4L80E transmission hot message
Thread Starter
Registered User
Joined: Feb 2020
Posts: 1
Likes: 0
4L80E transmission hot message I have a 4L80E transmission in my 2003 GMC 2500hd 4x4 6.0. I had a problem with the trans cooler lines rusting out and leaking losing a lot of fluid. I replaced lines and cooler and now have a "transmission hot" message coming up. My infrared thermometer says it is not hot, and I can hold the oil and of the dipstick in my hand comfortably. I have blown air through the lines to confirm flow. The message comes and goes, and the transmission shifts like it always has since new. Can it be a faulty sensor? Can I disconnect that sensor somehow? Will an ECM reset help? Any info would be greatly appreciated
TECH Junkie
Joined: Jun 2008
Posts: 3,203
Likes: 1,391
From: Nitro Alley
The 4L80E fluid temperature sensor is part the the internal wiring harness of the transmission.
Replacement of that sensor is actually, replacement of the internal wiring harness of the transmission.
Inexpensive and simple to replace.
Yes the temperature reading could be incorrect... It is possible that the sensor is no longer operating properly... just odd timing.
Or the replacement ATF cooler is not sufficient enough at lowering the fluid temperature.
Replacement of that sensor is actually, replacement of the internal wiring harness of the transmission.
Inexpensive and simple to replace.
Yes the temperature reading could be incorrect... It is possible that the sensor is no longer operating properly... just odd timing.
Or the replacement ATF cooler is not sufficient enough at lowering the fluid temperature.
