The vehicle exhibits a harsh TCC apply accompanied by an illuminated malfunctioning indicator light (MIL). Upon code retrieval, P2757 is obtained which is a torque converter clutch pressure control solenoid (SLU) performance fault code.
Toyota’s 6 speed U660E utilizes a flex lock-up control converter clutch apply strategy which under specific driving conditions will allow a partial apply of the converter clutch as early as 2nd gear all the way to 6th gear. This flex control is accomplished through the use of a uniquely designed 3-port passage to the converter (Figure 1), an SL and an SLU solenoid (Figure 2), a lock-up Relay Valve and a Lock-Up Control Valve (Figure 3).
TCC off, flex and full apply hydraulics can be seen in figures 4, 5 and 6.
When the TCM request the apply of the clutch, it monitors the percentage of apply by comparing engine rpm to the turbine rpm. Should the desired apply exceed the minimum or maximum range of the command given, P2757 sets causing the MIL to illuminate.
The two most common possibilities that can compromise the apply performance of the converter clutch causing P2757 to set is a mechanically failed SLU solenoid and/or lock-up control valve bore wear as the valve is steel and the housing is aluminum. When the SL solenoid has a performance problem it usually produces a P0741 code.
Inspect the performance of the SLU solenoid and replace as necessary.
Inspect the lock-up control valve bore for wear, repair or replace as necessary.
Special note 1: The SLU and SLT solenoids are next to each other in the valve body. These two solenoids are dimensionally the same and can be inserted into the valve body in the wrong location. This will cause both line pressure and TCC apply issues as these two solenoids function differently. The SLT solenoid can be easily identified by 5 slotted passages to the valve in the snout of the solenoid while the SLU has 4 (Figure 7).
Use Figure 8 for their proper location.
Special note 2: The SL, SLU and SLT solenoids are supplied with pressure from the Solenoid Modulating Valve (Figure 9). This too is a steel valve in an aluminum housing and is prone to wearing the bore. This will affect both line pressure control and TCC control making this an important bore to inspect at all times.
Special note 3: Toyota Bulletin T-SB-0061-08 dated May 13, 2008, stipulates that 2007-08 Camry and 2008 Avalon may experience a TCC Shudder on light acceleration between speeds of 26 mph (4th) and 36 mph (5th) and/or 44 mph (6th).
Production changes were made to the torque converter to improve this condition and is covered under the 60-month/60,000-mile warranty, whichever comes first from the vehicle’s in-service date. This TSB applies to vehicles produced BEFORE the production change effective VINs shown below.
From TMMK plant:
4T1BK36B#8U299716
4T1BK46B#9U076421
4T1BK46B#9U579648
From Tsutsumi plant:
JTNBK46K#83035861
May 2018 Issue
Volume 35, No. 5
- Toyota U660-E: Harsh TCC apply
