1990 F250 4.9L E40D trans was recently replaced with national rebuilder unit and I have a hard shift into 2nd gear. I ran KOEO test and I'm getting codes 31 (EVP/PFE Low) and 98 (EPC Driver) Keep alive code is 15 .... I have replaced egr valve ,MAP, Oxygen sensor and also noticed before changing, the egr valve was badly clogged as was the o2 sensor with carbon buildup. The end of the tube from the exhaust to the egr was also showing some buildup at end of tube which was since cleaned. Is there anything you can make of these codes I supplied you with and recommend something before I revert to sending this rebuilt trans back? Your help is greatly appreciated.......

 

Can anyone help this bloke???? I know nothing about auto except that they have red fluid, filters, and bands in them.

 

Codes 15 (memory) and 98 (hard failure) point to Powertrain Control Module (computer) problems. 31 means low voltage in the EVP circuit. I would disconnect the plugs at the computer and transmission. Look carefully for any bent or corroded pins. If ok, reconnect everything and test again. Since transmission fluid pressure is controlled electronically, PCM problems could cause hard shifts. Disconnect the battery before pulling any of the plugs. The engine may not run well for a while after the battery is reconnected until the computer re-learns the engine.

Jim

 

hey, i had that code 31 forever and could not figure it out. i already had replaced the egr itself and then i bought a new sensor for the top of it as well as the "regulator". my mechanic fixed it (and he has done this several times) by tacking on a little extra to the "prong" that rests on the egr diaphram. no more code now. i think he just touched the end with a braizing rod or somehting; basically welded on about 20 thou to the end of the "prong". can't help you with the rest sorry.