$OE 16197427 fan code

[Nasty-Z]

Tried using the code here :http://www.gearhead-efi.com/Fuel-Inj...=E-fan+control


Fan controls , temp on and temp off seem to work fine , only thing that seems out of the ordinary is the A/C request fan on command , if I press the A/C switch on the control panel in the dash , the fan turns on as it is supposed to with an A/C request , but if the A/C switch is pressed again , the fan will continue to run , well past the 45 second delay in the code . When is it supposed to turn off ?

SixShooter seemed to have the same thing happen here when he tested it years ago and is referenced in this thread : http://www.fullsizechevy.com/forum/g...code-0d-2.html Post 22 .

Other than that everything seems to be good.

Thanks in advance

TOM

[JeepsAndGuns]

I am running that code on mine and don't have any issues. But I do not have A/C, so I don't think I'll be of any help.

[sturgillbd]

If the vehicle is not up to operating temperature (lets say ECT of 125F), does the fan cut off when the a/c is cut off via the pushbutton on the dash? What temp thermostat are you running and what are the fan on / off temps? I looked at the code last night and also a few mins ago. This code doesn't seem to care whether the fan was cut on via the temperature routine or the a/c routine. It reads temperatures and the fan state.The way I understand it to work would be: If the fan is first requested by A/C and the A/C was then shut off with the temperature above the cutoff temp but below the turn on temp, the fan will continue running until the cut off temp is reached and the minimum run timer expires. Someone correct me if I'm wrong... Hopefully this post makes sense

Brian

[Nasty-Z]

Thanks for the replys all,

If the vehicle is not up to operating temperature (lets say ECT of 125F), does the fan cut off when the a/c is cut off via the pushbutton on the dash?

Just tried that , started @ 71 degrees on the T/P display , started the truck , tapped the A/C request button , fan came on , tapped the button again and the fan stayed running , well past the 45 second timer in the code . It was approaching 100 degrees and the fan had not yet shut off , shut the truck off and restarted and the fan was off until the desired on temp was met .

What temp thermostat are you running and what are the fan on / off temps?

180 degree Stant Superstat , 198 degree on temp , 188 degree off temp . 215 Degree overheat temp . Seems to like these just fine .

I looked at the code last night and also a few mins ago. This code doesn't seem to care whether the fan was cut on via the temperature routine or the a/c routine. It reads temperatures and the fan state.The way I understand it to work would be: If the fan is first requested by A/C and the A/C was then shut off with the temperature above the cutoff temp but below the turn on temp, the fan will continue running until the cut off temp is reached and the minimum run timer expires. Someone correct me if I'm wrong... Hopefully this post makes sense

Exactally what I was thinking , but it dosent seem to work that way I suppose .

I'm going to check the code again to be sure I have it entered the correct way .

Thanks for the replies

TOM

[sturgillbd]

This could be an issue where the $0E mask hasnt had the reverse engineering $0D has. There may be some other code with the transmission etc that is causing it to get latched. One thing to try would be add the address L0151 to the datastream and dash to see if the timer is counting down after the A/C switch is cycled on and off. There was a thread about dual fan code on FSC where they found the memory location was being used by another routine and it was getting clobbered. The thread about the variables and memory locations is here: http://www.fullsizechevy.com/forum/g...n-code-0d.html Post #2.
Relevant statement by helo: Edited to correct bug with using 0150/0151 for timers. 0250/0251 seem to be unused (then again, that's what I thought about 014f-...) I added E-fan control to my jeep but havent wired it in yet. I may have to set up a test bench to make sure the patch I put in will even work.

I will post what I find.

Brian

[Nasty-Z]

This could be an issue where the $0E mask hasnt had the reverse engineering $0D has. There may be some other code with the transmission etc that is causing it to get latched. One thing to try would be add the address L0151 to the datastream and dash to see if the timer is counting down after the A/C switch is cycled on and off. There was a thread about dual fan code on FSC where they found the memory location was being used by another routine and it was getting clobbered. The thread about the variables and memory locations is here: http://www.fullsizechevy.com/forum/g...n-code-0d.html Post #2.
Relevant statement by helo: Edited to correct bug with using 0150/0151 for timers. 0250/0251 seem to be unused (then again, that's what I thought about 014f-...) I added E-fan control to my jeep but havent wired it in yet. I may have to set up a test bench to make sure the patch I put in will even work.

