A/T CONTROL SYSTEM
AT-35
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Revision: 2006 January2006 M35/M45
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.
BLIPPING CONTROL
This system makes transmission clutch engage readily by controlling (synchronizing) engine revolution
according to the (calculation of) engine revolution after shifting down.
“BLIPPING CONTROL” functions.
–When downshifting by accelerator pedal depression at “D” position.
–When downshifting under the manual mode.
TCM selects “BLIPPING CONTROL” or “NORMAL SHIFT CONTROL” according to the gear position, the
select lever position, the engine torque and the speed when accelerating by pedal depression.
Revolution control demand signal is transmitted from TCM to ECM under “BLIPPING CONTROL”.
TCM synchronizes engine revolution according to the revolution control demand signal.
PCIA0013E
AT-38
A/T CONTROL SYSTEM
Revision: 2006 January2006 M35/M45
Engine Brake ControlNCS001JV
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.
Control ValveNCS001JW
FUNCTION OF CONTROL VALVE
SCIA1520E
Name Function
Torque converter regulator valveIn 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 sleeveAdjusts the oil discharged from the oil pump to the optimum pressure (line pressure) for
the driving state.
Front brake control valveWhen 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 valveAdjusts 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 AAdjusts the line pressure and produces the constant pressure (pilot pressure) required
for line pressure control, shift change control, and lock-up control.
Pilot valve BAdjusts 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 valveWhen 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 valveWhen 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.)
TROUBLE DIAGNOSIS
AT-53
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Revision: 2006 January2006 M35/M45
Inspections before Trouble DiagnosisNCS001K7
A/T FLUID CHECK
A/T Fluid Leakage and A/T Fluid Level Check
Inspect for A/T fluid leakage and check the A/T fluid level. Refer to AT- 1 3 , "Checking A/T Fluid" .
A/T Fluid Condition Check
Inspect the A/T fluid condition.
STALL TEST
Stall Test Procedure
1. Inspect the amount of engine oil. Replenish the engine oil if necessary.
2. Drive for about 10 minutes to warm up the vehicle so that the A/
T fluid temperature is 50 to 80
C (122 to 176F). Inspect the
amount of ATF. Replenish if necessary.
3. Securely engage the parking brake so that the tires do not turn.
4. Engine start, apply foot brake, and place selector lever in “D”
position.
Fluid condition Conceivable Cause Required Operation
Varnished (viscous
varnish state)Clutch, brake
scorchedReplace the ATF and check the A/T
main unit and the vehicle for mal-
functions (wire harnesses, cooler
pipes, etc.)
Milky white or cloudy Water in the fluidReplace the ATF and check for
places where water is getting in.
Large amount of metal
powder mixed inUnusual wear of
sliding parts within
A/TReplace the ATF and check for
improper operation of the A/T.
SAT638A
SAT647B
SCIA7463E
SCIA6787E
TROUBLE DIAGNOSIS
AT-55
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Revision: 2006 January2006 M35/M45
LINE PRESSURE TEST
Line Pressure Test Port
Line Pressure Test Procedure
1. Inspect the amount of engine oil and replenish if necessary.
2. Drive the car for about 10 minutes to warm it up so that the ATF reaches in range of 50 to 80
C (122 to
176
F), then inspect the amount of ATF and replenish if necessary.
NOTE:
The A/T fluid temperature rises in range of 50 to 80
C (122 to 176F) during 10 minutes of driving.
3. Remove the front propeller shaft from vehicle (with AWD models). Refer to PR-5, "
Removal and Installa-
tion" .
4. After warming up remove the oil pressure detection plug and
install the oil pressure gauge [ST2505S001(J-34301-C)].
CAUTION:
When using the oil pressure gauge, be sure to use the O-
ring attached to the oil pressure detection plug.
5. Securely engage the parking brake so that the tires do not turn.
6. Start the engine, then measure the line pressure at both idle and
the stall speed.
CAUTION:
Keep the brake pedal pressed all the way down during
measurement.
When measuring the line pressure at the stall speed,
refer to AT- 5 3 , "
STALL TEST" .
7. After the measurements are complete, install the oil pressure
detection plug and tighten to the specified torque.
SCIA2187E
SCIA5309E
SCIA7463E
: 7.3 Nꞏm (0.74 kg-m, 65 in-lb)SAT493G
AT-56
TROUBLE DIAGNOSIS
Revision: 2006 January2006 M35/M45
CAUTION:
Do not reuse O-ring.
Apply ATF to O-ring.
Line Pressure
Judgement of Line Pressure Test
Engine speedLine pressure [kPa (kg/cm
2 , psi)]
“R” position “D”, “M” positions
At idle speed 425 - 465 (4.3 - 4.7, 62 - 67) 379 - 428 (3.9 - 4.4, 55 - 62)
At stall speed 1,605 - 1,950 (16.4 - 19.9, 233 - 283) 1,310 - 1,500 (13.4 - 15.3, 190 - 218)
Judgement Possible cause
Idle speedLow for all positions
(“P”, “R”, “N”, “D”, “M”)Possible causes include malfunctions in the pressure supply system and low oil pump out-
put.
