TM-14
< FUNCTION DIAGNOSIS >[TYPE 1 (4AT: RE4F03B)]
A/T CONTROL SYSTEM
Shift Mechanism
INFOID:0000000001694421
CONSTRUCTION
FUNCTION OF CLUTCH AND BRAKE
CLUTCH AND BAND CHART
1. Torque converter 2. Oil pump 3. Input shaft
4. Brake band 5. Reverse clutch 6. High clutch
7. Front sun gear 8. Front pinion gear 9. Front internal gear
10. Front planetary carrier 11. Rear sun gear 12. Rear pinion gear
13. Rear internal gear 14. Rear planetary carrier 15. Forward clutch
16. Forward one-way clutch 17. Overrun clutch 18. Low one-way clutch
19. Low & reverse brake 20. Parking pawl 21. Parking gear
22. Output shaft 23. Idle gear 24. Output gear
SAT998I
Clutch and brake components Abbr. Function
5Reverse clutch R/C To transmit input power to front sun gear 7.
6High clutch H/C To transmit input power to front planetary carrier 10.
15Forward clutch F/C To connect front planetary carrier 10 with forward one-way clutch 16.
17Overrun clutch O/C To connect front planetary carrier 10 with rear internal gear 13.
4Brake band B/B To lock front sun gear 7.
16Forward one-way clutch F/O.CWhen forward clutch 15 is engaged, to stop rear internal gear 13 from rotating in
opposite direction against engine revolution.
18Low one-way clutch L/O.CTo stop front planetary carrier 10 from rotating in opposite direction against en-
gine revolution.
19Low & reverse brake L & R/B To lock front planetary carrier 10.
Shift posi-
tionR/C
5H/C
6F/C
15O/C
17Band servo
F/O.C
16L/O.C
18L&R/B
19Lock-
upRemarks
2nd
apply3rd re-
lease4th ap-
ply
PPA R K
POSITION
RREVERSE
POSITION
A/T CONTROL SYSTEM
TM-15
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*1: Operates when OD OFF. (OD OFF indicator lamp is on.)
*2: Oil pressure is applied to both 2nd “apply” side and 3rd “release” side of band servo piston. However, brake band does not contract
because oil pressure area on the “release” side is greater than that on the “apply” side.
*3: Oil pressure is applied to 4th “apply” side on condition *2 above, and brake band contracts.
*4: A/T will not shift to 4th when OD OFF. (OD OFF indicator lamp is on.)
: Operates.
A: Operates when throttle opening is less than specification**, activating engine brake.
B: Operates during “progressive” acceleration.
C: Operates but does not affect power transmission.
D: Operates when throttle opening is less than specification**, but does not affect engine brake.
- **: Overrun clutch remains in engaged condition when throttle opening is less than 1/16.
POWER TRANSMISSION
“N” and “P” Positions
“N” position
Power from the input shaft is not transmitted to the output shaft because the clutches do not operate.
“P” position
NNEUTRAL
POSITION
D*41st *1D B B
2nd *1A BAutomatic
shift
3rd *1A *2C C B
*11 ⇔ 2 ⇔ 3
⇔ 4
4th C *3C C
21stBB
Automatic
shift
1 ⇔ 2 ⇐ 3 2ndB
3rd *2C C B
11stBB
Locks (held
stationary)
in 1st speed
1 ⇐ 2 ⇐ 3 2ndB
3rd *2C C B Shift posi-
tionR/C
5H/C
6F/C
15O/C
17Band servo
F/O.C
16L/O.C
18L&R/B
19Lock-
upRemarks
2nd
apply3rd re-
lease4th ap-
ply
A/T CONTROL SYSTEM
TM-25
< FUNCTION DIAGNOSIS >[TYPE 1 (4AT: RE4F03B)]
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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 figure 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 ControlINFOID:0000000001694427
The torque converter clutch piston in the torque converter is locked to eliminate torque converter slip and 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 torque converter clutch piston.
CONDITIONS FOR LOCK-UP OPERATION
When vehicle is driven in 3rd and 4th gear positions, 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
Gear position 1 2 3 4
Shift solenoid valve A ON (Closed) OFF (Open) OFF (Open) ON (Closed)
Shift solenoid valve B ON (Closed) ON (Closed) OFF (Open) OFF (Open)
SAT009J
OD ON OFF
Selector lever “D” position
Gear position D
4D3
Vehicle speed sensor More than set value
Throttle position sensor Less than set opening
Closed throttle position switch OFF
A/T fluid temperature sensor More than 40°C (104°F)
TM-28
< FUNCTION DIAGNOSIS >[TYPE 1 (4AT: RE4F03B)]
A/T CONTROL SYSTEM
Control Valve
INFOID:0000000001694429
FUNCTION OF CONTROL VALVES
Centrifugal Cancel MechanismINFOID:0000000001694419
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.
A/T CONTROL SYSTEM
TM-29
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A centrifugal cancel housing is provided to cancel the clutch housing pressure. The centrifugal cancel housing
is always filled with ATF from the dedicated fluid passage of oil pump.
When Clutch Pressure Is Not Applied
As high clutch drum rotates, a centrifugal force applies to the remaining ATF in clutch housing to push high
clutch piston. However, on the other hand, the centrifugal force also applies to ATF filled in centrifugal cancel
housing, resulting in a force that pushes high clutch piston back. Consequently the high clutch piston does not
move because both forces cancel each other, and thus high clutch is prevented from dragging.
