A/T CONTROL SYSTEM
TM-339
< FUNCTION DIAGNOSIS >[TYPE 2 (4AT: RE4F03B)]
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P*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-diagnosis are not started, it is judged that there is some kind of error.
*5: Input by CAN communications.
*6: Output by CAN communications.
Line Pressure ControlINFOID:0000000001714314
TCM has various line pressure control characteristics to match the driving conditions.
An ON-OFF duty signal is sent to the line pressure solenoid valve based on TCM characteristics.
Hydraulic pressure on the clutch and brake is electronically controlled through the line pressure solenoid
valve to accommodate engine torque. This results in smooth shift operation.
NORMAL CONTROL
The characteristic of the line pressure to the throttle opening is set
for suitable clutch operation.
BACK-UP CONTROL (ENGINE BRAKE)
If the selector lever is shifted to “2” position while driving in D4 or D3,
great driving force is applied to the clutch inside the transaxle. Clutch
operating pressure (line pressure) must be increased to deal with
this driving force.
DURING SHIFT CHANGE
Out-
putShift solenoid valve A/B X (*3) X X
Line pressure solenoid X (*3) X X
Torque converter clutch solenoid
valveX(*3) XX
Overrun clutch solenoid valve X X (*3) X X
OD OFF indicator lamp
(*6)XX Control itemLine
pressure
controlVeh icl e
speed
controlShift
controlLock-up
controlEngine
brake
controlFail-safe
functionSelf-diag-
nostics
function
SAT003J
SAT004J
TM-340
< FUNCTION DIAGNOSIS >[TYPE 2 (4AT: RE4F03B)]
A/T CONTROL SYSTEM
The line pressure is temporarily reduced corresponding to a change
in engine torque when shifting gears (that is, when the shift solenoid
valve is switched for clutch operation) to reduce shifting shock.
AT LOW FLUID TEMPERATURE
A/T fluid viscosity and frictional characteristics of the clutch facing change with A/T fluid temperature. Clutch
engaging or band-contacting pressure is compensated for, according to A/T fluid temperature, to stabilize
shifting quality.
The line pressure is reduced below 60°C (140°F) to prevent shift-
ing shock due to high viscosity of A/T fluid when temperature is
low.
Line pressure is increased to a maximum irrespective of the throt-
tle opening when A/T fluid temperature drops to −10°C (14°F). This
pressure rise is adopted to prevent a delay in clutch and brake
operation due to extreme drop of A/T fluid viscosity at low temper-
ature.
Shift ControlINFOID:0000000001714315
The shift is regulated entirely by electronic control to accommodate vehicle speed and varying engine opera-
tions. This is accomplished by electrical signals transmitted by the revolution sensor and the ECM (accelerator
pedal position sensor). This results in improved acceleration performance and fuel economy.
CONTROL OF SHIFT SOLENOID VALVES A AND B
The TCM activates shift solenoid valves A and B according to sig-
nals from the accelerator pedal position sensor and revolution sen-
sor to select the optimum gear position on the basis of the shift
schedule memorized in the TCM.
The shift solenoid valve performs simple ON-OFF operation. When
set to “ON”, the drain circuit closes and pilot pressure is applied to
the shift valve.
RELATION BETWEEN SHIFT SOLENOID VALVES A AND B AND GEAR POSITIONS
SCIA4828E
SCIA4829E
SCIA4830E
SAT008J
TM-342
< FUNCTION DIAGNOSIS >[TYPE 2 (4AT: RE4F03B)]
A/T CONTROL SYSTEM
Lock-up Control System Diagram
Lock-up Released
In the lock-up released state, the torque converter clutch control valve is set into the unlocked state by drain-
ing the torque converter clutch piston applying pressure and the torque converter clutch piston release pres-
sure is generated.
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 generating
the torque converter clutch piston applying pressure and the torque converter clutch piston release pressure is
drained.
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 steadily increase the
torque converter clutch solenoid pressure.
