To determine if you have a valve body/solenoid problem or a faulty ECM, determine if you have Reverse with the electrical connector disconnected from the transmission. If you DON'T have Reverse, suspect B2 control valve is stuck on or pushed to apply position by cross leaks or DSL solenoid stuck open.
If transmission engages in Reverse, suspect faulty ECM. The DSL solenoid (TCC) doesn't just come on for lockup. It also energizes in manual low and to inhibit Reverse. It's normally closed & when energized allows oil pressure to stroke B2 control valve and apply B2 clutch in manual low and block oil to the B2 clutch in Reverse.
If DSL is stuck open in Drive, B2 clutch applies in first like it does in manual low. When 1-2 shift occurs with B2 clutch applied, too many clutches are applied and the transmission binds up. If DSL is stuck open in Reverse, B2 control valve blocks oil to B2 clutch inhibiting Reverse.
The ECM (Engine Control Module) aka PCM (Powertrain Control Module) controls engine and transmission. It's not uncommon for RAV4 models between 2001-2003 to have faulty ECMs. Many times they have binding/harsh shifts and produce codes P0750, P0753, P0755, P0758 and P1760. See Toyota bulletin #TC002-06 dated March 3, 2006.
NOTE: This is an adaptive learn transmission. Learned adapts must be reset after overhaul or valve body replacement to avoid damage. It resets all ECM learned adapts, not just transmission adapts. A Toyota factory scanner can reset ECM adapts. After resetting adapts, bring transaxle to operating temp and drive vehicle at light steady throttle through all shifts. Repeat until shifts feel normal. You may find that resetting shift adapts will correct binding on shifts, therefore, perform reset before replacing an ECM.
|3rd, TCC On
|4th, TCC On
Direct clutch sealing rings wear into ring grooves of cover and direct drum can be ring grooved. Clearance between sealing ring and ring land is .003"-.005". Direct drums with damage where sealing rings ride should be replaced. DON'T try to salvage drum by sanding. Another cause of pressure loss is missing/incorrectly placed washer seal between case and rear cover.
||Dia.||No. of Coils
I work on transmissions for a living.
I work on other people’s vehicles for a living.
I am interested in enhancing my vehicle’s performance.
I work on my own vehicle(s) only.
None of the above categories describe me.
While Sonnax makes every effort to ensure the accuracy of technical articles at time of publication, we assume no liability for inaccuracies or for information which may become outdated or obsolete over time.