Acura RL. Manual - part 226

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 is regulated by the regulator valve. Torque converter pressure from the regulator valve enters 
the torque converter through the lock-up shift valve and lock-up control valve, and it is discharged from the 
torque converter. The torque converter check valve prevents torque converter pressure from rising. 

The PCM controls shift solenoid valves A, B, C, and D ON and OFF, and the shift solenoid valves control shift 
solenoid pressure to the shift valves. Applying shift solenoid pressure to the shift valves moves the position of 
the shift valve, and switches the port of hydraulic pressure. 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 CPC valves A, B, and C, and the reverse CPC valve. 

When shifting between gears, the clutches are engaged by pressure from the CPC pressure mode. The PCM 
controls one of the shift solenoid valves to move the position of the shift valve. This movement switches the 
port of CPC pressure and line pressure. Line pressure is then applied to the clutch, and CPC pressure is 
released. The clutch is engaged with line pressure after shifting is completed. 

Hydraulic Pressure at the Port for use in the hydraulic circuit:  

HYDRAULIC PRESSURE PORT REFERENCE CHART 

Port

Hydraulic Pressure

Port

Hydraulic Pressure

1

Line

SC

Shift solenoid valve C

2

Line

SC'

Shift solenoid valve C

3

Line

SD

Shift solenoid valve D

3'

Line

10

1st clutch

3"

Reverse CPC or Line

15

1st-hold clutch

3A

Line

20

2nd clutch

3B

Reverse CPC

30

3rd clutch

4

Line

40

4th clutch

4'

Line

50

5th clutch

4"

Line

51

5th clutch

4A

CPC A

56

A/T clutch pressure 
control solenoid valve A

4B

CPC B

57

A/T clutch pressure 
control solenoid valve B

4C

CPC C

5R

A/T clutch pressure 
control solenoid valve B

5A

CPC A

58

A/T clutch pressure 
control solenoid valve C

5B

CPC A or Line

90

Torque converter

5C

CPC B or Line

90'

Torque converter

5D

CPC B

91

Torque converter

 

2007 Acura RL 

2005-08 TRANSMISSION Automatic Transmission - RL

  

me 

 

Friday, June 05, 2009 1:18:11 PM

Page 75 

© 2005 Mitchell Repair Information Company, LLC. 

N Position 

Line pressure (1) regulated by the regulator valve flows to shift solenoid valves. The PCM switches the shift 
solenoid valves ON and OFF. The conditions of the shift solenoid valves and positions of the shift valve are as 
follows: 



Shift solenoid valve A is OFF, and closes the port of shift solenoid valve A pressure (SA); shift valve A 
remains on the left side.  



Shift solenoid valve B is turned ON, and closes the port of shift solenoid valve B pressure (SB); shift 
valve B and shift valve E remain on the left side.  



Shift solenoid valve C is OFF, and opens the port of shift solenoid valve C pressure (SO; shift valve C 
and shift valve D move to the right side.  



Shift solenoid valve D is OFF, and closes the port of shift solenoid valve D pressure (SD).  

Line pressure (1) also flows to the modulator valve and becomes modulator pressure (6). Modulator pressure (6) 
flows to the A/T clutch pressure control solenoid valves. The manual valve covers the port leading pressure to 
the clutches, and hydraulic pressure is not applied to the clutches. 

5E

CPC C

91'

Torque converter

5F

CPC C

92

Torque converter

5G

CPC C

93

ATF cooler

5H

CPC B or Line

94

Torque converter

5J

CPC B or Line

95

Lubrication

5K

CPC A or Line

95'

Lubrication

5L

CPC A or Line

96

Torque converter

5M

Line

99

Suction

5N

CPC C

X

Drain

6

Modulator

HX

High position drain

SA

Shift solenoid valve A

AX

Air drain

SB

Shift solenoid valve B

-

-

NOTE:

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

 

2007 Acura RL 

2005-08 TRANSMISSION Automatic Transmission - RL

  

me 

 

Friday, June 05, 2009 1:18:11 PM

Page 76 

© 2005 Mitchell Repair Information Company, LLC. 

Fig. 44: Hydraulic Pressure Flow Diagram (N Position) 
Courtesy of AMERICAN HONDA MOTOR CO., INC. 

D Position: 1st gear shifting from the N position 

The shift solenoid valves remain the same as in N when shifting to D from N. The manual valve is moved to D 
position, and uncovers the port of line pressure (4) leading to CPC valves A and C. The PCM actuates A/T 
clutch pressure control solenoid valves A and C, A/T clutch pressure control solenoid valve A pressure (56) 
flows to CPC valve A, and A/T clutch pressure control solenoid valve C pressure (58) flows to CPC valve C. 
CPC valves A and C regulate line pressure (4), line pressure (4) becomes CPC C pressure (4C) at CPC valve C, 
and becomes CPC A pressure at CPC valve A. CPC C pressure (4C) becomes 1st clutch pressure (10) at shift 
valve D, and 1st clutch pressure flows to the 1st clutch. CPC A pressure (4A) becomes 2nd clutch pressure (20) 
at shift valve B via shift valves A and C. The 1st clutch and 2nd clutch engage gently by the CPC pressure. 

NOTE:

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

 

2007 Acura RL 

2005-08 TRANSMISSION Automatic Transmission - RL

  

me 

 

Friday, June 05, 2009 1:18:11 PM

Page 77 

© 2005 Mitchell Repair Information Company, LLC. 

Fig. 45: Hydraulic Pressure Flow Diagram (D Position: 1st Gear Shifting From N Position) 
Courtesy of AMERICAN HONDA MOTOR CO., INC. 

D Position: Driving in 1st gear 

The PCM turns shift solenoid valve C ON, and shift solenoid valve C covers the port of shift solenoid valve C 
pressure (SC) to shift valve C and shift valve D via shift valve E. Shift solenoid valve A remains OFF, and shift 
solenoid valve B remains ON. Shift valves C and D are moved to the left side, shift valve D switches the port of 
line pressure (4) and CPC C pressure (4C) leading to the 1st clutch, and shift valve C switches the port of CPC 
A pressure (4A) releasing 2nd clutch pressure. Line pressure (4) becomes 1st clutch pressure (10) at shift valve 
D, and flows to the 1st clutch. The 1st clutch is engaged securely by the line pressure. 

NOTE:

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

 

2007 Acura RL 

2005-08 TRANSMISSION Automatic Transmission - RL

  

me 

 

Friday, June 05, 2009 1:18:11 PM

Page 78 

© 2005 Mitchell Repair Information Company, LLC.