Hello
I need diagnostic help on my 2000 F150 4.6 4R70w trans. All trans operations work correctly once or twice a day. Then there is no 2-3 up shift. Manual downshift to 2 works all the time and will get me home.

Did an electrical diagnosis and found that the PCM wire that controlls the SS2 (shift solenoid 2) has 12 volts with key in the run position. It should only have voltage for the 2-3 shift.

Checked the SS1 and the voltage was correct for the 1-2 shift. Checked the resistance on the PCM harness wireing that had to do with the transmission and everythink was OK.

Replaced the PCM, with no change on trans operation.

Help.
RAYBURGH

 

https://www.ford-trucks.com/forums/7...-3rd-fine.html


http://www.supermotors.net/getfile/1...ssembled98.jpg

 

Thank you.

Does a bad solenoid account for having 12V present with key on? There must be a feedback in the trans someplace. Remember I replaced the PCM and the nothing changed.

RAYBURGH

 

ALL PCM controlled solenoids and relays have 12V positive sent to them at all times,the PCM controls the grounding of those devices for control purposes.
JL