2006 INFINITI QX56 automatic transmission

AT-20
A/T CONTROL SYSTEM
Revision: November 20092006 QX56
CLUTCH AND BAND CHART

—Operates

—Operates during “progressive ” acceleration.

—Operates and effects power transmission while coasting.

—Line pressure is applied but does not affect power transmission.

—Operates under conditions shown in HLR/C Operating Condition

— Operates under conditions shown in LC/B Operating Condition. Delay control is applied during D (4,3,2,1)
N shift.
Shift position I/C HLR/C D/C R/B FR/B LC/B Fwd/B
1st
OWC Fwd
OWC 3rd
OWC Remarks
P PARK POSITION
R REVERSE
POSITION
N NEUTRAL POSI-
TION
D 1st
Automatic shift
1 ⇔ 2⇔ 3⇔ 4⇔ 5
2nd
3rd4th
5th
1st
4 2nd
Automatic shift
3rd 1
⇔ 2⇔ 3⇔ 4
4th
3 1st
Automatic shift1⇔ 2⇔ 3⇐ 4
2nd
3rd 4th
2 1st
Automatic shift1⇔ 2⇐ 3⇐ 4
2nd
3rd4th
1 1st
Locks (held sta-tionary in 1st
gear)
1 ⇐ 2⇐ 3⇐ 4
2nd
3rd
4th

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

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

DTC P0717 TURBINE REVOLUTION SENSORAT-109
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Revision: November 2009 2006 QX56
DTC P0717 TURBINE REVOLUTION SENSORPFP:31935
DescriptionECS00CGT
The turbine revolution sensor detects input shaft rpm (revolutions per minute). It is located on the input side of
the automatic transmission. Monitors revolution of sensor 1 and sensor 2 for non-standard conditions.
CONSULT-II Reference ValueECS00CGU
On Board Diagnosis LogicECS00CGV

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “P0717 TURBINE REV S/CIRC” with CONSULT-II is detected under the following
conditions.
–When TCM does not receive the proper voltage signal from the sensor.
–When TCM detects an irregularity only at position of 4th gear for turbine revolution sensor 2.
Possible CauseECS00CGW

Harness or connectors
(The sensor circuit is open or shorted.)

Turbine revolution sensor 1, 2
DTC Confirmation ProcedureECS00CGX
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously performed, always turn ignition switch “OFF”
and wait at least 10 seconds before performing the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
WITH CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR ” mode for “A/T” with CONSULT-II.
3. Start engine and maintain the following conditions for at least 5 consecutive seconds.
VHCL SPEED SE: 40 km/h (25 MPH) or more
ENGINE SPEED: 1,500 rpm or more
ACCELE POS: 0.5/8 or more
Selector lever: “D” position
Gear position (Turbine revolution sensor 1): 4th or 5th posi-
tion
Gear position (Turbine revolution sensor 2): All position
Driving location: Driving the vehicle uphill (increased
engine load) will help maintain the driving conditions required for this test.
4. If DTC is detected, go to AT- 11 0 , "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (rpm)
TURBINE REV During driving (lock-up ON) Approximately matches the engine speed.
BCIA0030E

TROUBLE DIAGNOSIS FOR SYMPTOMSAT-181
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Revision: November 2009 2006 QX56
3. CHECK A/T FLUID CONDITION
1. Remove oil pan. Refer to AT- 2 3 0 , "
Control Valve With TCM and A/T Fluid Temperature Sensor 2" .
2. Check A/T fluid condition. Refer to AT- 1 2 , "
Checking Automatic
Transmission Fluid (ATF)" .
OK or NG
OK >> INSPECTION END
NG >> GO TO 4.
4. DETECT MALFUNCTIONING ITEM

Check the malfunction items. If any items are damaged, repair or replace damaged parts. Refer to AT- 6 1 ,
"Symptom Chart" (Symptom No.58).
OK or NG
OK >> INSPECTION END
NG >> Repair or replace damaged parts.
In “N” Position, Vehicle MovesECS00CK6
SYMPTOM:
Vehicle moves forward or backward when selecting “N” position.
DIAGNOSTIC PROCEDURE
1. CHECK PNP SWITCH CIRCUIT
Perform self-diagnosis. Refer to AT- 8 6 , "
SELF-DIAGNOSTIC RESULT MODE" .
Do the self-diagnostic results indicate PNP switch?
YES >> Check the malfunctioning system. Refer to AT- 1 0 5 , "DTC P0705 PARK/NEUTRAL POSITION
SWITCH" .
NO >> GO TO 2.
2. CHECK CONTROL CABLE
Check the control cable.

