[TanTurd]

For whatever reason or another, I would like to change the radiatior turn on temperature. Yes, I believe the car is fine with the 223°F turn on temperature and blah blah emissions, but if I wanted to reprogram the PCM to adjust the temperature. Does it have to be done with a DRBIII or will something like a Autel MaxiSYS MS906 or LAUNCH X431 work? Or something less expensive..
Thank you.

 

[Ronbo]

Not Possible even with a DRB3.

 

[UmmScott]

Yeah sorry man.. you're not gonna be able to.

Unlocking software in these cars is very very difficult

Sent from my SM-G975U using Tapatalk

 

[TanTurd]

Ouch 😔 thank you. A temperature switch wired to fan relay is the only way then 🤔

 

[Ronbo]

Maybe wire an aftermarket electric thermostat of some type directly to the fan shroud assembly? Take the control away form the PCM. Not sure if the PCM would throw a fit not seeing the fans turn on when commanded. Need to look into that.

 

[Ronbo]

Looks like there's a couple of DTCs for Fan Control Monitoring. P0480/P0481. I would say you'd need to keep the stock connections directly to the stock fan control relays. But disconnect the relay outputs to the fan motors and install your own thermostat module. That way the PCM would see the coil activity of the stock relays and avoid the CEL and trouble codes. That's all theory and guessing though.

 

[TanTurd]

If I applied power through a separate relay to the fans and the factory relay receives power on the terminal but the coil isnt energized it shouldn't freak out the computer I'm thinking.. even if it gets energized for some reason, the positive to positive connection shouldn't hurt anything

 

[Ronbo]

The PCM verifies the Fan/Relay operation by the power draw on the relay coil. You would need to leave the stock fan relays and wiring in place for the coil side. You then disconnect the contact side wiring and put your own circuitry in.

 

[TanTurd]

What if I left the contact side so the fan could still function as intended for A/C, Trans Temp, etc. But added a separate relay for my add on temperature switch? Wouldn't that work?

 

[Ronbo]

I suppose that would work. Basically you'll have two different control circuits that meet at the fan motors. Remember there are High/Low Fan circuits and depending on car year the wiring/circuits are different.

 

[Ronbo]

And you realize that modifying the fan turn on won't make a huge difference without a lower temp thermostat?

 

[TanTurd]

Sounds like a plan. Thank you for your help
Yes, I replaced the Thermostat when I did the waterpump at 77k miles a few months ago. I'm going to give it a try in a week when the parts arrive, also replacing trans cooler with it's own fan and inline fluid temperature switch - it sprung a leak and decided go big or go home since its hotter than hot in Arizona and it down shifted hard a couple times when fluid temps were hot. I was hoping it would be easier to program pcm like with my supercharged Saturn I can change it with HPTuners and verify the difference in horsepower, timing, etc.
Thank you guys for your help!