When Clutch Pressure Is Applied
Clutch pressure that applies to clutch housing overcomes the fluid pressure and spring force of the opposing
centrifugal housing to push high clutch piston, and high clutch is engaged. At this time, the centrifugal force
caused by the revolution speed of high clutch drum has no impact any more since the centrifugal force that
applies to the clutch pressure of clutch housing is canceled by the centrifugal force that applies to centrifugal
cancel housing. As a result, high clutch piston pressing force is always stable in all revolution speeds, and
thus smooth shifting characteristics are achieved.
SCIA6832E
SCIA6833E
TM-50
< COMPONENT DIAGNOSIS >[TYPE 1 (4AT: RE4F03B)]
DTC P0710 A/T FLUID TEMPERATURE SENSOR CIRCUIT
OK or NG
OK >> GO TO 5.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
5.CHECK A/T FLUID TEMPERATURE SENSOR WITH TERMINAL CORD ASSEMBLY
1. Turn ignition switch OFF.
2. Disconnect terminal cord assembly harness connector in engine room.
3. Check resistance between terminal cord assembly harness con-
nector terminals.
4. Reinstall any part removed.
OK or NG
OK >> GO TO 6.
NG >> Repair or replace damaged parts.
6.DETECT MALFUNCTIONING ITEM
1. Remove oil pan. Refer to TM-191, "
Control Valve Assembly and Accumulators".
2. Check the following.
- A/T fluid temperature sensor
Check resistance between terminal cord assembly harness con-
nector terminals while changing temperature as shown.
- Harness of terminal cord assembly for short or open
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
7.CHECK DTC
Perform TM-48, "
DTC Confirmation Procedure".
OK or NG
OK >>INSPECTION END
NG >> GO TO 8.
8.CHECK TCM
1. Check TCM input/output signal. Refer to TM-119, "
Reference Value".
2. If NG, recheck TCM pin terminals for damage or loose connection with harness connector.
OK or NG
OK >>INSPECTION END
NG >> Repair or replace damaged parts.
Component InspectionINFOID:0000000001694298
A/T FLUID TEMPERATURE SENSOR
Temperature [°C (°F)] Resistance (Approx.)
20 (68) 2.5 kΩ
80 (176) 0.3 kΩ
SCIA4948E
Temperature [°C (°F)] Resistance (Approx.)
20 (68) 2.5 kΩ
80 (176) 0.3 kΩ
SAT298F
DTC P0710 A/T FLUID TEMPERATURE SENSOR CIRCUIT
TM-51
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Remove oil pan. Refer to TM-191, "Control Valve Assembly and
Accumulators".
Check resistance between terminal cord assembly harness con-
nector terminals while changing temperature as shown.
Temperature [°C (°F)] Resistance (Approx.)
20 (68) 2.5 kΩ
80 (176) 0.3 kΩ
SAT298F
TM-68
< COMPONENT DIAGNOSIS >[TYPE 1 (4AT: RE4F03B)]
DTC P0734 A/T 4TH GEAR FUNCTION
DTC P0734 A/T 4TH GEAR FUNCTION
DescriptionINFOID:0000000001694328
This malfunction will not be detected while the OD OFF indicator lamp is indicating another self-diagnosis
malfunction.
This malfunction is detected when the A/T does not shift into fourth gear position or the torque converter
clutch does not lock up as instructed by the TCM. This is not caused by electrical malfunction (circuits open
or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation,
malfunctioning oil pump or torque converter clutch, etc.
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000001694329
Remarks: Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000001694330
This is an OBD self-diagnostic item.
Diagnostic trouble code “P0734 A/T 4TH GR FNCTN” with CONSULT-III is detected when A/T cannot be
shifted to the 4th gear position even if electrical circuit is good.
This diagnosis monitors actual gear position by checking the torque converter slip ratio calculated by TCM
as follows:
Torque converter slip ratio = A x C/B
A: Output shaft revolution signal from revolution sensor
B: Engine speed signal from ECM
C: Gear ratio determined as gear position which TCM supposes
If the actual gear position is much lower than the position (4th) supposed by TCM, the slip ratio will be much
less than normal. In case the ratio does not reach the specified value, TCM judges this diagnosis malfunc-
tion.
This malfunction will be caused when shift solenoid valve A is stuck open or shift solenoid valve B is stuck
closed.
Gear positions supposed by TCM are as follows.
In case of gear position with no malfunctions: 1, 2, 3 and 4 positions
In case of gear position with shift solenoid valve A stuck open: 2, 2, 3 and 3* positions
In case of gear position with shift solenoid valve B stuck closed: 1, 2, 2 and 1* positions to each gear position
above
*: “P0734 A/T 4TH GR FNCTN” is detected.
Possible CauseINFOID:0000000001694331
Shift solenoid valve A
Shift solenoid valve B
Line pressure solenoid valve
Each clutch
Hydraulic control circuit
DTC Confirmation ProcedureINFOID:0000000001694332
CAUTION:
Always drive vehicle at a safe speed.
If performing this “DTC Confirmation Procedure” again, always turn ignition switch OFF and wait at
least 10 seconds before continuing.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
Gear position 1 2 3 4
Shift solenoid valve A ON (Closed) OFF (Open) OFF (Open) ON (Closed)
Shift solenoid valve B ON (Closed) ON (Closed) OFF (Open) OFF (Open)
Item name Condition Display value (Approx.)
LINE PRES DTYSmall throttle opening (Low line pressure) ⇔ Large
throttle opening (High line pressure)0% ⇔ 94%