E38 spal PWM control issues

[twistedtx]

I know this is a dead horse but after looking through all of the posts and tech I still cant figure out what is wrong with my wiring/tuning. Recently installed aftermarket brushless spal fans on my buggy. I wired them exactly like spal instructed. The E38 ecm is running the OS from a 2014 Camaro and per Alldata I have tried pin 17 and pin 58 on the black connector. Those pins are labelled low speed and high speed fan control. I have tried every combination I could find for the tune and I have not anything that was able to get ANY type of signal out of those two wires. I have a spare ECM from when I was racing and it does the same thing. There must be an easy solution is what I keep telling myself but I cant seem to find it. I have attached the tune file and keep in mind I don't know which combination this tune has. I have a hard time giving up and buying the spal control when the ecm should control it. any help would be greatly appreciated! 10-11-23 mk car1.hpt

[blindsquirrel]

Unable to open file.
This file is part of a Remote Tuning network that you are not part of.

Aftermarket SPAL and the stock ECM have inverted duty cycle - max % commanded at the ECM would be max speed with a GM SPAL fan, but would be OFF with the aftermarket. And ECM commanding OFF or minimum speed should be full or high speed with the aftermarket fan.

Apply the main power & ground to the fan harness, but leave the signal wire disconnected. Does that signal wire, coming from the fan side, have ground or +12v on it? If it's ground, and you apply +12v, does the fan run? Or, if it has +12v and you ground it does the fan run? Would be kinda silly diagnosing an ECM issue if the fan itself didn't work.

If you can prove the fan works I'd say you are really going to need an oscilloscope to look at what kind of signal the ECM is putting out - if any. It would really help if other people were able to see what's in the tune file.

[blindsquirrel]

...even if you manage to get a valid PWM signal out of the ECM, I don't recommend the combo of stock ECM with aftermarket SPAL fan because of the inverted duty cycle thing. Use a GM SPAL fan, or use a standalone controller.

https://www.ebay.com/itm/143561646769 + aftermarket SPAL fan
or
stock ECM + 1518914 600W 14" / 1518927 850W 19"

[twistedtx]

...even if you manage to get a valid PWM signal out of the ECM, I don't recommend the combo of stock ECM with aftermarket SPAL fan because of the inverted duty cycle thing. Use a GM SPAL fan, or use a standalone controller.

https://www.ebay.com/itm/143561646769 + aftermarket SPAL fan
or
stock ECM + 1518914 600W 14" / 1518927 850W 19"

I have inverted the table values already with no luck.
when wired up and ready to go the white wire shows 12v and I get nothing when applying ground to that signal wire. I grounded the fans to a chassis bus bar but its a phenomenal ground with direct connection to the battery via a secondary 4ga cable. I have 4 of these fans in the shop at the moment and I have yet to see one of them turn under their own power. Bench test also didnt work with 100% brand new fans.

I tried to attach the file? does it not show up on your end?

[twistedtx]

10-11-23 mk car1.hpt

maybe tune file will show up now.
is it common for an ECM to not be able to provide the correct signal?

[blindsquirrel]

I see the file, and I download it, and when I try to open it it pops up a window containing the text

Unable to open file.
This file is part of a Remote Tuning network that you are not part of.

You'll need to remove the remote tuning stuff from the file so your settings can be checked. Only after the settings are correct does it make sense to move forward with things like looking at the ECM output signal with a 'scope.

[blindsquirrel]

How are you checking to see if it works? Are you doing it at key-on, in the scanner's special functions menu? Have you commanded different %'s, and put a test light on the signal wire (clipped to ground won't show anything, the ECM pin switches between open circuit and ground so clip test light to B+)? What tools do you have available? Have any friends who own a 'scope?

[blindsquirrel]

Is the control wire on the fan-side of the plug at ground or +12v, with power/ground applied to the fan's big fat wires? Seems like I have asked this before and it got skipped over like most of the other questions I asked.

How about if you answer my questions and then, based on your answers, I provide some direction for where to go next, instead of jumping from one 'butwhatabout...' to the next. Okay?

[blindsquirrel]

This is a C6, but still E38 and the control side is the same. Control pin switches between open circuit and ground, has no pullup inside. If 'Number of Fans Fitted:' is '1' then it uses only C1/X1 58. Pin 17 is only used if Number of Fans = 2. So stop thinking about pin 17.

screenshot.15-10-2023 17.04.41.png

This is what the output looks like when commanding 15% fan:
pwm electric 128hz 15 percent.png

...and when commanding 44%:
pwm electric 128hz 44 percent.png

The other fan table for A/C Pressure also needs to be dealt with especially since this is one of those inverted-duty-cycle things and also if this is some kind of swap that isn't using an A/C pressure sensor.

[twistedtx]

Is the control wire on the fan-side of the plug at ground or +12v, with power/ground applied to the fan's big fat wires? Seems like I have asked this before and it got skipped over like most of the other questions I asked.

How about if you answer my questions and then, based on your answers, I provide some direction for where to go next, instead of jumping from one 'butwhatabout...' to the next. Okay?

Okay, Ill try to follow step by step for clarity if anything else. I had no idea there was any remote tuning protection in this tune and I hope I have removed it now. 10-11-23 mk car1.hpt

On the bench and on the car I have the big fat wires connected to battery directly. the control wire is 16ga white wire (shows 12v prior to me doing anything) and I have applied ground and 12v power to this circuit without any success. I am using a powerprobe do do all of this testing. Not being able to fire the fan on the bench is driving me crazy. I have more than your average mechanic's resources but admittedly most of my tools are old school.

