How can get out of limp mode on 4l60e tranny - 2003 GMC Sierra

May have gone into limp mode read link below
https://www.700r4transmissionhq.com/4l60e-wont-shift-into-overdrive/
https://www.700r4transmissionhq.com/how-to-fix-limp-mode/


https://www.youtube.com/watch?v=pbaj0dOG2vg
https://www.youtube.com/watch?v=JPtbECZI-z8

https://www.youtube.com/watch?v=KW7PhRlOLG

Mean transmission is gone.

Some cars require a code scanner which will read trans codes to re-set this.

Bypassing the neutral safety switch won't help with the transmission problem. That switch is only wired into the start circuit.
Scan the computer for trouble codes. Has to be a code if it is in limp-in mode.

The first thing to check is the wiring to the transmission. You could have a short in the loom. Haveyou tried to pull DTC's?

dont do a peel out

Are you sure its stuck in first gear, Its probably in second.. It sounds like a stuck or open shift solenoid in the tranny (4L60E hydra-matic). Depending on the year and type of tranny this was a default setting to either only second or only third gear, should some electrical or transmission hydraulic fault occur. Another common problem for that year is a faulty ignition switch at the key cylinder. It will fail and not send power to the tranny (thus not powering up the shift solenoids). The default (or limp home mode) is when both solenoids are commanded off. They will be both commanded off in second gear (even when the tranny is operating normally).

Before you buy a new tranny, get a second opinion. It sounds like a stuck or open shift solenoid in the tranny (4L60E hydra-matic). Depending on the year and type of tranny this was a default setting to either only second or only third gear, should some electrical or transmission hydraulic fault occur. Another common problem for that year is a faulty ignition switch at the key cylinder. It will fail and not send power to the tranny (thus not powering up the shift solenoids). The default (or limp home mode) is when both solenoids are commanded off. They will be both commanded off in second gear (even when the tranny is operating normally).

your truck is in limp mode,
have someone check the output and input sensors on the transmission

Sounds like the tranny control circuit needs to be replaced. It may just be the wires that go from ECM to tranny control module