Acura TSX / Honda Accord CL. Manual — part 938

Fig. 68: D Position: Driving In 5th Gear Hydraulic Flow

R Position: Shifting to R position from P or N position

When shifting to the R position, the PCM turns shift solenoid valves B and E ON, and A, C, and D OFF. Shift
solenoid valve B pressure (SB) is applied to the right side of the shift valve B, and the shift valve B is moved to
the left side. Shift solenoid valve E pressure (SE) is applied to the left side of shift valve E, and shift valve E is
moved to the right side. Line pressure (1) changes to (3) at the manual valve, and flows to the servo valve via
the shift valve E. The servo valve is moved to reverse range position. Movement of the shift valves B and E,
and servo valve creates 4th clutch line pressure between the 4th clutch and the A/T clutch pressure control
solenoid valve A. The 4th clutch pressure (40) is applied to the 4th clutch, and the 4th clutch is engaged gently.

NOTE:

When used, "left" or "right" indicates direction on the hydraulic circuit.

2004 Acura TSX

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

Fig. 69: R Position: Shifting To R Position From P Or N Position Hydraulic Flow

R Position: Driving in reverse gear

After starting off in reverse gear, the PCM turns shift solenoid valves A ON, and keeps B and E ON, and C and
D OFF. Shift solenoid valve A port (SA) is applied to the right side of shift valve A to cover A/T clutch
pressure control solenoid valve A pressure, and to uncover the port leading to the 4th clutch, creating full line
pressure. The 4th clutch is engaged securely with line pressure.

Reverse Inhibitor Control

While the vehicle is moving forward, the PCM keeps shift solenoid valve E OFF. The shift valve E covers the
port of line pressure (3') leading to the servo valve reverse position. The servo valve cannot be shifted to reverse
position, and hydraulic pressure is not applied to 4th clutch from the servo valve for reverse; as a result, power
is not transmitted to the reverse direction.

NOTE:

When used, "left" or "right" indicates direction on the hydraulic circuit.

2004 Acura TSX

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

Fig. 70: Reverse Inhibitor Control Hydraulic Flow

P Position

Shift solenoid valves B and E are turned ON, and A, C, and D turned OFF by the PCM. Line pressure (1) flows
to the shift solenoid valves and the A/T clutch pressure control solenoid valve A. Line pressure (3) changes to
(3') at the shift valve E, and flows to the servo valve. The servo valve is moved to reverse/park position.
Hydraulic pressure is not applied to the clutches.

2004 Acura TSX

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

Fig. 71: P Position Hydraulic Flow

LOCK-UP SYSTEM

The lock-up mechanism of the torque converter clutch operates in D position (2nd, 3rd, 4th, and 5th), in D

3

position (2nd and 3rd), and M (sequential sportshift mode) position (3rd, 4th, and 5th). The pressurized fluid is
drained from the back of the torque converter through a fluid passage, causing the torque converter clutch piston
to be held against the torque converter cover. As this takes place, the mainshaft rotates at the same speed as the
engine crankshaft.

Together with the hydraulic control, the PCM optimizes the timing and volume of the lock-up mechanism.
When shift solenoid valve E is turned on by the PCM, shift solenoid valve E pressure switches the lock-up shift
valve lock-up on and off. The A/T clutch pressure control solenoid valve A and the lock-up control valve
control the amount of the lock-up conditions.

Torque Converter Clutch Lock-up ON (Engaging Torque Converter Clutch)

Fluid in the chamber between the torque converter cover and the torque converter clutch piston is drained off,
and fluid entering from the chamber between the pump and stator exerts pressure through the torque converter
clutch piston against the torque converter cover. The torque converter clutch piston engages with the torque
converter cover; the torque converter clutch lock-up is ON, and the mainshaft rotates at the same speed as the

2004 Acura TSX

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed