A/T FLUID AT-15
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A/T Fluid Cooler CleaningACS004Q5
Whenever an automatic transmission is replaced, the A/T fluid cooler mounted in the radiator must be
inspected and cleaned.
Metal debris and friction material, if present, can become trapped in the A/T fluid cooler. This debris can con-
taminate the newly serviced A/T or, in severe cases, can block or restrict the flow of ATF. In either case, mal-
function of the newly serviced A/T may result.
Debris, if present, may build up as ATF enters the cooler inlet. It will be necessary to back flush the cooler
through the cooler outlet in order to flush out any built up debris.
A/T FLUID COOLER CLEANING PROCEDURE
1. Position an oil pan under the automatic transmission's inlet and outlet cooler hoses.
2. Identify the inlet and outlet A/T fluid cooler hoses.
3. Disconnect the A/T fluid cooler inlet and outlet rubber hoses from the steel cooler tubes or bypass valve.
NOTE:
Replace the cooler hoses if rubber material from the hose
remains on the tube fitting.
4. Allow any ATF that remains in the cooler hoses to drain into the oil pan.
5. Insert the extension adapter hose of a can of Transmission Cooler Cleaner (Nissan P/N 999MP-AM006) into the cooler out-
let hose.
CAUTION:
Wear safety glasses and rubber gloves when spraying
the Transmission Cooler Cleaner.
Spray cooler cleaner only with adequate ventilation.
Avoid contact with eyes and skin.
Do not breath vapors or spray mist.
6. Hold the hose and can as high as possible and spray Transmis- sion Cooler Cleaner in a continuous stream into the cooler outlet
hose until ATF flows out of the cooler inlet hose for 5 seconds.
7. Insert the tip of an air gun into the end of the cooler outlet hose.
8. Wrap a shop rag around the air gun tip and of the cooler outlet hose.
9. Blow compressed air regulated to 5 to 9 kg/cm
2 (70 to 130 psi)
through the cooler outlet hose for 10 seconds to force out any
remaining ATF.
10. Repeat steps 5 through 9 three additional times.
11. Position an oil pan under the banjo bolts that connect the A/T fluid cooler steel lines to the transmission.
12. Remove the banjo bolts.
13. Flush each steel line from the cooler side back toward the trans- mission by spraying Transmission Cooler Cleaner in a continuous stream for 5 seconds.
14. Blow compressed air regulated to 5 to 9 kg/cm
2 (70 to 130 psi) through each steel line from the cooler
side back toward the transmission for 10 seconds to force out any remaining ATF.
15. Ensure all debris is removed from the steel cooler lines.
16. Ensure all debris is removed from the banjo bolts and fittings.
17. Perform AT- 1 6 , "
A/T FLUID COOLER DIAGNOSIS PROCEDURE" .
SCIA3830E
SCIA3831E
SCIA3832E
A/T CONTROL SYSTEM AT-31
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TCM FunctionACS002LF
The function of the TCM is to:
Receive input signals sent from various switches and sensors.
Determine required line pressure, shifting point, lock-up operation, and engine brake operation.
Send required output signals to the respective solenoids.
CONTROL SYSTEM OUTLINE
The automatic transmission senses vehicle operating conditions through various sensors or signals. It always
controls the optimum shift position and reduces shifting and lock-up shocks.
CONTROL SYSTEM DIAGRAM
SENSORS (or SIGNALS)
TCM
ACTUATORS
PNP switch
Accelerator pedal position signal
Closed throttle position signal
Wide open throttle position signal
Engine speed signal
A/T fluid temperature sensor
Revolution sensor
Vehicle speed signal
Manual mode switch signal
Stop lamp switch signal
Turbine revolution sensor
ATF pressure switch Shift control
Line pressure control
Lock-up control
Engine brake control
Timing control
Fail-safe control
Self-diagnosis
CONSULT-II communication line
Duet-EA control
CAN system Input clutch solenoid valve
Direct clutch solenoid valve
Front brake solenoid valve
High and low reverse clutch
solenoid valve
Low coast brake solenoid valve
Torque converter clutch solenoid
valve
Line pressure solenoid valve
A/T CHECK indicator lamp
Sta r te r re l a y
Back-up lamp relay
SCIA5325E
AT-32
A/T CONTROL SYSTEM
Revision: 2005 July 2005 FX
CAN CommunicationACS004PB
SYSTEM DESCRIPTION
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.For details, refer to LAN-30,
"CAN Communication Unit"
Input/Output Signal of TCMACS002LH
*1: Spare for vehicle speed sensor·A/T (revolution sensor)
*2: Spare for accelerator pedal position signal
*3: If these input and output signals are different, the TCM triggers the fail-safe function.
*4: Used as a condition for starting self-diagnostics; if self-diagnostics are not started, it is judged that there is some kin d of error.
*5: Input by CAN communications
*6: Output by CAN communications Control item
Line
pressure control Vehicle
speed
control Shift
control Lock-up
control Engine
brake
control Fail-safe
function (*3) Self-diag-
nostics
function
Input Accelerator pedal position signal
(*5)XXXXXXX
Vehicle speed sensor A/T
(revolution sensor) XXXXXXX
Vehicle speed sensor MTR
(*1) (*5)X
Closed throttle position signal
(*5)X (*2) X X X X (*4)
Wide open throttle position signal
(*5)XX (*4)
Turbine revolution sensor 1 X X X X X
Turbine revolution sensor 2
(for 4th speed only) XXXXX
Engine speed signals
(*5)XXXXXXX
Stop lamp switch signal
(*5)XXX X (*4)
A/T fluid temperature sensors 1, 2 X X X X X X
ASCD or
ICC Operation signal
(*5)XXX
Overdrive cancel
signal
(*5)X
Out-
put Direct clutch solenoid (ATF pres-
sure switch 5) XX XX
Input clutch solenoid (ATF pressure
switch 3) XX XX
High and low reverse clutch sole-
noid (ATF pressure switch 6) XX XX
Front brake solenoid (ATF pressure
switch 1) XX XX
Low coast brake solenoid (ATF
pressure switch 2) XX XXX
Line pressure solenoid XXXXXXX
TCC solenoid X X X
Self-diagnostics table
(*6)X
Starter relay XX
A/T CONTROL SYSTEM AT-35
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SHIFT CHANGE
The clutch is controlled with the optimum timing and oil pressure by the engine speed, engine torque informa-
tion, etc.
Shift Change System Diagram
*1: Full phase real-time feedback control monitors movement of gear ratio at gear change, and controls oil
pressure at real-time to achieve the best gear ratio.
Lock-up ControlACS002LK
The torque converter clutch piston in the torque converter is engaged to eliminate torque converter slip to
increase power transmission efficiency.
The torque converter clutch control valve operation is controlled by the torque converter clutch solenoid valve,
which is controlled by a signal from TCM, and the torque converter clutch control valve engages or releases
the torque converter clutch piston.
Lock-up Operation Condition Table
TORQUE CONVERTER CLUTCH CONTROL VALVE CONTROL
Lock-up Control System Diagram
PCIA0013E
selector lever D position M5 position M4 position
Gear position 5 4 5 4
Lock-up ×– ××
Slip lock-up ××––
PCIA0014E
AT-36
A/T CONTROL SYSTEM
Revision: 2005 July 2005 FX
Lock-up Released
In the lock-up released state, the torque converter clutch control valve is set into the unlocked state by the
torque converter clutch solenoid and the lock-up apply pressure is drained.
In this way, the torque converter clutch piston is not coupled.
Lock-up Applied
In the lock-up applied state, the torque converter clutch control valve is set into the locked state by the
torque converter clutch solenoid and lock-up apply pressure is generated.
In this way, the torque converter clutch piston is pressed and coupled.
SMOOTH LOCK-UP CONTROL
When shifting from the lock-up released state to the lock-up applied state, the current output to the torque con-
verter clutch solenoid is controlled with the TCM. In this way, when shifting to the lock-up applied state, the
torque converter clutch is temporarily set to the half-clutched state to reduce the shock.
Half-clutched State
The current output from the TCM to the torque converter clutch solenoid is varied to gradually increase
the torque converter clutch solenoid pressure.