In this way, the lock-up applying pressure gradually rises and while the torque converter clutch piston is put
into half-clutched status, the torque converter clutch piston applying pressure is increased and the coupling is
completed smoothly.
Engine Brake Control (Overrun Clutch Control)INFOID:0000000001714317
Forward one-way clutch is used to reduce shifting shocks in downshifting operations. This clutch transmits
engine torque to the wheels. However, drive force from the wheels is not transmitted to the engine because
the one-way clutch rotates idle. This means the engine brake is not effective.
The overrun clutch operates when the engine brake is needed.
SCIA5623E
A/T CONTROL SYSTEM
TM-343
< FUNCTION DIAGNOSIS >[TYPE 2 (4AT: RE4F03B)]
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OVERRUN CLUTCH OPERATING CONDITIONS
OVERRUN CLUTCH SOLENOID VALVE CONTROL
The overrun clutch solenoid valve is operated by an ON-OFF signal
transmitted by the TCM to provide overrun clutch control (engine
brake control).
When this solenoid valve is “ON”, the pilot pressure drain port
closes. When it is “OFF”, the drain port opens.
During the solenoid valve “ON” pilot pressure is applied to the end
face of the overrun clutch control valve.
OVERRUN CLUTCH CONTROL VALVE OPERATION
When the solenoid valve is “ON”, pilot pressure is applied to the
overrun clutch control valve. This pushes up the overrun clutch con-
trol valve. The line pressure is then shut off so that the clutch does
not engage. Only in “1” position, however, 1 range pressure is
applied to overrun clutch control valve, resulting in valve moving
downward and clutch engaged.
When the solenoid valve is “OFF”, pilot pressure is not generated. At
this point, the overrun clutch control valve moves downward by
spring force. As a result, overrun clutch operation pressure is pro-
vided by the overrun clutch reducing valve. At overrun clutch reduc-
ing valve in “D” position, the hydraulic pressure is reduced to a level
that balances the spring force. This is sent to overrun clutch control
valve and becomes the operating pressure of overrun clutch which is
engaged at all times. In “2” position and “1” position, overrun clutch
reducing valve is pushed down by 2 range pressure. Line pressure is
directly sent to overrun clutch control valve and becomes the operat-
ing pressure of overrun clutch which is engaged at all times.
SCIA7186E
SAT015J
SCIA7172E
TM-344
< FUNCTION DIAGNOSIS >[TYPE 2 (4AT: RE4F03B)]
A/T CONTROL SYSTEM
Control Valve
INFOID:0000000001714318
FUNCTION OF CONTROL VALVES
Centrifugal Cancel MechanismINFOID:0000000001714319
FUNCTION
The centrifugal cancel mechanism is a mechanism to cancel the centrifugal hydraulic pressure instead of the
conventional check balls. It cancels the centrifugal hydraulic pressure which is generated as high clutch drum
rotates, and it allows for preventing high clutch from dragging and for providing stable high clutch piston press-
ing force in all revolution speeds.
STRUCTURE/OPERATION
Valve name Function
Pressure regulator valve, plug and sleeve
plugRegulates 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 pres-
sure-modifier pressure (signal pressure) which controls optimum line pressure for all driv-
ing 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 upshifting (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 upshifting (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 D
4. (Interlocking occurs if the overrun clutch engages
during D
4.)
1st reducing valve Reduces low & reverse brake pressure to dampen engine-brake shock when downshift-
ing from the 1st position 1
2 to 11.
Overrun clutch reducing valve Reduces oil pressure directed to the overrun clutch and prevents engine-brake shock.
In the 1st and 2nd 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 sleeveActivates 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 Lessens the shock find when the 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 downshifting.
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 a little heat is generated, saves the volume of
cooler flow, and stores the oil pressure for lock-up.
TM-348
< FUNCTION DIAGNOSIS >[TYPE 2 (4AT: RE4F03B)]
DIAGNOSIS SYSTEM (TCM)
DIAGNOSIS SYSTEM (TCM)
CONSULT-III Function (TRANSMISSION)INFOID:0000000001714329
CONSULT-III can display each diagnostic item using the diagnostic test models shown following.
