04 sierra 4L80e shifting problems
#1
04 sierra 4L80e shifting problems
what's up guys I have a 2004 sierra 2500hd 6.0 with a 4L80e tranny, same thing as a chevy haha. It's throwing the code P0502 (vehicle speed sensor low input) I changed both speed sensors, 1 on the transmission, 1 on the transfer case, problem is still there. Changed the fluid and filter too. Also has abs light saying all 3 abs sensors circuit malfunction, and service brake system light is on. It's shifting really hard, it's in fail safe boosting line pressure to max. Just wondering if anyone has had a similar problem. It shifts smooth in 4wd though, shifts hard in 2wd and shifts too early.
#2
the code is for the output speed sensor...which is the one on the tcase
at this point check the continuity of the wiring from the pcm to the sensor.
-key off, unplug the speed sensor and pcm connectors (conncector c2 pin 20 green black and pin 21 purple white wire
-ohm check the wiring for high resistance, opens, short to grd
at this point check the continuity of the wiring from the pcm to the sensor.
-key off, unplug the speed sensor and pcm connectors (conncector c2 pin 20 green black and pin 21 purple white wire
-ohm check the wiring for high resistance, opens, short to grd
#3
Thanks for the reply, even though it’s a year later. I was able to fix that problem but now a year later the code is back as well as the symptoms. If all sensors are new and wiring is intact, is it a possible there is a mechanical problem with the transmission?
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