Acura TSX / Honda Accord CL. Manual — part 935

Accumulator

The accumulators are located in the regulator valve body and the servo body. The regulator valve body contains
the 1st and 3rd accumulators, and the servo body contains the 2nd, 4th, and 5th accumulators.

Fig. 56: Identifying Accumulators

HYDRAULIC FLOW

Distribution of Hydraulic Pressure

As the engine turns, the ATF pump starts to operate. Automatic transmission fluid (ATF) is drawn through the
ATF strainer (filter) and discharged into the hydraulic circuit. Then, ATF flowing from the ATF pump becomes
line pressure that's regulated by the regulator valve. Torque converter pressure from the regulator valve enters
the torque converter through the lock-up shift valve, and it is discharged from the torque converter. The torque
converter check valve prevents torque converter pressure from rising.

The PCM controls the shift solenoid valves ON and OFF. The shift solenoid valve intercepts line pressure from
the ATF pump via the manual valve when the shift solenoid valve is OFF. When the shift solenoid valve is
turned ON, line pressure changes to shift solenoid valve pressure at the shift solenoid valve, then the solenoid
valve pressure flows to the shift valve. Applying shift solenoid pressure to the shift valves moves the position of
the shift valve, and switches the port of the hydraulic circuit. The PCM also controls A/T clutch pressure
control solenoid valves A, B, and C. The A/T clutch pressure control solenoid valves regulate hydraulic
pressure, and apply the pressure to the clutches to engage smoothly. The clutches receive optimum clutch
pressure which is regulated by the A/T clutch pressure control solenoid valves for comfortable driving and
shifting under all conditions.

2004 Acura TSX

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

Fig. 57: Distribution Of Hydraulic Pressure At The Ports

N Position

The PCM controls the shift solenoid valves. The conditions of the shift solenoid valves and positions of the shift
valves are as follows:

z

Shift solenoid valve A: OFF Shift valve A stays on right side

z

Shift solenoid valve B: ON Shift valve B moves to left side

z

Shift solenoid valve C: ON Shift valve C moves to left side

z

Shift solenoid valve D: OFF Shift valve D stays on left side

z

Shift solenoid valve E: OFF Shift valve E stays on left side

Line pressure (1) flows to the shift solenoid valves and the A/T clutch pressure control solenoid valve A, and
changes to A/T clutch pressure control solenoid valve A pressure (55) at the A/T clutch pressure control
solenoid valve A. A/T clutch pressure control solenoid valve A pressure (55) becomes line pressure (1B) at the
shift valve A, and stops at the manual valve. Under this condition, hydraulic pressure is not applied to the
clutches.

2004 Acura TSX

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

Fig. 58: N Position Hydraulic Flow

D Position: 1st gear shifting from N position

Shift solenoid valves remain the same as in the N position, when shifting to the D position from N . The manual
valve is moved to the D position, and switches the port of line pressure (4) leading to the A/T clutch pressure
control solenoid valve C. Hydraulic pressure to the 1st clutch from the A/T clutch pressure control solenoid
valve A is available as shift solenoid valve A is OFF, B and C stay ON. A/T clutch pressure control solenoid
valve A pressure (55) changes to 1st clutch pressure (10) at the shift valve B, and flows to the 1st clutch. The
1st clutch is engaged gently when shifting to the D position from N .

NOTE:

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

NOTE:

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

2004 Acura TSX

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

Fig. 59: D Position: 1st Gear Shifting From N Position Hydraulic Flow

D Position: Driving in 1st gear

The PCM turns shift solenoid valves A ON, and keeps B and C ON, and D and E OFF. Shift solenoid valve A
pressure (SA) is applied to the right side of shift valve A. Shift valve A is moved to the left side to uncover the
line pressure port leading to the 1st clutch, and to cover A/T clutch pressure control solenoid valve pressure
port.

Fluid flows to the 1st clutch by way of:

Line pressure (1) --> Shift valve D--Line pressure (1A) --> Shift valve A--Line pressure (1B) Manual valve--
Line pressure (5A) --> Shift valve C--Line pressure (5B) --> Shift valve B--1st clutch pressure (10) --> 1st
clutch

The 1st clutch pressure (10) is applied to the 1st clutch, and the 1st clutch, is engaged securely.

NOTE:

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

2004 Acura TSX

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed