Does anyone know the trigger temperatures for the Fan clutch?
- Thread starter zaid3ssaf
- Start date
Blckshdw
Moderator
What model year was that? Or even better, what calibration if you have it?!? Seems like they altered the operation a good deal while trying to iron out the troubles.
Blckshdw
Moderator
I have an 05 4.2 EXT. Not sure about the calibration, if you can tell me where to find that, I can look it up and share it.
Reason for my asking is I know they fiddled with the fan control quite a bit trying to get it right. So I imagine your values might be different then some earlier or perhaps later years??
Thought just maybe your tuner software may have mentioned the calibrations. There are like 6 of them in the PCM. The fan control is part of the "system" module. The numbers are accessible from a couple of paths. Mode $09 data is one and we can also grab them using mode $3C, "read data block". Without diving into other apps or having you tap into a serial terminal we can use Torque Pro. This entry as a custom PID will display the calibration number of the "system" module for us.
(Had to do a quick edit as I named the PID wrong at first try!!)
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Blckshdw
Moderator
I also have OBD Fusion. Good app.
I see your listing shows the verification number instead of the calibration number??
Here is what mine shows...
Something odd with both of my 2002 PCMs is that with both of them they have gibberish for the Electronic Throttle Control Calibration number when read from $09 data (the last in the group). The data is good in the Data Blocks as read by mode $3C. I thought it was just my TrailBlazer but then I pulled a PCM from a junkyard truck and it has the same thing.
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aaserv
Member
I dont know anything about Bravadas but I do know the original fan speed settings on the 03/04 Envoys were updated via a software update from the factory due to overheating problems. I think 05 and up have the newer settings.
Do you know what the settings are? I am wondering if the desired fan speed can be read through a PID similar to what the Tech2 can.
aaserv
Member
The settings have been discussed multiple times and a search for this site and google should give you more info than you will want.
A few things I remember off hand.
The speed called for and actual speed will vary due to a host of circumstances.
The speed is calculated through the computer and does not go by coolant temp alone. It tracks coolant, transmission temp and A/C head pressure, etc and comes up with the desired speed. Which is why they had to do a software update to correct the problems. Its not as simple as the coolant temp = so many rpms.
There is always a difference between called for speed and actual speed. The 6cyl having less difference than the V-8s, again for reasons I dont recall..
Its actually a very complicated system that gets even worse with aftermarket fan clutches that rarely can keep up with the constant changes from the computer.
A few things I remember off hand.
The speed called for and actual speed will vary due to a host of circumstances.
The speed is calculated through the computer and does not go by coolant temp alone. It tracks coolant, transmission temp and A/C head pressure, etc and comes up with the desired speed. Which is why they had to do a software update to correct the problems. Its not as simple as the coolant temp = so many rpms.
There is always a difference between called for speed and actual speed. The 6cyl having less difference than the V-8s, again for reasons I dont recall..
Its actually a very complicated system that gets even worse with aftermarket fan clutches that rarely can keep up with the constant changes from the computer.