2006 INFINITI QX56 transmission fluid

AT-30
A/T CONTROL SYSTEM
Revision: November 20092006 QX56
TCM FunctionECS00CDW
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 sensor
Closed throttle position signal
Wide open throttle position signal
Engine speed signal
A/T fluid temperature sensor
Revolution sensor
Vehicle speed signal
Stop lamp switch signal
Turbine revolution sensor
1st position switch signal
4th position switch signal
ATF pressure switch signal
Tow mode switch signal 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
Starter relay
Back-up lamp relay
SCIA5624E

A/T CONTROL SYSTEMAT-31
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Revision: November 2009 2006 QX56
CAN CommunicationECS00CDX
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-26,
"CAN COMMUNICATION" .
Input/Output Signal of TCMECS00CDY
*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: 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
(*4)XXXXXXX
Vehicle speed sensor A/T
(revolution sensor) XXXX
XX
Vehicle speed sensor MTR
(*1) (*4)XXXX X
Closed throttle position signal
(*4)(*2) X (*2) X X (*2) XX
Wide open throttle position signal
(*4)(*2) X (*2) X (*2) XX
Turbine revolution sensor 1 XX X XX
Turbine revolution sensor 2
(for 4th speed only) XX
XXX
Engine speed signals
(*4)XX
PNP s witch XXXXXXX
A/T fluid temp eratu re senso rs 1, 2XXXXXXX
ASCD Operation signal
(*4)XXXX
Overdrive cancel
signal
(*4)XX X
TCM power supply voltage signal XXXXX 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
L in e p re ssu re s olen oid XXXXXXX
TCC solenoid XX X
Sta rter rela y XX

TROUBLE DIAGNOSISAT-51
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Revision: November 2009 2006 QX56
Inspections Before Trouble DiagnosisECS00CEE
A/T FLUID CHECK
Fluid Leakage and Fluid Level Check

Inspect for fluid leakage and check the fluid level. Refer to AT- 1 2 , "Changing Automatic Transmission
Fluid (ATF)" .
Fluid Condition Check
Inspect the 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 176 °F). 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.
5. While holding down the foot brake, gradually press down the accelerator pedal.
6. Quickly read off the stall speed, then quickly remove your foot from the accelerator pedal.
CAUTION:
Do not hold down the accelerator pedal for more than 5 sec-
onds during this test.
7. Move the selector lever to the “N” 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
in Unusual wear of
sliding parts within
A/T
Replace the ATF and check for
improper operation of the A/T.
SAT638A
SAT647B
SCIA1224E
SAT514G

