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Hello, I'm kind of a newb with the LS platform tuning. I am currently attempting to finish my E-fan upgrade. I have successfully got the fans installed and wired up with a 3 wire pressure sensor and was able to get the fans to come on at the desired temperature. Where I have ran into a problem is that I need to change the A/C type which is not an option in the current xdf that I have using in tunerpro. I have tried to compare the 12216125 bin to the 12212156 bin to try and find exactly needs to be changed but have had no luck. I do know that the 02 Firebird/Trans-Am use the type of A/C system that I need in my bin and that people are using my os in those vehicles to use flex fuel but haven't found a way to change it. I am a certified mechanic and not a computer programmer so dissecting code is something that I know nothing about. I know I can change the type with HP tuners but was hoping to not have to go that route. The ecu is seeing the correct pressure from the sensor I just believe it doesn't know what to do with it until I change the type. I got all my information from this post https://www.performancetrucks.net/forum ... ol-553385/ . If someone could help me identify what code needs to be changed or an xdf with a/c type defined it would be greatly appreciated.

Thanks,
Jeremy

vr4play wrote:Hello, I'm kind of a newb with the LS platform tuning. I am currently attempting to finish my E-fan upgrade. I have successfully got the fans installed and wired up with a 3 wire pressure sensor and was able to get the fans to come on at the desired temperature. Where I have ran into a problem is that I need to change the A/C type which is not an option in the current xdf that I have using in tunerpro. I have tried to compare the 12216125 bin to the 12212156 bin to try and find exactly needs to be changed but have had no luck. I do know that the 02 Firebird/Trans-Am use the type of A/C system that I need in my bin and that people are using my os in those vehicles to use flex fuel but haven't found a way to change it. I am a certified mechanic and not a computer programmer so dissecting code is something that I know nothing about. I know I can change the type with HP tuners but was hoping to not have to go that route. The ecu is seeing the correct pressure from the sensor I just believe it doesn't know what to do with it until I change the type. I got all my information from this post https://www.performancetrucks.net/forum ... ol-553385/ . If someone could help me identify what code needs to be changed or an xdf with a/c type defined it would be greatly appreciated.

Thanks,
Jeremy

Not sure, but I believe what you want is at address 0x1EFB4 in the binary, so have a look in your 122 16 125 XDF for that address and see if it's in there, if it is, it's already defined or I'm wrong, if not then you can edit it in the binary.
The value at that address in the binary is most likely 01 currently, you would want to change it to 00.

Opps, editing in the binary may cause a checksum error, that would need to be clarified by some one else ...

Gampy, Thank you for your reply. I opened up my hex editor with a stock bin and a modified bin and made some changes in tuner pro and found that the 00 or 01 at address 0x1EFB4 is the A/C auto re-circulation byte. I already had that one changed in Tuner Pro to 00 fan 2 output. I'm looking for the AC type to change from Analog cycling to Analog so that it knows there is a High pressure sensor not a switch. I have a suspicion of 0x1EFC4 and that needing to be changed from 03 to 02 but that would be me just guessing based on what I've seen and how things change.

Edit: Note that this change turned out to be for OSID 12212156. Do not use this for 12216125!

I think the one you want is 1E686 change from 03 to 02. At least I did before and after bin reads from making the change and that is what happend (also segment checksum add 1E520 and add 1 to match the subtract one in the other area)

antus, thanks for the reply. When I open my bin I have a 00 at 1E686. I don't quite understand what you mean about segment checksum and add 1. Does that mean I would just increase the value at 1E520 by 1? I have added the bin from my truck if you wouldn't mind looking at it. Thanks

BTW I believe you can use Universal Patcher to fix the checksum ...

And using Universal Patcher, it says your original file already has a failed checksum for the System segment.

Checksums:
OS Checksum 1: A36B [OK] Checksum2: 6553 [stock]
EngineCal Checksum 1: 622C [OK] Checksum2: 602D [modded]
EngineDiag Checksum 1: DD9D [OK] Checksum2: 1A48 [stock]
TransCal Checksum 1: E4A4 [OK] Checksum2: 822A [stock]
TransDiag Checksum 1: B1C8 [OK] Checksum2: 9670 [stock]
Fuel Checksum 1: 7D59 [OK] Checksum2: E7CB [stock]
System Checksum 1: 26BA, Calculated: 25BA [Fail] Checksum2: 92A8 [modded]
Speedometer Checksum 1: 3368 [OK] Checksum2: 2F57 [stock]

Damn phpBB using Proportional fonts in protected blocks sure makes a mess of things ... Insane!

Here is a bin that I have not been messing with in hex editor. It passed all the checksum checks in Universal Patcher. I only modified this one in Tuner Pro.

Did you try the change Antus suggested, then used UP to correct the checksum ??

I'm finding 0x1EFDA
00 - serial
01 - serial cycling
02 - analog
03 - analog cycling
04 - Passive
05 - not fitted

and 0x1EFB4
00- fan #2 control recirc
01- ac recirc

Looking at Irondukes address (1efda) in the binary and what is around it, it looks like the more likely suspect, I would try it first.