PWM cooling fan(s) control using ECM

[dontlifttoshift]

Originally Posted by mikels

While there has been several 'releases' of calibrations for the LS crate engines, the software has remained the same.

So enabling PWM fan control is matter of wiring properly and enabling in calibration.

Dave

Apparently this is not the case. PWM does not work with the GMPP controller we have either. Yes, it is wired properly. Yes, I turned on PWM with HPTuners. No, the fan does not operate with PWM.

Temporarily wired a relay and switched back to discrete while I come up with a solution. Probably will go the same route as JP did and get a new ECM and rewrite the calibration over. I would like to find a better solution than that, if it exists. I have a couple of installs coming down the pipeline where I would prefer to use the PWM control and the GMPP harness.

Dear GM,

That's pretty stupid.

Sincerely,
Hot Rodders

[andrewb70]

Originally Posted by dontlifttoshift

Apparently this is not the case. PWM does not work with the GMPP controller we have either. Yes, it is wired properly. Yes, I turned on PWM with HPTuners. No, the fan does not operate with PWM.

Temporarily wired a relay and switched back to discrete while I come up with a solution. Probably will go the same route as JP did and get a new ECM and rewrite the calibration over. I would like to find a better solution than that, if it exists. I have a couple of installs coming down the pipeline where I would prefer to use the PWM control and the GMPP harness.

Dear GM,

That's pretty stupid.

Sincerely,
Hot Rodders

Donny,

Thanks for the confirmation. I was pretty sure that JP wasn't being a dumbass...

It would be nice to know if there was a change at some point with the GMPP ECUs. Clearly some early ones worked, while the later ones do not. It would be nice to know when the change over took place.

It would also be nice to know if the change is hardware, firmware, OS, or something else. Maybe GM is selling so many of the ECU harness packages that it was feasible to make a dedicated (lower cost) ECU? Seems pointless, but I can see some bean counter saving $10 per ECU by removing the PWM driver (or whatever it might be called).

Andrew

[dontlifttoshift]

Originally Posted by andrewb70

Donny,

Thanks for the confirmation. I was pretty sure that JP wasn't being a dumbass...

Andrew

I didn't think so either, I was really hoping he had a faulty ecm along with some bad info from GM.

Mikels, if you see this and still have any connections, could you dig into this a little further and try to figure out what changed at what it takes to make it right?

[andrewb70]

Originally Posted by dontlifttoshift

I didn't think so either, I was really hoping he had a faulty ecm along with some bad info from GM.

Mikels, if you see this and still have any connections, could you dig into this a little further and try to figure out what changed at what it takes to make it right?

I have a really early GMPP (2008) ECU and harness kit. I'd love to implement this and also add a data point, but I don't have HP tuners...

Andrew

[mikentosh]

Originally Posted by vannatta20

Anyone have any luck getting PWM output from an E38 ecu with a camaro OS? No matter what settings I use it will not output a signal. If I use a truck OS I get a PWM signal easily. The truck OS does not see AC pressure. The car OS does. This is why I need to use a car OS. I used an oscilloscope to verify

This would explain the same issue I was having earlier. I was also working with an E38 out of a Camaro. Would love to hear a response on this as we are running the setup with discrete fans on relays now and its annoying

Originally Posted by mikentosh

Wondering if anybody has troubleshooting advice for the PWM signal coming from an E38 ECU? I'm not seeing any PWM signal coming out from X1 pin 58.

I took my multimeter and put black probe to DkGrn wire coming from X1 pin 58, and red probe to battery positive terminal, and set to DC volts. Turning key on I can see the voltage go up to about 1.2V but regardless of toggling fans and duty cycle in HP Tuners I don't see any change. I would expect to see either ~5V or ~12V across here but do not. I didn't even bother to switch my multimeter over to duty cycle measurement, but assumed without the higher voltage its not working.

Any ideas on further troubleshooting? Pin 58 is a ground PWM signal correct?

[gofastwclass]

Originally Posted by mikentosh

This would explain the same issue I was having earlier. I was also working with an E38 out of a Camaro. Would love to hear a response on this as we are running the setup with discrete fans on relays now and its annoying

What year Camaro?
I have a 10 SS with an E38 I'm willing to experiment on using HP Tuners as time allows.

[mikentosh]

Originally Posted by gofastwclass

What year Camaro?
I have a 10 SS with an E38 I'm willing to experiment on using HP Tuners as time allows.

Mine is out of a '13 1LE Camaro.

[andrewb70]

Originally Posted by mikentosh

Mine is out of a '13 1LE Camaro.

Mike, the signal is ground, so your volt meter needs the other side go to a hot +12v source. Are you doing that?

Andrew

[mikentosh]

Originally Posted by andrewb70

Mike, the signal is ground, so your volt meter needs the other side go to a hot +12v source. Are you doing that?

Andrew

Yup, this is how I was measuring it.

We have moved the whole motor and E38 setup into another truck and still have pin 58 with a wire tap ready, if somebody solves this. These last few comments have us considering flashing the OS on the computer over to the Corvette setup. Does anybody have pointers on how that can be accomplished with HP tuners?

[andrewb70]

If anyone needs a controller with the connector and a Yazaki connector for the power feed, send me a PM.

Andrew