TROUBLE DIAGNOSISAT-71
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Revision: November 2009 2006 QX56
30
Slips/Will
Not
engage No shock at all or the
clutch slips when
vehicle changes
speed D
4 →
D5 . ON vehicle 1. Fluid level and state
AT- 5 1
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT-132
3. ATF pressure switch 1 and front brake solenoid valve AT-159,
AT-143
4. ATF pressure switch 5 and direct clutch solenoid valve AT-163,
AT-147
5. CAN communication line AT- 9 6
6. Line pressure testAT- 5 2
7. Control valve with TCMAT-230
OFF vehicle8. Torque converter
AT-264
9. Oil pump assemblyAT-282
10. Front brake (brake band)AT-264
11. Input clutchAT-286
12. Gear systemAT-250
13. High and low reverse clutchAT-296
31When you press the
accelerator pedal and
shift speed D5 →
D4
the engine idles or the
transmission slips. ON vehicle
1. Fluid level and state
AT- 5 1
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT-132
3. ATF pressure switch 1 and front brake solenoid valve AT-159,
AT-143
4. ATF pressure switch 5 and direct clutch solenoid valve AT-163,
AT-147
5. CAN communication line AT- 9 6
6. Line pressure testAT- 5 2
7. Control valve with TCMAT-230
OFF vehicle8. Torque converter
AT-264
9. Oil pump assemblyAT-282
10. Input clutchAT-286
11. Gear systemAT-250
12. High and low reverse clutchAT-296
13. Direct clutchAT-298
No. ItemsSymptom Condition Diagnostic ItemReference
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AT-72
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
32
Slips/Will
Not
engage When you press the
accelerator pedal and
shift speed D4
→ D3
the engine idles or the
transmission slips. ON vehicle
1. Fluid level and state
AT- 5 1
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT- 1 3 2
3. ATF pressure switch 3 and input clutch solenoid valve AT- 1 6 1,
AT- 1 3 9
4. ATF pressure switch 1 and front brake solenoid valve AT- 1 5 9,
AT- 1 4 3
5. CAN communication line AT- 9 6
6. Line pressure testAT- 5 2
7. Control valve with TCMAT- 2 3 0
OFF vehicle8. Torque converter
AT- 2 6 4
9. Oil pump assemblyAT- 2 8 2
10. 3rd one-way clutchAT- 2 8 4
11. Gear systemAT- 2 5 0
12. High and low reverse clutchAT- 2 9 6
13. Forward one- way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
AT- 1 7
, AT- 1 8 .) AT- 2 6 4
14. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to
AT- 1 7
, AT- 1 8
.) AT- 2 6 4
33When you press the
accelerator pedal and
shift speed D3
→ D2
the engine idles or the
transmission slips. ON vehicle
1. Fluid level and state
AT- 5 1
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT- 1 3 2
3. ATF pressure switch 6, high and low reverse clutch sole-
noid valve AT- 1 6 5,
AT- 1 5 1
4. ATF pressure switch 5 and direct clutch solenoid valve AT- 1 6 3,
AT- 1 4 7
5. CAN communication line AT- 9 6
6. Line pressure testAT- 5 2
7. Control valve with TCMAT- 2 3 0
OFF vehicle8. Torque converter
AT- 2 6 4
9. Oil pump assemblyAT- 2 8 2
10. 3rd one-way clutchAT- 2 8 4
11. Gear systemAT- 2 5 0
12. Direct clutchAT- 2 9 8
13. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 7
, AT- 1 8
.) AT- 2 6 4
No. Items
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TROUBLE DIAGNOSISAT-73
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Revision: November 2009 2006 QX56
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Slips/Will
Not
Engage When you press the
accelerator pedal and
shift speed D2 →
D1
the engine idles or the
transmission slips. ON vehicle
1. Fluid level and state
AT- 5 1
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT-132
3. ATF pressure switch 5 and direct clutch solenoid valve AT-163,
AT-147
4. CAN communication line AT- 9 6
5. Line pressure testAT- 5 2
6. Control valve with TCMAT-230
OFF vehicle7. Torque converter
AT-264
8. Oil pump assemblyAT-282
9. 3rd one-way clutchAT-284
10. 1st one-way clutchAT-291
11. Gear systemAT-250
12. Reverse brakeAT-264
13. Forward one- way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
AT- 1 7
, AT- 1 8 .) AT-264
14. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 7
, AT- 1 8
.) AT-264
35With selector lever in
“
D ” position, accelera-
tion is extremely poor. ON vehicle
1. Fluid level and state
AT- 5 1
2. Line pressure testAT- 5 2
3. Accelerator pedal position sensorAT-124
4. CAN communication line AT- 9 6
5. PNP switchAT-105
6. Control cable adjustmentAT-227
7. Control valve with TCMAT-230
OFF vehicle8. Torque converter
AT-264
9. Oil pump assemblyAT-282
10. 1st one-way clutchAT-291
11. Gear systemAT-250
12. Reverse brakeAT-264
13. Forward one- way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
AT- 1 7
, AT- 1 8 .) AT-264
14. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 7
, AT- 1 8
.) AT-264
No. Items
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AT-80
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
56
Others Maximum speed low.
ON vehicle
1. Fluid level and state
AT- 5 1
2. Line pressure testAT- 5 2
3. Accelerator pedal position sensorAT- 1 2 4
4. CAN communication line AT- 9 6
5. Direct clutch solenoid valveAT- 1 4 7
6. Control valve with TCMAT- 2 3 0
OFF vehicle7. Torque converter
AT- 2 6 4
8. Oil pump assemblyAT- 2 8 2
9. Input clutchAT- 2 8 6
10. Gear systemAT- 2 5 0
11. High and low reverse clutchAT- 2 9 6
12. Direct clutchAT- 2 9 8
13. Forward one- way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
AT- 1 7
, AT- 1 8 .) AT- 2 6 4
14 Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to
AT- 1 7
, AT- 1 8
.) AT- 2 6 4
57
Extremely large
creep. ON vehicle1. Engine idle speed
EC-76