SELF-DIAGNOSTIC RESULT MODE
Operation Procedure
After performing TM-38, "Diagnosis Procedure without CONSULT-III", place check marks for results on the
XX-XX, "*****"
. Reference pages are provided following the items.
Display Items List
TCM diagnostic mode Description
WORK SUPPORTSupports inspections and adjustments. Commands are transmitted to the TCM for setting the status
suitable for required operation, input/output signals are received from the TCM and received data is
displayed.
SELF-DIAG RESULTS Displays TCM self-diagnosis results.
DATA MONITOR Displays TCM input/output data in real time.
CAN DIAG SUPPORT MNTR The result of transmit/receive diagnosis of CAN communication can be read.
ACTIVE TEST Operation of electrical loads can be checked by sending drive signal to them.
FUNCTION TEST Conducted by CONSULT-III instead of a technician to determine whether each system is “OK” or “NG”.
ECU PART NUMBER TCM part number can be read.
Items (CONSULT-III screen terms) Malfunction is detected when... Reference page
VHCL SPEED SEN-A/T TCM does not receive the proper voltage signal from the sensor.XX-XX, "*****"
VHCL SPEED SEN-MTR TCM does not receive the proper voltage signal from the sensor.XX-XX, "*****"
SHIFT SOLENOID/V A TCM detects an improper voltage drop when it tries to operate the sole-
noid valve.XX-XX, "*****"
SHIFT SOLENOID/V B TCM detects an improper voltage drop when it tries to operate the sole-
noid valve.XX-XX, "*****"
OVERRUN CLUTCH S/V TCM detects an improper voltage drop when it tries to operate the sole-
noid valve.XX-XX, "*****"
T/C CLUTCH SOL/V TCM detects an improper voltage drop when it tries to operate the sole-
noid valve.XX-XX, "*****"
BATT/FLUID TEMP SEN TCM receives an excessively low or high voltage from the sensor.XX-XX, "*****"
ENGINE SPEED SIG TCM does not receive the proper voltage signal from the ECM.XX-XX, "*****"
TURBINE SENSOR TCM does not receive proper voltage signal from sensor.XX-XX, "*****"
LINE PRESSURE S/V TCM detects an improper voltage drop when it tries to operate the sole-
noid valve.XX-XX, "*****"
CAN COMM CIRCUIT When malfunction is detected in CAN communication line.XX-XX, "*****"
A/T 1ST GR FNCTN A/T cannot be shifted to the 1st gear position even if electrical circuit is
good.XX-XX, "*****"
A/T 2ND GR FNCTN A/T cannot be shifted to the 2nd gear position even if electrical circuit is
good.XX-XX, "*****"
A/T 3RD GR FNCTN A/T cannot be shifted to the 3rd gear position even if electrical circuit is
good.XX-XX, "*****"
A/T 4TH GR FNCTN A/T cannot be shifted to the 4th gear position even if electrical circuit is
good.XX-XX, "*****"
A/T TCC S/V FNCTN A/T cannot perform lock-up even if electrical circuit is good.XX-XX, "*****"
CONTROL UNIT (RAM) TCM memory (RAM) is malfunctioning.XX-XX, "*****"
CONTROL UNIT (ROM) TCM memory (ROM) is malfunctioning.XX-XX, "*****"
DIAGNOSIS SYSTEM (TCM)
TM-349
< FUNCTION DIAGNOSIS >[TYPE 2 (4AT: RE4F03B)]
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DATA MONITOR MODE
Display Items List
X: Standard, —: Not applicable, : Option
INITIAL START This is not a malfunction message (Whenever shutting off a power sup-
ply to the TCM, this message appears on the screen). Refer to XX-XX,
"*****".XX-XX, "*****"
No failure
(NO SELF DIAGNOSTIC FAILURE
INDICATED FURTHER TESTING
MAY BE REQUIRED) No failure has been detected. — Items (CONSULT-III screen terms) Malfunction is detected when... Reference page
Monitored item (Unit)Monitor Item Selection
Remarks
TCM INPUT
SIGNALSMAIN SIG-
NALSSELEC-
TION FROM
MENU
VHCL/S SE-A/T (km/h) X — Revolution sensor
VHCL/S SE-MTR (km/h) X —Vehicle speed display may not be accu-
rate under approx. 10 km/h (6 mph). It
may not indicate 0 km/h (0 mph) when
vehicle is stationary.