Refer to AT- 2 2 7 , "Checking of A/T Position" .
OK or NG
OK >> GO TO 3.
NG >> Adjust control cable. Refer to AT- 2 2 7 , "
Adjustment of A/
T Position" .
SCIA5199E
LCIA0345E

AT-182
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: November 20092006 QX56
3. CHECK A/T FLUID LEVEL
Check A/T fluid level. Refer to AT- 1 2 , "
Checking Automatic Trans-
mission Fluid (ATF)" .
OK or NG
OK >> GO TO 4.
NG >> Refill ATF.
4. CHECK A/T FLUID CONDITION
1. Remove oil pan. Refer to AT- 2 3 0 , "
Control Valve With TCM and A/T Fluid Temperature Sensor 2" .
2. Check A/T fluid condition. Refer to AT- 1 2 , "
Checking Automatic
Transmission Fluid (ATF)" .
OK or NG
OK >> GO TO 5.
NG >> Check the malfunction items. If any items are damaged, repair or replace damaged parts. Refer to AT- 6 1 , "
Symp-
tom Chart" (Symptom No.60).
5. CHECK SYMPTOM
Check again. Refer to AT- 5 5 , "
Check at Idle" .
OK or NG
OK >> INSPECTION END
NG >> GO TO 6.
6. PERFORM TCM INSPECTION
1. Perform TCM input/output signals inspection. Refer to AT- 8 3 , "
TCM Input/Output Signal Reference Val-
ues" .
2. If NG, recheck A/T assembly harness connector terminals for damage or loose connection with harness connector.
OK or NG
OK >> INSPECTION END
NG >> Repair or replace damaged parts.
Large Shock (“N” to “D” Position)ECS00CK7
SYMPTOM:
A noticeable shock occurs when the selector lever is shifted from the “N” to “D” position.
DIAGNOSTIC PROCEDURE
1. CHECK SELF-DIAGNOSTIC RESULTS
Perform self-diagnosis. Refer to AT- 8 6 , "
SELF-DIAGNOSTIC RESULT MODE" .
Do the self-diagnostic results indicate A/T fluid temperature sensor, engine speed signal, accelerator pedal
position sensor, ATF pressure switch 1, front brake solenoid valve, CAN communication line?
YES >> Check the malfunctioning system. Refer to AT- 1 2 7 , "DTC P1710 A/T FLUID TEMPERATURE
SENSOR CIRCUIT" , AT- 11 6 , "DTC P0725 ENGINE SPEED SIGNAL" ., AT- 1 2 4 , "DTC P1705
SAT638A
SCIA5199E

TROUBLE DIAGNOSIS FOR SYMPTOMSAT-183
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Revision: November 2009 2006 QX56
THROTTLE POSITION SENSOR" , AT- 1 5 9 , "DTC P1841 ATF PRESSURE SWITCH 1" , AT- 1 4 3 ,
"DTC P1757 FRONT BRAKE SOLENOID VALVE" , AT- 9 6 , "DTC U1000 CAN COMMUNICATION
LINE" .
NO >> GO TO 2.
2. ENGINE IDLE SPEED
Check the engine idle speed. Refer to EC-76, "
Idle Speed and Ignition Timing Check" .
OK or NG
OK >> GO TO 3.
NG >> Repair.
3. CHECK CONTROL CABLE
Check the control cable.

Refer to AT- 2 2 7 , "Checking of A/T Position" .
OK or NG
OK >> GO TO 4.
NG >> Adjust control cable. Refer to AT- 2 2 7 , "
Adjustment of A/
T Position" .
4. CHECK A/T FLUID LEVEL
Check the A/T fluid level. Refer to AT- 1 2 , "
Checking Automatic
Transmission Fluid (ATF)" .
OK or NG
OK >> GO TO 5.
NG >> Refill ATF.
5. CHECK LINE PRESSURE
Check line pressure at idle with selector lever in “D” position. Refer
to AT- 5 2 , "
LINE PRESSURE TEST" .
OK or NG
OK >> GO TO 8.
NG - 1 >> Line pressure high: GO TO 6.
NG - 2 >> Line pressure low: GO TO 7.
LCIA0345E
SAT638A
SAT494G

AT-184
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: November 20092006 QX56
6. DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT- 2 3 0 , "
Control Valve With TCM and A/T Fluid Temperature Sen-
sor 2" .
2. Disassemble A/T. Refer to AT- 2 6 4 , "
Disassembly" .
3. Check the following items:
–Oil pump assembly. Refer to AT- 2 8 2 , "Oil Pump" .
OK or NG
OK >> GO TO 8.
NG >> Repair or replace damaged parts.
7. DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT- 2 3 0 , "
Control Valve With TCM and A/T Fluid Temperature Sen-
sor 2" .
2. Disassemble A/T. Refer to AT- 2 6 4 , "
Disassembly" .
3. Check the following items:
–Oil pump assembly. Refer to AT- 2 8 2 , "Oil Pump" .
–Power train system. Refer to AT- 2 6 4 , "Disassembly" .
–Transmission case. Refer to AT- 2 6 4 , "Disassembly" .
OK or NG
OK >> GO TO 8.
NG >> Repair or replace damaged parts.
8. CHECK A/T FLUID CONDITION
1. Remove oil pan. Refer to AT- 2 3 0 , "
Control Valve With TCM and A/T Fluid Temperature Sensor 2" .
2. Check A/T fluid condition. Refer to AT- 1 2 , "
Checking Automatic
Transmission Fluid (ATF)" .
OK or NG
OK >> GO TO 10.
NG >> GO TO 9.
9. DETECT MALFUNCTIONING ITEM

Check the malfunction items. If any items are damaged, repair or replace damaged parts. Refer to AT- 6 1 ,
"Symptom Chart" (Symptom No.1).
OK or NG
OK >> GO TO 10.
NG >> Repair or replace damaged parts.
10. CHECK SYMPTOM
Check again. Refer to AT- 5 5 , "
Check at Idle" .
OK or NG
OK >> INSPECTION END
NG >> GO TO 11.
SCIA5199E