM?

Are there any other controls I can put back on the pcm?

Re: P04 Coolant Fan routine

Posted: Fri Oct 27, 2023 5:57 am
by kur4o
NOt sure there is any other control handled by bcm. This one switch all control of fan logic to pcm.

Re: P04 Coolant Fan routine

Posted: Fri Oct 27, 2023 7:01 am
by ProfessWRX
kur4o wrote:NOt sure there is any other control handled by bcm. This one switch all control of fan logic to pcm.
That was it! One less issue to sort out. Funny I had tried that switch but didn't stay on that bin file long enough to notice.

Thanks!