P0751 - 1-2 Shift Solenoid Valve Performance - No First or Fourth Gear

I knew I was having trouble with my tranny solonoid a......getting ready to dig into it.....thing that I wonder is why does the code say no 1st or 4th gear. The only gear I am having trouble with is 2nd......whats up with my box the 1st and 4th thing?

Sorry...it's early..should have said....

..whats up with the 1st and 4th gear thing?

The PCM is detecting the solenoid is not performing properly. According to my ATSG guide for the 4T65E tranny P0751 which is a class "B" DTC error code indicates 1 - 2 Shift Solenoid Performance problem. All shift solenoids work as a logic gate based on the signals received from the PCM. One not working could conceivably affect other shifting, etc.

P0751 does the following:

It disables shift adapts.
Commands maximum line pressure.
Inhibits 3 - 2 downshifts when speed is greater than 30 mph

Basically the 1 - 2 shift solenoid is sticking in the off position and should be replaced.

Thanks Bob....kinda figured it was what we already knew. You have almost got me talked into doing this myself. How much is that solenoid....and should I go ahead and do anything else while I am in the tranny? Oh......what about part numbers so I can order the stuff?