In this way, the lock-up apply pressure gradually rises and while the torque converter clutch piston is put
into half-clutched status, the torque converter clutch piston operating pressure is increased and the cou-
pling is completed smoothly.
Slip Lock-up Control
In the slip region, the torque converter clutch solenoid current is controlled with the TCM to put it into the
half-clutched state. This absorbs the engine torque fluctuation and lock-up operates from low speed.
This raises the fuel efficiency for 4th and 5th gears at both low speed and when the accelerator has a low
degree of opening.
Engine Brake ControlACS002LL
The forward one-way clutch transmits the drive force from the engine to the rear wheels. But the reverse
drive from the rear wheels is not transmitted to the engine because the one-way clutch is idling.
Therefore, the low coast brake solenoid is operated to prevent the forward one-way clutch from idling and
the engine brake is operated in the same manner as conventionally.
The operation of the low coast brake solenoid switches the low coast brake switching valve and controls
the coupling and releasing of the low coast brake.
The low coast brake reducing valve controls the low coast brake coupling force.
SCIA1520E
A/T CONTROL SYSTEM AT-37
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Control ValveACS002LM
FUNCTION OF CONTROL VALVE
Name Function
Torque converter regulator valve In order to prevent the pressure supplied to the torque converter from being excessive,
the line pressure is adjusted to the optimum pressure (torque converter operating pres-
sure).
Pressure regulator valve
Pressure regulator plug
Pressure regulator sleeve Adjusts the oil discharged from the oil pump to the optimum pressure (line pressure) for
the driving state.
Front brake control valve When the front brake is coupled, adjusts the line pressure to the optimum pressure
(front brake pressure) and supplies it to the front brake. (In 1st, 2nd, 3rd, and 5th gears,
adjusts the clutch pressure.)
Accumulator control valve Adjusts the pressure (accumulator control pressure) acting on the accumulator piston
and low coast reducing valve to the pressure appropriate to the driving state.
Pilot valve A Adjusts the line pressure and produces the constant pressure (pilot pressure) required
for line pressure control, shift change control, and lock-up control.
Pilot valve B Adjusts the line pressure and produces the constant pressure (pilot pressure) required
for shift change control.
Low coast brake switching valve During engine braking, supplies the line pressure to the low coast brake reducing valve.
Low coast brake reducing valve When the low coast brake is coupled, adjusts the line pressure to the optimum pressure
(low coast brake pressure) and supplies it to the low coast brake.
N-R accumulator Produces the stabilizing pressure for when N-R is selected.
Direct clutch piston switching valve Operates in 4th gear and switches the direct clutch coupling capacity.
High and low reverse clutch control valve When the high and low reverse clutch is coupled, adjusts the line pressure to the opti-
mum pressure (high and low reverse clutch pressure) and supplies it to the high and low
reverse clutch. (In 1st, 3rd, 4th and 5th gears, adjusts the clutch pressure.)
Input clutch control valve When the input clutch is coupled, adjusts the line pressure to the optimum pressure
(input clutch pressure) and supplies it to the input clutch. (In 4th and 5th gears, adjusts
the clutch pressure.)
Direct clutch control valve When the direct clutch is coupled, adjusts the line pressure to the optimum pressure
(direct clutch pressure) and supplies it to the direct clutch. (In 2nd, 3rd, and 4th gears,
adjusts the clutch pressure.)
TCC control valve
TCC control plug
TCC control sleeve Switches the lock-up to operating or released. Also, by performing the lock-up operation
transiently, lock-up smoothly.
Torque converter lubrication valve Operates during lock-up to switch the torque converter, cooling, and lubrication system
oil passage.
Cool bypass valve Allows excess oil to bypass cooler circuit without being fed into it.
Line pressure relief valve Discharges excess oil from line pressure circuit.
N-D accumulator Produces the stabilizing pressure for when N-D is selected.
Manual valve Sends line pressure to each circuit according to the select position. The circuits to which
the line pressure is not sent drain.
AT-44
TROUBLE DIAGNOSIS
Revision: 2005 July 2005 FX
A/T Interlock
If there is an A/T interlock judgment malfunction, the transmission is fixed in 2nd gear to make driving pos-
sible.