I will post what I find.

Brian

Don't know if posting my .bin would help , but it is attached . Perhaps someone with a test bench can verify operation.

I just tried the setup again , started the truck and let it run to the fan turn on temp , fans turned on but when the temp reached the fan off temp the fans kept running .

This test was without touching the A/C , it seemed that once Pin E3 was commanded to ground , either by using the A/C request command or the fan on temp being reached , it would not release or un latch , either by the fan off temp being satisfied or the A/C request being turned off . The only way to "reset" , if you will, was to shut off and restart the truck.

I apologize from my statement above where I said it was working good with the on/off temps I posted , somehow I assumed the fans had turned off when I quit for the night last night , whereas that was not the case. It had been a long night......

I do appreciate the help !!

TOM

[sturgillbd]

Tom,
Here is your bin with the timer variable moved from L0151 to L0251. This should be quick test to see if the memory location is causing the problem. You can do a bin compare from your bin to the one I edited to see the changes. Should just be 4 byte locations changed. The change should be from a 01 to a 02. If this works, the memory location 0151 is used by some other routine. It will probably be later on in the week before I can set up a bench to test what is happening with the original code or what is happening in general if this doesn't work. I will also have to borrow a friend's Megasquirt Stimulator. It will make it much easier to vary the temps etc.
Let us know the results.
Brian

[Nasty-Z]

Tom,
Here is your bin with the timer variable moved from L0151 to L0251. This should be quick test to see if the memory location is causing the problem. You can do a bin compare from your bin to the one I edited to see the changes. Should just be 4 byte locations changed. The change should be from a 01 to a 02. If this works, the memory location 0151 is used by some other routine. It will probably be later on in the week before I can set up a bench to test what is happening with the original code or what is happening in general if this doesn't work. I will also have to borrow a friend's Megasquirt Stimulator. It will make it much easier to vary the temps etc.
Let us know the results.
Brian

Brian ,

I will try to give this a try later tonight or tomorrow . Thanks , I appreciate it !!!

EDIT **** - Works like a charm , A/C turns fans on and off and temp on / off works like it should.

OK, In laymans terms , the 4 changes that were made , where and what did it do ? Just so I understand.

Thanks

TOM

[sturgillbd]

The 4 changes were just the memory location to which the minimum fan timer count is stored. It seems as though the problem was two different things in the ecm were trying to use the same spot to store a number. The original address was L0151. Others had problems using L0151 and the other guys found that memory locations L0250 and L0251 didn't seem to be used. I just changed the code in your bin to use the L0251 address for storage of the MFR variable. Look at the code from http://www.gearhead-efi.com/Fuel-Inj...=E-fan+control At the top of the $0E section it shows the ram locations.
Ram Variables:
L0283 = MPH
L00A8 = Coolant Temp
L004D,BIT 0 = A/C STATUS (1 = A/C Requested on)

L0052,BIT 3 = Fan Output Control
L0151 = Minimum Fan Run Timer <-- Changed all references of this to L0251

I'm glad it worked because I was thinking earlier I cannot fully bench test the code for your situation. I cant simulate the 4L80E on the bench and the transmission code may be what caused the issue. I really don't know. I was in the process of adding the two memory locations to datastream to see what the values were doing when the code was running. 1project2many had done this on a VSS issue a while back and I was going to attempt to try the same method with your issue if this didn't fix your problem.

Brian

Edited fan code is as follows :

7100: 19 b9 b1 aa 2d 00 00 00 00 00 00 00 00 00 00 00
7110: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
7120: ce 71 00 12 52 08 1f 96 a8 a1 01 22 11 12 4d 01
7130: 06 96 a8 a1 02 23 37 b6 02 83 a1 00 22 30 14 52
7140: 08 a6 04 b7 02 51 b6 02 51 26 16 12 4d 01 06 96
7150: a8 a1 03 23 09 b6 02 83 a1 00 22 02 20 10 15 52
7160: 08 b6 02 51 d6 02 c4 f0 26 04 4a b7 02 51 4f 5f
7170: 39