THRTL POS SEN (V) X —
FLUID TEMP SE (V) X —
BATTERY VOLT (V) X —
ENGINE SPEED (rpm) X X
TURBINE REV (rpm) X —
OVERDRIVE SW (ON/OFF) X —
PN POSI SW (ON/OFF) X —
R POSITION SW (ON/OFF) X —
D POSITION SW (ON/OFF) X —
2 POSITION SW (ON/OFF) X —
1 POSITION SW (ON/OFF) X —
ASCD-CRUISE (ON/OFF) X —
Signal input with CAN communication.
ASCD-OD CUT (ON/OFF) X —
KICKDOWN SW (ON/OFF) X —
Not mounted but displayed.
POWERSHIFT SW (ON/OFF) X —
CLOSED THL/SW (ON/OFF) X —
Signal input with CAN communication.
W/O THRL/P-SW (ON/OFF) X —
*SHIFT S/V A (ON/OFF) — —
Displays status of check signal (reinput
signal) for TCM control signal output. Re-
mains unchanged when solenoid valves
are open or shorted. *SHIFT S/V B (ON/OFF) — —
*OVRRUN/C S/V (ON/OFF) — —
HOLD SW (ON/OFF) X — Not mounted but displayed.
BRAKE SW (ON/OFF) X — Stop lamp switch
GEAR — XGear position recognized by the TCM up-
dated after gear-shifting
TM-350
< FUNCTION DIAGNOSIS >[TYPE 2 (4AT: RE4F03B)]
DIAGNOSIS SYSTEM (TCM)
Diagnosis Procedure without CONSULT-III
INFOID:0000000001714330
TCM SELF-DIAGNOSTIC PROCEDURE
Description
If a malfunction occurs in electrical system, turning ignition switch ON will illuminate OD OFF indicator lamp for
2 seconds. To detect a malfunction, entering a self-diagnosis start signal retrieves information on malfunctions
from memory and indicates malfunction by blinking OD OFF indicator lamp.
Diagnostic Procedure
1.CHECK OD OFF INDICATOR LAMP
1. Park vehicle on flat surface.
SLCT LVR POSI — XSelector lever position is recognized by
the TCM.
For fail-safe operation, the specific value
used for control is displayed.
VEHICLE SPEED (km/h) — X Vehicle speed recognized by the TCM.
THROTTLE POSI (0.0/8) — XDegree of opening for accelerator recog-
nized by the TCM
For fail-safe operation, the specific value
used for control is displayed.
LINE PRES DTY (%) — X
TCC S/V DUTY (%) — X
SHIFT S/V A (ON/OFF) — X
SHIFT S/V B (ON/OFF) — X
OVERRUN/C S/V (ON/OFF) — X
SELF-D DP LMP (ON/OFF) — X
TC SLIP RATIO (0.000) — —
TC SLIP SPEED (rpm) — —Difference between engine speed and
torque converter input shaft speed
Voltage (V) — —Displays the value measured by the volt-
age probe.
Frequency (Hz) — —
The value measured by the pulse probe
is displayed. DUTY-HI (high) (%) — —
DUTY-LOW (low) (%) — —
PLS WIDTH-HI (ms) — —
PLS WIDTH-LOW (ms) — —Monitored item (Unit)Monitor Item Selection
Remarks
TCM INPUT
SIGNALSMAIN SIG-
NALSSELEC-
TION FROM
MENU