NOTE:
When the vehicle is driven fixed in 2nd gear, a turbine revolution sensor malfunction is displayed,
but this is not a turbine revolution sensor malfunction.
When the coupling pattern below is detected, the fail-safe action corresponding to the pattern is per-
formed.
A/T INTERLOCK COUPLING PATTERN TABLE
: NG X: OK
A/T 1st Engine Braking
When there is an A/T first gear engine brake judgment malfunction, the low coast brake solenoid is
switched OFF to avoid the engine brake operation.
Line Pressure Solenoid
The solenoid is switched OFF and the line pressure is set to the maximum hydraulic pressure to make
driving possible.
Torque Converter Clutch Solenoid
The solenoid is switched OFF to release the lock-up.
Low Coast Brake Solenoid
When a (electrical or functional) malfunction occurs, in order to make driving possible, if the solenoid is
ON, the transmission is held in 2nd gear; if the solenoid is OFF, the transmission is held in 4th gear.
(Engine brake is not applied in 1st and 2nd gear.)
Input Clutch Solenoid
If a (electrical or functional) malfunction occurs with the solenoid either ON or OFF, the transmission is
held in 4th gear to make driving possible.
Direct Clutch Solenoid
If a (electrical or functional) malfunction occurs with the solenoid either ON or OFF, the transmission is
held in 4th gear to make driving possible.
Front Brake Solenoid
If a (electrical or functional) malfunction occurs with the solenoid ON, in order to make driving possible,
the A/T is held in 5th gear; if the solenoid is OFF, 4th gear.
High and Low Reverse Clutch Solenoid
If a (electrical or functional) malfunction occurs with the solenoid either ON or OFF, the transmission is
held in 4th gear to make driving possible.
Turbine Revolution Sensor 1 or 2
The control is the same as if there were no turbine revolution sensors, 5th gear and manual mode are pro-
hibited.
Gear position ATF pressure switch output
Fail-safe function Clutch pressure output pattern after fail-safe func-
tion
SW3 (I/C) SW6
(HLR/ C) SW5
(D/C) SW1
(FR/B) SW2
(LC/B) I/C HLR/C D/C FR/B LC/B L/U
A/T inter-
lock cou-
pling pattern 3rd – X X –
Held in
2nd gear OFF OFF ON OFF OFF OFF
4th – X X – Held in
2nd gear OFF OFF ON OFF OFF OFF
5th X X – X Held in
2nd gear OFF OFF ON OFF OFF OFF
TROUBLE DIAGNOSIS AT-45
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How to Perform Trouble Diagnosis for Quick and Accurate RepairACS002LU
INTRODUCTION
The TCM receives a signal from the vehicle speed sensor, accelerator pedal position sensor (throttle position
sensor) or PNP switch and provides shift control or lock-up control via A/T solenoid valves.
The TCM also communicates with the ECM by means of a signal
sent from sensing elements used with the OBD-related parts of the
A/T system for malfunction-diagnostic purposes. The TCM is capa-
ble of diagnosing malfunctioning parts while the ECM can store mal-
functions in its memory.
Input and output signals must always be correct and stable in the
operation of the A/T system. The A/T system must be in good oper-
ating condition and be free of valve seizure, solenoid valve malfunc-
tion, etc.
It is much more difficult to diagnose a error that occurs intermittently
rather than continuously. Most intermittent errors are caused by poor
electric connections or improper wiring. In this case, careful check-
ing of suspected circuits may help prevent the replacement of good
parts.
A visual check only may not find the cause of the errors. A road test
with CONSULT-II (or GST) or a circuit tester connected should be
performed. Follow the AT- 4 6 , "
WORK FLOW" .
Before undertaking actual checks, take a few minutes to talk with a
customer who approaches with a driveability complaint. The cus-
tomer can supply good information about such errors, especially
intermittent ones. Find out what symptoms are present and under
what conditions they occur. A “DIAGNOSTIC WORKSHEET” as
shown on the example (Refer to AT- 4 7
) should be used.
Start your diagnosis by looking for “conventional” errors first. This will
help troubleshoot driveability errors on an electronically controlled
engine vehicle.
Also check related Service bulletins.
SAT631IB
SAT632I
SEF234G