The trans on my 2002, 2.4L, Camry started to slip. I searched car-part.com for a used replacement. After doing a part search using the VIN number, I found a low mileage trans about 160 miles from me and bought it. My original trans was a U241E and replacement turned out to be a U241 from a 2004. During the installation process I noticed that the neutral safety switch plug did not fit my harness. I was able to get my original switch back and finished the job. As soon as I got on the road, the problems surfaced. The car did not want to shift and was bogging down during acceleration. After talking to a few techs, I could not get a straight answer to the cause. Some said the trans is bad, and the others said the ECU is not reading the trans correctly. I'm not sure who to believe, but a ECU replacement or reflash sounds a lot easier than swapping the trans out again. Anyone with a similar issue, and hopefully a resolution?

 

Make sure the wiring is correct, if computer is unable to access the shift solenoids it goes into a default mode. If it is unable to access them all it goes in high gear.

Does the trans seem to be in high gear?

Determine what happens when the gear shift lever is used to force the trans to shift into 1st, then 2nd, etc and bypass any electric shifting.

If you have an ODBII code reader the transmission has its own troubleshooting system and might have trouble codes stored.