AT-40
[RE4F04B]
OVERALL SYSTEM
Revision: November 2006
2006 Altima
Relation between shift solenoid valves A and B and gear positions
Control of Shift Valves A and B
Pilot pressure generated by the operation of shift solenoid valves A and B is applied to the end face of shift
valves A and B.
The drawing above shows the operation of shift valve B. When the shift solenoid valve is ON, pilot pressure
applied to the end face of the shift valve overcomes spring force, moving the valve upward.
LOCK-UP CONTROL
The torque converter clutch piston in the torque converter is locked to eliminate torque converter slip to
increase power transmission efficiency. The solenoid valve is controlled by an ON-OFF duty signal sent from
the TCM. The signal is converted to an oil pressure signal which controls the lock-up piston.
Conditions for Lock-up Operation
When vehicle is driven in 4th gear position, vehicle speed and throttle opening are detected. If the detected
values fall within the lock-up zone memorized in the TCM, lock-up is performed.
Torque Converter Clutch Solenoid Valve Control
The torque converter clutch solenoid valve is controlled by the TCM.
The plunger closes the drain circuit during the OFF period, and
opens the circuit during the ON period. If the percentage of OFF-time
increases in one cycle, the pilot pressure drain time is reduced and
pilot pressure remains high.
Shift solenoid valve
Gear position
D
1
, 2
1
, 1
1
D
2
, 2
2
, 1
2
D
3
D
4
(O/D)
N-P
A
ON (Closed)
OFF (Open)
OFF (Open)
ON (Closed)
ON (Closed)
B
ON (Closed)
ON (Closed)
OFF (Open)
OFF (Open)
ON (Closed)
SAT009J
Selector lever
D position
3 position
Gear position
D
4
3
Vehicle speed sensor
More than set value
ECM (throttle opening)
Less than set opening
A/T fluid temperature sensor
More than 40
°
C (104
°
F)
SAT010J