2006 corvette fan ignoring hp tuner commands

Hi All,



Having an issue with a buddies 2006 supercharged vette that he bought. Long story short - the original owner told him the fan module was fried and had an aftermarket one wired up. We don't like the aftermarket one because it is sloppy and don't feel it cools as good. He would like to stay with the factory setup and so we are investigating the issue.



So here is what happens when he put in a used module:



Ignition on, key off I try and command the fan on with hp tuners = nothing
Ignition on, key on, fan comes on instantly on cold start up at full blast (AC not on).
Turn the ignition off and the fans remain on for a 300second run cycle.
IF I try and command the fans off any any time with the engine running or during the cool down cycle with hp tuners I get no response.
So in other words, the car is ignoring my pcm commands from hp tuners in the specialty tab using just the VCM



For shits and giggles we installed the previous controller module that the vette came with and the results are exactly the same.



Now, he has eliminated the plug and hard wired the wires from the pcm / power / ground as the hardness before the fan module (up by the subframe) is known to go bad, so that is also ruled out.



Looking at the tune which I am posting here I can tell the following:



The fans are set to come on at startup only after the car hits 168.8*F and only at 11%. Yet, at startup and well below this temperature they are on a full blast?
output control vs state is all set to "1" - I don't know what this function is or what those numbers mean. I thought I saw this tune as being stock as far as the fan settings go, but maybe I am missing something somewhere else? I am not over familiar with the vette tunes so it is possible I am over looking something when trying to diagnose this.


Other thoughts:



We thought maybe it was a PCM issue - but clearly the PCM is needed to command the fans on? But also how is it ignoring direct commands from Hp Tuners to turn on and off?
We thought maybe it is the coolant sensor, but it is reading the coolant temp fine
We thought maybe he got a faulty controller, but what are the odds both are bad and display the same symptoms? Usually when these are bad the fan just doesnt work?


We are both stumped at what to look at to diagnose. Obviously the fan works when plugged in, but not properly and not as commanded. All the issues we have read deal with the control module not working and causing the fans not to work.



Tune attached - thanks to anyone who can help out!Attachment 90051

with those fan settings they will be on at all times, if u can find another stock tune file copy over the "relay controls" both tables and the "control by %" ect table or u can move that one around to suit the temp u want each fan to come on at, or try these below see if it helps

https://i.ibb.co/qCRtSrf/fan-temp-settings.jpg

Is that graph from a 2006 corvette or a c5? I only ask because I don?t know the stock tune for this- and the one stock one I downloaded from the repository looked different?

with your settings id say yours is not stock and has been changed at some stage, these were from my 2007 LS2 fan settings

your setting are ok, the issue is with the enhance OS the temperature scale is changed

what happens when you command the fans off?

With the enhanced temp tables, the lowest temp setting is 0 so should the fans not come on when it is below that temp if it is 100f and the 165 table is set to 0?

Also why would it ignore my command on the vcm to be off?

I suggest to try both on and off in the VCM scanner.
to see if the control is opposite what the factory fans use. If the factory fans were replaced with some generic fan, the PWM control is backwards on some (not intended as direct replacement for the car)

Quote:

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Originally Posted by 5ft24

I suggest to try both on and off in the VCM scanner.
to see if the control is opposite what the factory fans use. If the factory fans were replaced with some generic fan, the PWM control is backwards on some (not intended as direct replacement for the car)

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I have tried commanding on / off with the vcm with no luck. I tried to command on with the engine off but key on and it ignored that as well.

My other issue is I can?t even try just changing the 165* setting to 190* to all 0?s since we don?t have credit for the car. I am just looking at the tune for him to try and help out but he had another tuner do the work.

I'm fighting my own battle against fan issues and making zero progress. One thing I noticed about the override controls is that if you are logging the fan on/off state and desired% while giving it manual commands, those logged readings never change. If the fan state channel is showing 'ON' and you command it 'OFF', the state never changes. I'm not convinced yet that the fan controls actually work at all.

Quote:

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Originally Posted by blindsquirrel

I'm fighting my own battle against fan issues and making zero progress. One thing I noticed about the override controls is that if you are logging the fan on/off state and desired% while giving it manual commands, those logged readings never change. If the fan state channel is showing 'ON' and you command it 'OFF', the state never changes. I'm not convinced yet that the fan controls actually work at all.

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I was having a similar issue with my car over the weekend...

Was in VCM scanner and no matter which "ON" command I sent to the car.. Fans would not turn on

Had a Burned up fan relay. Swapped it out and all is working again. Might want to take look and see if there is power present

Quote:

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Originally Posted by Jerry6

I was having a similar issue with my car over the weekend...

Was in VCM scanner and no matter which "ON" command I sent to the car.. Fans would not turn on

Had a Burned up fan relay. Swapped it out and all is working again. Might want to take look and see if there is power present

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I'm trying to figure out how to make an E40 control a C7 Vette brushless fan and there ain't no relay anymore! :cool: The wiring is identical to the OP's C6 PWM fan, but it uses different fan logic in the tune (EV instead of PWM) and instead of the C6's external controller, this one is built into the fan motor.

