99-02 E-Fan control

[1FastBrick]

I recently installed E-fans On a 99 GMC Sierra, The OS in the truck was 09373372. I activated the fan functions and set the temps accordingly.

When the engine was turned on The fans would come on even at a low temp and run constantly. I did have the correct bi-directional control when commanded Via the scan tool.

I verified the fan settings were correct, Tried another harness, and even programmed a different PCM believing that was the issue. I even tried a different a few different Operating systems. It wasn't until I specifically used a 2002 OS# 12212156 that the fan function's worked correctly.

Some one else did an 2001 silverado around the same time and was having the same issue. I told him about the 2002 OS I used and it worked for him too.


I am being told that when this change is made using Hp Tuners that it function's correctly and you do not need to swap Operating systems to get the fans to function correctly. I have not verified for my self but a reputable tuning company is telling me so as that is what they use to activate fan settings.


I am curious as to what's different in the older OS and why EFI Live could not make the changes to the older OS?

I was running the latest 2015 March update at the time.

My main concern is the Smog inspection as the new program checks what engine calibration the vehicle is using during the scan process as well as the vin#

[joecar]

I don't know the answer (could not discover that parameter in the older OS...?)...


Where are you located (what state are you smogging in...?)...?

[1FastBrick]

I don't know he answer (could not discover that parameter in the older OS...?)...


Where are you located (what state are you smogging in...?)...?

Smog Law requirements for the vehicle in question is for CA.

Not sure if you are familiar with there new Star program. But basically they are now looking for OBD2 systems that have been tampered with. Part of that is checking the Operating system and CVN numbers with Vin# against known manufacture specified numbers indicated for that vehicle year and model.

What parameters are you looking for?

G1203 set to Parallel Series Fans
G0106 set to Fan 2 Control

Temps speeds and pressures set accordingly for vehicle and Thermostat requirements.

I'm guessing it's something in the background that can't be seen. I'm just curious as to why the changes don't work correctly on older operating systems Vs. the specific 2002 system we had to convert to. I don't have any software or the understanding to read hex code, although I wish I did so I could write my own CAX files.

[joecar]

They don't have any OS/CVN data for vehicles prior to 2005/2006.

[1FastBrick]

They don't have any OS/CVN data for vehicles prior to 2005/2006.

Interesting...

Any Idea Why the changes work on the 02 OS Vs. an earlier OS???

[joecar]

I don't know why E-Fan did not work on the earlier OS.

[1FastBrick]

I don't know why E-Fan did not work on the earlier OS.

I wonder about something. On the older OS I was only re-flashing the change to the calibration.

I wonder if for some reason I needed to do a full flash like when I changed to a newer OS???

It has to be something simple even if it's in the background coding.


Any one with experience please chime in.

I am being told by another tuning company that has multiple Software, That they apply there Fan patches with HP tuners and it works correctly with out needing to swap to a newer OS. I will need to do this again in the near future So I am hoping that I don't need to send the PCM's out Or purchase HP tuners software for something that should be so simple.

[RADustin]

If you can get a read from a truck that is fixed correctly maybe efilive can look at it?

[1FastBrick]

Potentially, I could get one by sending the The next PCM out to be programmed as it is offered free in there service. I just pay the shipping.

I know in the Editor it will show the change, But I am not sure what would be different in the coding in the background or if it would even show the difference in the background. Maybe a PCM with the patch applied would be needed for testing???

I have heard something about possibly the pin polarity and that I would either need to apply the patch with HP tuners or finds some one with Tuner cat software to change it.

I would rather spend the money On EFI Live licenses and adding new streams Vs. the other software...