I have been testing the control function via Hp scanner and turning on the fan with the key on. I have tested those wires for ground, power, and HZ(fluke meter) and I have not been able to confirm any of those functions working. I have not done an actual heat cycle yet because starter issues but I should be able to do that shortly after wrapping up some other wiring.

I do not have a scope but I have sent the message out to my friends and I may have one by tomorrow.

I figure I have two hurdles at this point. fans not bench firing and ECM not sending the signal. I dont mind using a stand alone controller however it is just another thing to add to an already incredibly tight car and another thing to fail. If these fans would just come on I would feel much better lol.

[twistedtx]

I have done nothing with the AC tables at all so that could be part of the issue.

[blindsquirrel]

I've seen other Camaro OSes that were originally relay/discrete fans that would not do a PWM output no matter what settings were used. That was on a 2011 and I was able to find a Corvette file with the same OS ID and swap in the 'System' segment, and it then worked.

Problems here are:
- no way to verify whether there's a PWM signal coming out, other than 'it doesn't work'. That's not good enough to say one way or the other.
- by 2014, Corvettes were D.I. and using E92 so I don't know where a donor for the segment swap would come from. 2014 CTS-V is E67. 2014 Caprice is E38 but a different OS ID.

I suppose, since all the 2011-up E38s had a single Service Number, you could swap it out to a 2011 Camaro OS, which is probably easiest/cheapest to just get another ECM pre-programmed to a 2011 VIN. Unless you have the stuff to do SPS flashing yourself. It can't be reflashed to a different year like that in HP Tuners even if you wanted to spend the credits to license a different file (8 segments in the ECM but HPT only reads/writes 6 of them).

Brett from SPAL has posted here in the past, and somewhere described the defaults for the different fans' control strategies. I believe it was in another of those extremely frustrating "I bought the wrong fans and have no choice but to keep digging the hole I'm in please help" threads.

[twistedtx]

I've seen other Camaro OSes that were originally relay/discrete fans that would not do a PWM output no matter what settings were used. That was on a 2011 and I was able to find a Corvette file with the same OS ID and swap in the 'System' segment, and it then worked.

Problems here are:
- no way to verify whether there's a PWM signal coming out, other than 'it doesn't work'. That's not good enough to say one way or the other.
- by 2014, Corvettes were D.I. and using E92 so I don't know where a donor for the segment swap would come from. 2014 CTS-V is E67. 2014 Caprice is E38 but a different OS ID.

I suppose, since all the 2011-up E38s had a single Service Number, you could swap it out to a 2011 Camaro OS, which is probably easiest/cheapest to just get another ECM pre-programmed to a 2011 VIN. Unless you have the stuff to do SPS flashing yourself. It can't be reflashed to a different year like that in HP Tuners even if you wanted to spend the credits to license a different file (8 segments in the ECM but HPT only reads/writes 6 of them).

Brett from SPAL has posted here in the past, and somewhere described the defaults for the different fans' control strategies. I believe it was in another of those extremely frustrating "I bought the wrong fans and have no choice but to keep digging the hole I'm in please help" threads.

For the record, pin 58 has given absolutely zero action. it has never changed one single time regardless of my settings. That leads me to believe there is something internally wrong in the ecm.

I will contact spal in the morning to verify the fan is good and how to test them.

the stand alone controller you linked above is a little hard to figure out. does it trigger according to basically any type of signal you want to send it? then provides the PWM signal out according to the settings selected? its much cheaper than the spal unit and currently available. have you used that unit and had good experience?

[blindsquirrel]

The add-on thing is triggered by a sensor, either a separate sensor or the existing ECT. It does not use any kind of PWM input from another module. It's just a standalone fan controller.

If you change the tune's fan settings back to Discrete, and command Fan 1 on/off, does pin 58 change state? Hard to give more exact suggestions without a way to know if there is a PWM signal present at that pin or not.

[twistedtx]

The add-on thing is triggered by a sensor, either a separate sensor or the existing ECT. It does not use any kind of PWM input from another module. It's just a standalone fan controller.

If you change the tune's fan settings back to Discrete, and command Fan 1 on/off, does pin 58 change state? Hard to give more exact suggestions without a way to know if there is a PWM signal present at that pin or not.

I just changed to discrete and attempted to trigger a change with HP scanner.
I had no connectivity prior to ignition and once i keyed the car on it went straight to ground. I could not get the scanner to change the state of the wire. After turning the key off for several seconds it would go back to no connectivity.

[blindsquirrel]

Did you revert to all the stock 2014 Camaro fan settings, or just leave the other 3 or 4 tables as-is and expect it to work by only flipping the one Fan Type setting?

[twistedtx]

Did you revert to all the stock 2014 Camaro fan settings, or just leave the other 3 or 4 tables as-is and expect it to work by only flipping the one Fan Type setting?

I honestly figured that setting disregarded the other tables. so yes that's exactly what I did. Could you point towards that tables that need changing?

[TheMechanic]

I honestly figured that setting disregarded the other tables. so yes that's exactly what I did. Could you point towards that tables that need changing?

If you have the stock file or a stock file that is like vehicle just load your file and then load a compare file and use the ctrl+5 to see the comparison log. You can use the copy over selected to fix, or at least see the differences between the two. Great tool.

[twistedtx]

I got the fan to run on the bench and can do so with the diagnostic wire. it takes several seconds with power applied for them to do anything and that's why I couldn't confirm they worked prior.
I have now done a segment swap in the system section of the tune with a stock tune file. I compared it to several tunes and it matches the settings on all tables from a stock file with this OS. Pin 58 still does nothing but stay grounded while the ignition is on. Do I need to be doing a "write entire" flash?

[blindsquirrel]

Would it be possible for you to post this latest file you've made changes to?