My doubt in the VCM Controls comes not from the fan not working, it's cause the channel 'Fan 1' shows 'ON' at all times even when commanded OFF. And, even with Fan 1 commanded ON at 0% the Fan Desired never goes to 0%. The logged channels don't show any change ever at all no matter what combination of buttons I poke at in the Fan Controls box. The measured voltage and duty cycle on the speed control wire to the fan also never change. Could be a dead output pin on this ECM causing my inop fan, but that aside the Fan Controls don't appear to do anything that I can see yet.

OK, the scanner controls work. Finally got my fan operating (it was a tune issue, though it shouldn't work with these settings) and the fan channels respond to the controls and change as they should.

How did you correct the issue?

And which relays are for the fans? I looked and did not find any relays? Do you have a pic of location?

My issue was that I'm swapping a C7 fan into a truck and had to find out the hard way that for whatever reason it won't work using the settings copied from a C7 tune file.

C6 has no relays, just the big Siemens module on the driver's side of the fan shroud. Diagram here:

Attachment 90301

If you need to try another fan controller look for one from a Ford Fusion, like 2006-2011 or something. Those are identical but dirt cheap, no 'Corvette tax' added...

I notice in your tune that the AC pressure sensor codes are disabled - any idea why? AC sensor affects fan operation just as much as coolant temp, if the car no longer has AC or if the sensor isn't in use you need to zero out the Fan Desired % vs AC table. That pressure sensor reading is active all the time, even when AC is off and the compressor is disengaged.

I would disable the after-run just as a matter of eliminating chances for it to do something weird, set time to 0s and enable/disable temps to max.

Quote:

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Originally Posted by blindsquirrel

I notice in your tune that the AC pressure sensor codes are disabled - any idea why? AC sensor affects fan operation just as much as coolant temp, if the car no longer has AC or if the sensor isn't in use you need to zero out the Fan Desired % vs AC table. That pressure sensor reading is active all the time, even when AC is off and the compressor is disengaged.

I would disable the after-run just as a matter of eliminating chances for it to do something weird, set time to 0s and enable/disable temps to max.

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Thanks blindsquirrel - zero'ing out this table got the fan to work as it should and follow the ECT temp table.

Two things still have us stumped.

1) The car still ignores the vcm commands for fan on/off
2 When we could cold start the car and run it for 20 seconds and shut it off and the coolant temp is 60* - the fans will come on for whatever the run time is (was 300s). Is there not a way to set this setting up so that if the Vette is over xx temperature then the fan comes on for set amount of run time upon shutting the ignition off? Right now we have set it to 0 and it does not come on after we shut the vette off, but we would like to have a number in here to help cool the car when it hits 200+F and we are parking it.

The manual override thing could just be a VCM Scanner issue specific to your ECM/OS combo. There are several glitches like that on mine I've opened support tickets for, but unresolved as yet. It's just stuff they have to go in and add in some future version. In my case there are sensors present that don't appear in the available channels list, sensors that are in the list but don't read correctly, etc. If you have/can get one, try a Tech2 (or MDI, whatever), those have manual output controls too and may work where the scanner doesn't yet.

Even though I have a different ECM and different fan, mine did the EXACT same thing when after-run was still enabled, even dead cold. Fan would be off before key-off, but then kick on again after some random time, speed up, stop, wait a few seconds, kick on again at a different speed, so on. I just killed it, happy to have finally made it run at all.

Something you can test to see if it has an effect on the after-run - in the table Output Control vs State, instead of all 1's, set the 0 column to 0. I did this and the fan still operates normally when running, but I haven't re-enabled after-run yet to see if it fixed that.

Quote:

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Originally Posted by blindsquirrel

The manual override thing could just be a VCM Scanner issue specific to your ECM/OS combo. There are several glitches like that on mine I've opened support tickets for, but unresolved as yet. It's just stuff they have to go in and add in some future version. In my case there are sensors present that don't appear in the available channels list, sensors that are in the list but don't read correctly, etc. If you have/can get one, try a Tech2 (or MDI, whatever), those have manual output controls too and may work where the scanner doesn't yet.

Even though I have a different ECM and different fan, mine did the EXACT same thing when after-run was still enabled, even dead cold. Fan would be off before key-off, but then kick on again after some random time, speed up, stop, wait a few seconds, kick on again at a different speed, so on. I just killed it, happy to have finally made it run at all.

Something you can test to see if it has an effect on the after-run - in the table Output Control vs State, instead of all 1's, set the 0 column to 0. I did this and the fan still operates normally when running, but I haven't re-enabled after-run yet to see if it fixed that.

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Here is a stupid question though - the output control vs state table is all 1's stock - does the fan on these cars come on anytime you shut the car off from factory? (I am not familiar with these vettes and my buddy bought his used/modified already) - If in stock form the table being all 1's doesn't cause the fans to come on when dead cold when you turn the engine off, then I am not sure I am confident that will resolve the issue. I will give it a shot next time I am out there though.

No, in stock form the fans don't run key-off unless the temp is above the set point(s). But stock it didn't come with the 2-bar custom OS, either.

BTW mine also has the custom OS, same weird behavior.