Acura TSX / Honda Accord CL. Manual - part 931

The PCM switches the shift solenoid valves and the A/T clutch pressure control solenoid valves to control 
shifting transmission gears and lock-up torque converter clutch. 

Fig. 34: Electronic Control System Schematic 

Electronic Controls Location 

 

2004 Acura TSX 

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

  

 

Fig. 35: Locating Electronic Controls 

SHIFT CONTROL 

The PCM instantly determines which gear should be selected by various signals sent from sensors and switches, 
and it actuates the shift solenoid valves A, B, C, D, and E to control shifting. 

Also, a grade logic control system has been adopted to control shifting in D and D

3

 positions. The PCM 

compares actual driving conditions with memorized driving conditions, based on the input from the throttle 
position sensor, the engine coolant temperature sensor, the barometric pressure sensor, the brake pedal position 

 

2004 Acura TSX 

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

  

 

switch signal, and the shift lever position signal, to control shifting while the vehicle is ascending or descending 
a slope. 

Fig. 36: Shift Control Schematic 

The PCM turns the shift solenoid valves A, B, C, D, and E ON and OFF to control shifting transmission gear. 
The combination of driving signals to shift solenoid valves A, B, C, D, and E are shown in table below.

 

2004 Acura TSX 

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

  

 

Fig. 37: Transmission Gear/Shift Solenoid Valve Table 

GRADE LOGIC CONTROL: ASCENDING CONTROL 

When the PCM determines that the vehicle is climbing a hill in D and D

3

 positions, the system extends the 

engagement area of 2nd, 3rd, and 4th gears to prevent the transmission from frequently shifting between 2nd 
and 3rd gears, between 3rd and 4th gears, and between 4th and 5th gears, so the vehicle can run smooth and 
have more power when needed. 

Shift schedules stored in the PCM between 2nd and 3rd gears, between 3rd and 4th gears, and between 4th and 
5th gears, enable it to automatically select the most suitable gear according to the magnitude of a gradient. 

Fig. 38: Grade Logic Control: Ascending Control Table 

GRADE LOGIC CONTROL: DESCENDING CONTROL 

When the PCM determines that the vehicle is going down a hill in D and D

3

 positions, the shift-up speed from 

 

2004 Acura TSX 

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed