Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2006 Nissan-Datsun Sentra SE-RFACTORY OEM SERVICE PROCEDURE
Function Of Control Valves
CONTROL VALVES FUNCTIONS
| Valve name | Function |
|---|---|
| Pressure regulator valve, plug and sleeve plug | Regulates oil discharged from the oil pump to provide optimum line pressure for all driving conditions. |
| Pressure modifier valve and sleeve | Used as a signal supplementary valve to the pressure regulator valve. Regulates pressure-modifier pressure (signal pressure) which controls optimum line pressure for all driving conditions. |
| Pilot valve | Regulates line pressure to maintain a constant pilot pressure level which controls lock-up mechanism, overrun clutch, shift timing. |
| Accumulator control valve | Regulates accumulator back-pressure to pressure suited to driving conditions. |
| Manual valve | Directs line pressure to oil circuits corresponding to select positions. Hydraulic pressure drains when the shift lever is in Neutral. |
| Shift valve A | Simultaneously switches three oil circuits using output pressure of shift solenoid valve A to meet driving conditions (vehicle speed, throttle opening, etc.). Provides automatic downshifting and up-shifting (1st --> 2nd --> 3rd --> 4th gears/4th --> 3rd --> 2nd --> 1st gears) in combination with shift valve B. |
| Shift valve B | Simultaneously switches two oil circuits using output pressure of shift solenoid valve B in relation to driving conditions (vehicle speed, throttle opening, etc.). Provides automatic downshifting and up-shifting (1st --> 2nd --> 3rd --> 4th gears/4th --> 3rd --> 2nd --> 1st gears) in combination with shift valve A. |
| Overrun clutch control valve | Switches hydraulic circuits to prevent engagement of the overrun clutch simultaneously with application of the brake band in D4. (Interlocking occurs if the overrun clutch engages during D4.) |
| "1" reducing valve | Reduces low & reverse brake pressure to dampen engine-brake shock when down-shifting from the 1 position 12 to 11. |
| Overrun clutch reducing valve | Reduces oil pressure directed to the overrun clutch and prevents engine-brake shock. In 1 and 2 positions, line pressure acts on the overrun clutch reducing valve to increase the pressure-regulating point, with resultant engine brake capability. |
| Torque converter relief valve | Prevents an excessive rise in torque converter pressure. |
| Torque converter clutch control valve, plug and sleeve | Activates or inactivates the lock-up function. Also provides smooth lock-up through transient application and release of the lock-up system. |
| 1-2 accumulator valve and piston | Dampens the shock encountered when 2nd gear band servo contracts, and provides smooth shifting. |
| 3-2 timing valve | Switches the pace that oil pressure is released depending on vehicle speed; maximizes the high clutch release timing, and allows for soft down shifting. |
| Shuttle valve | Determines if the overrun clutch solenoid valve should control the 3-2 timing valve or the overrun clutch control valve and switches between the two. |
| Cooler check valve | At low speeds and with a small load when little heat is generated, saves the volume of cooler flow, and stores the oil pressure for lock up. |
Factory Service Tools
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.
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