My 1999 Durango 5.9 has a check engine light in with the p1765 and po753 code, I've checked voltage at the pcm I have 12 volts at pin 30 5 volts at pin31 my question is isn't pin 30 supposed to be ground?

 

ok so I've bypassed the really in the fuse box under the hood and the Durango shifts fine now however my check engine light came back on after clearing the codes and now has the following codes po720,po743,po753 and p1765 any ideas?

 

You need to hook the relay back up. You now have battery voltage running to the trans constantly.

P0720 Output Speed Sensor Error
P0743 Torque Converter Clutch Solenoid/Trans Relay Circuit
P0753 Trans 3-4 Shift Solenoid/Trans Relay Circuits
P1765 Trans 12 Volt Supply Relay Control Circuit (42RE, 46RE, 47RE)

 

Pin 30 will show 12 volts because you are reading the voltage thru the relay.
The PCM provides the ground on that pin when it comes time to turn the relay on.
If you never see ground there, the relay will not be turned on.
In that case, there is either a problem in the PCM or the circuit that tells it to energize the relay.
You should not see any voltage on pin 30 if the engine isn't running.

Also, if you leave the relay bypassed, you will have a dead battery.

 

Ok so I've reinstalled the relay I've also replaced the pcm now it shifts great ran it down the road and now I get po720 code and the check engine light is on, should I replace the speed sensor? The speedometer is working at all speeds and I ran an onboard real time diagnostic and it reads the same as the speedo