For example
Oil pump wear
Pressure regulator valve or plug sticking or spring fatigue
Oil strainer oil pump pressure regulator valve passage oil leak
Engine idle speed too low
Only low for a specific
positionPossible causes include an oil pressure leak in a passage or device related to the position
after the pressure is distributed by the manual valve.
HighPossible causes include a sensor malfunction or malfunction in the line pressure adjustment
function.
For example
Accelerator pedal position signal malfunction
A/T fluid temperature sensor malfunction
Line pressure solenoid malfunction (sticking in OFF state, filter clog, cut line)
Pressure regulator valve or plug sticking
Stall speedOil pressure does not
rise higher than the oil
pressure for idle.Possible causes include a sensor malfunction or malfunction in the pressure adjustment
function.
For example
Accelerator pedal position signal malfunction
TCM breakdown
Line pressure solenoid malfunction (shorting, sticking in ON state)
Pressure regulator valve or plug sticking
Pilot valve sticking or pilot filter clogged
The pressure rises, but
does not enter the stan-
dard position.Possible causes include malfunctions in the pressure supply system and malfunction in the
pressure adjustment function.
For example
Accelerator pedal position signal malfunction
Line pressure solenoid malfunction (sticking, filter clog)
Pressure regulator valve or plug sticking
Pilot valve sticking or pilot filter clogged
Only low for a specific
positionPossible causes include an oil pressure leak in a passage or device related to the position
after the pressure is distributed by the manual valve.
TROUBLE DIAGNOSIS
AT-59
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Revision: 2006 January2006 M35/M45
Cruise Test - Part 1NCS001KA
1. CHECK STARTING OUT FROM D1
1. Drive the vehicle for about 10 minutes to warm up the engine oil and A/T fluid.
Appropriate temperature for the A/T fluid: 50 to 80
C (122 to 176F)
2. Park the vehicle on a level surface.
3. Move selector lever to “P” position.
4. Start the engine.
5. Move selector lever to “D” position.
6. Press the accelerator pedal about half way down to accelerate the vehicle.
With CONSULT-II
Read the gear position. Refer to AT- 9 6 , "
DATA MONITOR MODE" .
Starts from D1?
YES >> GO TO 2.
NO >> Enter a check mark at “Vehicle Cannot Be Started from D1” on the AT- 4 8 , "
DIAGNOSTIC WORK-
SHEET" , then continue the road test.
2. CHECK SHIFT-UP D1 D2
Press down the accelerator pedal about half-way and inspect if the vehicle shifts up (D1
D2) at the appro-
priate speed.
Refer to AT- 6 3 , "Vehicle Speed at Which Gear Shifting Occurs" .
With CONSULT-II
Read the gear position, throttle degree of opening and vehicle speed. Refer to AT- 9 6 , "
DATA MONITOR
MODE" .
Does the A/T shift-up D1
D2 at the correct speed?
YES >> GO TO 3.
NO >> Enter a check mark at “A/T Does Not Shift: D1
D2” on the AT- 4 8 , "DIAGNOSTIC WORK-
SHEET" , then continue the road test.
3. CHECK SHIFT-UP D2 D3
Press down the accelerator pedal about half-way and inspect if the vehicle shifts up (D2
D3) at the appro-
priate speed.
Refer to AT- 6 3 , "Vehicle Speed at Which Gear Shifting Occurs" .
With CONSULT-II
Read the gear position, throttle degree of opening and vehicle speed. Refer to AT- 9 6 , "
DATA MONITOR
MODE" .
Does the A/T shift-up D2
D3 at the correct speed?
YES >> GO TO 4.
NO >> Enter a check mark at “A/T Does Not Shift: D2
D3” on the AT- 4 8 , "DIAGNOSTIC WORK-
SHEET" , then continue the road test.
4. CHECK SHIFT-UP D3 D4
Press down the accelerator pedal about half-way and inspect if the vehicle shifts up (D3
D4) at the appro-
priate speed.
Refer to AT- 6 3 , "Vehicle Speed at Which Gear Shifting Occurs" .
With CONSULT-II
Read the gear position, throttle degree of opening and vehicle speed. Refer to AT- 9 6 , "
DATA MONITOR
MODE" .
Does the A/T shift-up D3
D4 at the correct speed?
YES >> GO TO 5.
NO >> Enter a check mark at “A/T Does Not Shift: D3
D4” on the AT- 4 8 , "DIAGNOSTIC WORK-
SHEET" , then continue the road test.
