1999 Mitsubishi Eclipse RS P0700 and P0732 DTC Codes - Gear Ratio Issue After Flywheel and Transmission Swap
I recently worked on my 1999 Mitsubishi Eclipse RS with a 4.2L 420A engine and Chrysler 41TE automatic transmission. I removed the original flywheel due to a broken torque converter (TC) connection, replaced it with a new one, and swapped in a 41TE transmission from another 1997 Eclipse. Everything appears mechanically functional now, but the car will not shift out of second gear. It's currently displaying DTC codes P0700 and P0732. P0700 is a generic code indicating a transmission control system issue, while P0732 suggests an incorrect 2nd gear ratio detection. I'm trying to understand how to diagnose and fix this without having to take it to a shop. Any insights or troubleshooting steps would be greatly appreciated. At this point, I’m considering just giving up and taking it in for professional repair — feels like I’ve hit a wall with the DIY approach. Thanks in advance for any help!
Start by inspecting the Output Speed Sensor (OSS) — this sensor is relatively inexpensive and often fails or becomes misaligned during transmission swaps. If it's faulty, replacing it can resolve both P0700 and P0732 issues. No need to buy OEM parts; a quality aftermarket sensor will work just as well and save you money.