No 1-2 &/Or 2-3 Upshift
WARNING: This page is about a different car, the 2003 Toyota RAV4, 2002 Toyota RAV4, 2002 Toyota Highlander, 2001 Toyota RAV4, and 2001 Toyota Highlander. However, it is still accessible from the selected car via links, so may be relevant.
Check Throttle Position (TP) sensor circuit, SL1 and SL2 shift solenoid circuit, Vehicle Speed Sensor (VSS) circuit, ECM, 1-2 shift valve, 2-3 shift valve, 2nd brake, direct clutch and No. 1 one-way clutch.