AT-72
TROUBLE DIAGNOSIS
Revision: 2006 January2006 M35/M45
22
Slips/Will
Not
EngageWhen “D” or “M” posi-
tion, remains in 5th
gear.ON vehicle1. A/T fluid level and stateAT- 5 3
2. Vehicle speed sensorꞏA/T and vehicle speed sensorꞏMTRAT- 11 9,
AT- 1 4 0
3. ATF pressure switch 1 and front brake solenoid valveAT- 1 7 2
,
AT- 1 5 1
4. Line pressure testAT- 5 5
5. CAN communication lineAT- 1 0 5
6. Control valve with TCMAT- 2 3 6
OFF vehicle7. Front brake (brake band)AT- 2 9 88. Input clutchAT- 3 2 3
9. Gear systemAT- 2 7 8
10. High and low reverse clutchAT- 3 3 5
23Vehicle cannot be
started from D
1 .
Refer to AT-199,
"Vehicle Cannot Be
Started from D1" .ON vehicle1. A/T fluid level and stateAT- 5 3
2. Accelerator pedal position sensorAT- 1 3 2
3. Line pressure testAT- 5 5
4. CAN communication lineAT- 1 0 5
5. Control valve with TCMAT- 2 3 6
OFF vehicle6. Torque converterAT- 2 9 8
7. Oil pump assemblyAT- 3 1 8
8. 3rd one-way clutchAT- 3 2 1
9. 1st one-way clutch AT- 3 2 9
10. Gear systemAT- 2 7 8
11. Reverse brakeAT- 2 9 8
12. Forward one-way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
AT-17, "
Cross-Sectional View (VQ35DE Models for 2WD)" ,
AT-18, "
Cross-Sectional View (VK45DE Models for 2WD)" o r
AT-19, "
Cross-Sectional View (AWD Models)" .)AT- 2 9 8
13. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT-17,
"Cross-Sectional View (VQ35DE Models for 2WD)" , AT-18,
"Cross-Sectional View (VK45DE Models for 2WD)" o r AT-19,
"Cross-Sectional View (AWD Models)" .)AT- 2 9 8
24Does not lock-up.
Refer to AT-209, "A/T
Does Not Lock-Up" .ON vehicle1. A/T fluid level and stateAT- 5 3
2. Line pressure testAT- 5 5
3. Engine speed signalAT- 1 2 4
4. Turbine revolution sensorAT- 11 7
5. Torque converter clutch solenoid valveAT- 1 2 6
6. CAN communication lineAT- 1 0 5
7. Control valve with TCMAT- 2 3 6
OFF vehicle8. Torque converterAT- 2 9 89. Oil pump assemblyAT- 3 1 8
No. Item Symptom Condition Diagnostic ItemReference
page
TROUBLE DIAGNOSIS
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Revision: 2006 January2006 M35/M4525
Slips/Will
Not
EngageDoes not hold lock-up
condition.
Refer to AT-210, "A/T
Does Not Hold Lock-
Up Condition" .ON vehicle1. A/T fluid level and stateAT- 5 3
2. Line pressure testAT- 5 5
3. Engine speed signalAT-124
4. Turbine revolution sensorAT- 11 7
5. Torque converter clutch solenoid valveAT-126
6. CAN communication lineAT-105
7. Control valve with TCMAT-236
OFF vehicle8. Torque converterAT-2989. Oil pump assemblyAT-318
26Lock-up is not
released.
Refer to AT-212,
"Lock-Up Is Not
Released" .ON vehicle1. A/T fluid level and stateAT- 5 3
2. Line pressure testAT- 5 5
3. Engine speed signalAT-124
4. Turbine revolution sensorAT- 11 7
5. Torque converter clutch solenoid valveAT-126
6. CAN communication lineAT-105
7. Control valve with TCMAT-236
OFF vehicle8. Torque converterAT-2989. Oil pump assemblyAT-318
27No shock at all or the
clutch slips when
vehicle changes
speed D
1 D2 or
M
1 M2 . ON vehicle1. A/T fluid level and stateAT- 5 3
2. Vehicle speed sensorꞏA/T and vehicle speed sensorꞏMTRAT- 11 9,
AT-140
3. ATF pressure switch 5 and direct clutch solenoid valveAT-176,
AT-155
4. CAN communication lineAT-105
5. Line pressure testAT- 5 5
6. Control valve with TCMAT-236
OFF vehicle7. Torque converterAT-298
8. Oil pump assemblyAT-318
9. 3rd one-way clutchAT-321
10. Gear systemAT-278
11. Direct clutchAT-337
12. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT-17,
"Cross-Sectional View (VQ35DE Models for 2WD)" , AT- 1 8 ,
"Cross-Sectional View (VK45DE Models for 2WD)" o r AT- 1 9 ,
"Cross-Sectional View (AWD Models)" .)AT-298
No. Item Symptom Condition Diagnostic ItemReference
page