2. CAN communication line AT- 9 6
3. ATF pressure switch 5AT- 1 6 3
OFF vehicle 4. Torque converter AT- 2 6 4
58With selector lever in
“
P ” position, vehicle
does not enter parking
condition or, with
selector lever in
another position, park-
ing condition is not
cancelled.
Refer to AT-180, "
In
“P” Position, Vehicle
Moves When Pushed"
. ON vehicle
1. PNP switch
AT- 1 0 5
2. Control cable adjustmentAT- 2 2 7
OFF vehicle 3. Parking pawl components AT- 2 5 0
59Vehicle runs with
transmission in
“P ”
position. ON vehicle1. PNP switch
AT- 1 0 5
2. Fluid level and state AT- 5 1
3. Control cable adjustmentAT- 2 2 7
4. Control valve with TCMAT- 2 3 0
5. Parking pawl componentsAT- 2 5 0
OFF vehicle 6. Gear system AT- 2 5 0
No. ItemsSymptom Condition Diagnostic ItemReference
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TROUBLE DIAGNOSISAT-81
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Others Vehicle runs with
transmission in
“N ”
position.
Refer to AT-181, "In
“N” Position, Vehicle
Moves" . ON vehicle
1. PNP switch
AT-105
2. Fluid level and state AT- 5 1
3. Control cable adjustmentAT-227
4. Control valve with TCMAT-230
OFF vehicle5. Input clutch
AT-286
6. Gear systemAT-250
7. Direct clutchAT-298
8. Reverse brakeAT-264
9. Forward one- way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
AT- 1 7
, AT- 1 8 .) AT-264
10. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 7
, AT- 1 8
.) AT-264
61Engine does not start
in
“N ” or “P ” position.
Refer to AT-179, "Engine Cannot Be
Started In “P” or “N”
Position" . ON vehicle
1. Ignition switch and starter
PG-4
, SC-
10
2. Control cable adjustment
AT-227
3. PNP switchAT-105
62Engine starts in posi-
tions other than “
N” or
“ P ”. ON vehicle1. Ignition switch and starter
PG-4
, SC-
10
2. Control cable adjustment
AT-227
3. PNP switchAT-105
63Engine stall. ON vehicle1. Fluid level and state
AT- 5 1
2. Engine speed signalAT- 11 6
3. Turbine revolution sensorAT-109
4. Torque converter clutch solenoid valve AT- 11 8
5. CAN communication line AT- 9 6
6. Control valve with TCMAT-230
OFF vehicle 7. Torque converter AT-264
64Engine stalls when
select lever shifted
“N ”
→ “ D ”, “ R”. ON vehicle1. Fluid level and state
AT- 5 1
2. Engine speed signalAT- 11 6
3. Turbine revolution sensorAT-109
4. Torque converter clutch solenoid valve AT- 11 8
5. CAN communication line AT- 9 6
6. Control valve with TCMAT-230
OFF vehicle 7. Torque converter AT-264
No. ItemsSymptom Condition Diagnostic ItemReference
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