4l80e always reads -38

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Sep 10, 2018 | 04:19 PM

Crysis

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4l80e always reads -38

I have a 99 4l80e and its been reading -38 all the time I already replaced the sensor what can this be??

Sep 10, 2018 | 06:57 PM

truckdoug

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From: Portlandia

-38 what? fluid temp? is the 80e native to your vehicle or is it a swap, altered harness? it could be wired wrong.

Sep 10, 2018 | 07:25 PM

Crysis

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Quote:

Originally Posted by truckdoug

-38 what? fluid temp? is the 80e native to your vehicle or is it a swap, altered harness? it could be wired wrong.

Yeah its swap I did the sloppy mechanics 4l80e harness modification and blew up the first 4l80e which had trans temp working put this one in and hasn't been working

Sep 10, 2018 | 08:14 PM

rpturbo

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What exactly is "blew up the first 4l80e?" Less is not more when asking for help

Sep 10, 2018 | 08:19 PM

Crysis

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Haha its a turbo 5.3, the transmission wouldn't shift anymore after some pulls

Sep 10, 2018 | 08:36 PM

truckdoug

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From: Portlandia

is the internal trans harness wired as before?

Sep 10, 2018 | 08:43 PM

Crysis

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What do you mean?

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Sep 13, 2018 | 08:52 PM

Darth_V8r

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-38 DA? -38 degrees latitude? -38 dollars in checking account?

Sep 13, 2018 | 08:59 PM

#10

G Atsma

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From: Central Cal.

Quote:

Originally Posted by Darth_V8r

-38 DA? -38 degrees latitude? -38 dollars in checking account?

And here I thought I was the only one in the dark...

Sep 13, 2018 | 10:34 PM

#11

truckdoug

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From: Portlandia

Quote:

Originally Posted by Darth_V8r

-38 dollars in checking account?

he said he's got an 80e, not a 60e

Sep 13, 2018 | 11:01 PM

#12

G Atsma

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From: Central Cal.

No mention in this thread of a 4L60E....

Sep 13, 2018 | 11:18 PM

#13

pdxmotorhead

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From: PDX-OR-USA

Well it evens out,, there is no real problem description either.. LOL
So I'll say -38 is way off... should be more like +237

Sep 14, 2018 | 01:05 AM

#14

Crysis

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Staging Lane

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Come on what else is -38 obviously temp, you guys gotta be kidding if you don't know just don't reply don't try to be smart or funny, i felt it was pretty obvious what i meant

Sep 14, 2018 | 10:23 AM

#15

G Atsma

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From: Central Cal.

-38 is WAAAAY below freezing. So it ain't temp, dude.

Sep 14, 2018 | 11:46 AM

#16

truckdoug

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From: Portlandia

the trans fluid temp pressure modifier table goes down that for guys that live in canada.

its a resistive sensor so you need to verify it's getting the 5v it needs and the return signal is going to the right pin on the pcm. missing either will make it read -38 temp. I went thru this with the older 80e I use in my turbo truck. my fix was to delete the trans temps sensor DTCs

Sep 14, 2018 | 12:30 PM

#17

Crysis

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Oh so does urs still read like that? And yeah its getting 5v

Sep 14, 2018 | 12:53 PM

#18

truckdoug

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From: Portlandia

No, I can't log anything at all. It wont come up in channels. There is nowhere for it to acquire data.

I only did that so my trans tune segment would not try and adjust shift pressures for it being cold as ***** (technical term for -38ºF)

What is the output from the sensor reading in voltage? probably somewhere in the 2-2.5v range at like 80º --just a guess.

If the sensor is getting 5v and you're getting an output voltage then the problem lies in the signal return to the pcm. Either the trans pinout is wrong or a connection isn't being made somewhere.

I'm not sure what pin gets the temp signal...you'd have to look on lt1swap.com for that probably