Acura TSX / Honda Accord CL. Manual — part 932

4th to 5th gear, from 3rd to 4th gear, and from 2nd to 3rd gear (when the throttle is closed) becomes faster than
the set speed for flat road driving to widen the 4th gear, 3rd gear, and 2nd gear driving area. This, in
combination with engine braking from the deceleration lock-up, achieves smooth driving when the vehicle is
descending. There are three descending modes with different 4th gear driving areas, 3rd gear driving areas, and
2nd gear driving areas according to the magnitude of a gradient stored in the PCM. When the vehicle is in 5th
gear or 4th gear, and you are decelerating when you are applying the brakes on a steep hill, the transmission will
downshift to lower gear. When you accelerate, the transmission will then return to a higher gear.

Fig. 39: Grade Logic Control: Descending Control Table

CLUTCH PRESSURE CONTROL

The PCM actuates the A/T clutch pressure control solenoid valves A, B, and C to control the clutch pressure.
When shifting between lower and higher gears, the clutch pressure regulated by the A/T clutch pressure control
solenoid valves A, B, and C engages and disengages the clutch smoothly.

The PCM receives input signals from the various sensors and switches, performs processing data, and outputs a
current to the A/T clutch pressure control solenoid valves A, B, and C.

2004 Acura TSX

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

Fig. 40: Clutch Pressure Control Schematic

LOCK-UP CONTROL

The shift solenoid valve E controls the hydraulic pressure to switch the lock-up shift valve and lock-up ON and
OFF.

The PCM actuates the shift solenoid valve E and the A/T clutch pressure control solenoid valve A to control the
torque converter clutch lock-up. When the shift solenoid valve E is turned ON, the condition of the lock-up
starts.

The A/T clutch pressure control solenoid valve A regulates and applies the hydraulic pressure to the lock-up
control valve to control the amount of the lock-up.

The lock-up mechanism operates in 2nd, 3rd, 4th, and 5th gears in D position, 2nd and 3rd gears in D

3

position,

and 3rd, 4th, and 5th gears in M position.

2004 Acura TSX

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

Fig. 41: Lock-up Control Schematic

PCM ELECTRICAL CONNECTIONS

2004 Acura TSX

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

Fig. 42: PCM Connector Terminal Locations

PCM INPUTS & OUTPUTS

The PCM terminal voltage and measuring conditions are shown for the connector terminals that are related to

2004 Acura TSX

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed