2004 INFINITI QX56 transmission

AT-44
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
A/T Interlock

If there is an A/T interlock judgment malfunction, the transmission is fixed in 2nd gear to make driving pos-
sible.
NOTE:
When the vehicle is driven fixed in 2nd gear, a turbine revolution sensor malfunction is displayed,
but this is not a turbine revolution sensor malfunction.

When the coupling pattern below is detected, the fail-safe action corresponding to the pattern is per-
formed.
A/T INTERLOCK COUPLING PATTERN TABLE

: NG X: OK
A/T 1st Engine Braking

When there is an A/T first gear engine brake judgment malfunction, the low coast brake solenoid is
switched “OFF” to avoid the engine brake operation.
Line Pressure Solenoid

The solenoid is switched “OFF” and the line pressure is set to the maximum hydraulic pressure to make
driving possible.
Torque Converter Clutch Solenoid

The solenoid is switched “OFF” to release the lock-up.
Low Coast Brake Solenoid

When a (electrical or functional) malfunction occurs, in order to make driving possible, the engine brake is
not applied in 1st and 2nd gear.
Input Clutch Solenoid

If a (electrical or functional) malfunction occurs with the solenoid either “ON” or “OFF”, the transmission is
held in 4th gear to make driving possible.
Direct Clutch Solenoid

If a (electrical or functional) malfunction occurs with the solenoid either “ON” or “OFF”, the transmission is
held in 4th gear to make driving possible.
Front Brake Solenoid

If a (electrical or functional) malfunction occurs with the solenoid “ON”, in order to make driving possible,
the A/T is held in 5th gear; if the solenoid is OFF, 4th gear.
High and Low Reverse Clutch Solenoid

If a (electrical or functional) malfunction occurs with the solenoid either “ON” or “OFF”, the transmission is
held in 4th gear to make driving possible.
Turbine Revolution Sensor 1 or 2

The control is the same as if there were no turbine revolution sensors, 5th gear is prohibited.
Gear positionATF pressure switch output
Fail-safe
functionClutch pressure output pattern after fail-safe func-
tion
SW3
(I/C)SW6
(HLR/
C)SW5
(D/C)SW1
(Fr/B)SW2
(LC/B)I/C HLR/C D/C Fr/B LC/B L/U
A/T inter-
lock cou-
pling pattern3rd – X X –
Held in
2nd gearOFF OFF ON OFF OFF OFF
4th – X X –
Held in
2nd gearOFF OFF ON OFF OFF OFF
5th X X – X
Held in
2nd gearOFF OFF ON OFF OFF OFF

AT-48
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
4❏ Perform all road tests and enter checks in required inspection items.AT-6 1
4-1.Check before engine is started
AT-6 2
❏ AT-191, "AT CHECK Indicator Lamp Does Not Come On" .
❏ Perform self-diagnostics Enter checks for detected items. AT- 9 3
❏ AT- 1 0 3 , "DTC U1000 CAN COMMUNICATION LINE"
❏ AT- 1 0 5 , "DTC P0615 START SIGNAL CIRCUIT"
❏ AT- 1 0 8 , "DTC P0700 TCM"
❏ AT- 1 0 9 , "DTC P0705 PARK/NEUTRAL POSITION SWITCH"
❏ AT- 11 2 , "DTC P0720 VEHICLE SPEED SENSOR A/T (REVOLUTION SENSOR)"
❏ AT- 11 5 , "DTC P0725 ENGINE SPEED SIGNAL"
❏ AT- 11 8 , "DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE"
❏ AT- 1 2 1 , "DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)"
❏ AT- 1 2 4 , "DTC P0745 LINE PRESSURE SOLENOID VALVE"
❏ AT- 1 2 7 , "DTC P1702 TRANSMISSION CONTROL MODULE (RAM)"
❏ AT- 1 2 8 , "DTC P1703 TRANSMISSION CONTROL MODULE (ROM)"
❏ AT- 1 2 9 , "DTC P1705 THROTTLE POSITION SENSOR"
❏ AT- 1 3 1 , "DTC P1710 A/T FLUID TEMPERATURE SENSOR CIRCUIT"
❏ AT- 1 3 4 , "DTC P1716 TURBINE REVOLUTION SENSOR"
❏ AT- 1 3 6 , "DTC P1721 VEHICLE SPEED SENSOR MTR"
❏ AT- 1 3 9 , "DTC P1730 A/T INTERLOCK"
❏ AT- 1 4 2 , "DTC P1731 A/T 1ST ENGINE BRAKING"
❏ AT- 1 4 5 , "DTC P1752 INPUT CLUTCH SOLENOID VALVE"
❏ AT- 1 4 8 , "DTC P1754 INPUT CLUTCH SOLENOID VALVE FUNCTION"
❏ AT- 1 5 1 , "DTC P1757 FRONT BRAKE SOLENOID VALVE"
❏ AT- 1 5 4 , "DTC P1759 FRONT BRAKE SOLENOID VALVE FUNCTION"
❏ AT- 1 5 7 , "DTC P1762 DIRECT CLUTCH SOLENOID VALVE"
❏ AT- 1 6 0 , "DTC P1764 DIRECT CLUTCH SOLENOID VALVE FUNCTION"
❏ AT- 1 6 3 , "DTC P1767 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE"
❏ AT- 1 6 6 , "DTC P1769 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE
FUNCTION"
❏ AT- 1 6 9 , "DTC P1772 LOW COAST BRAKE SOLENOID VALVE"
❏ AT- 1 7 2 , "DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION"
❏ AT- 1 7 5 , "DTC P1841 ATF PRESSURE SWITCH 1"
❏ AT- 1 7 8 , "DTC P1843 ATF PRESSURE SWITCH 3"
❏ AT- 1 8 1 , "DTC P1845 ATF PRESSURE SWITCH 5"
❏ AT- 1 8 4 , "DTC P1846 ATF PRESSURE SWITCH 6"
4-2.Idle inspection
AT-6 2
❏ AT-192, "Engine Cannot Be Started In “P” or “N” Position"
❏ AT-193, "In “P” Position, Vehicle Moves When Pushed"
❏ AT-194, "In “N” Position, Vehicle Moves"
❏ AT-195, "Large Shock (“N” to “D” Position)"
❏ AT-198, "Vehicle Does Not Creep Backward In “R” Position"
❏ AT-201, "Vehicle Does Not Creep Forward In “D” Position"
4-3.Driving tests
AT-6 3
Part 1
❏ AT-203, "
Vehicle Cannot Be Started From D1"
❏ AT-206, "A/T Does Not Shift: D1 → D2"
❏ AT-208, "A/T Does Not Shift: D2 → D3"
❏ AT-210, "A/T Does Not Shift: D3 → D4"
❏ AT-213, "A/T Does Not Shift: D4 → D5"
❏ AT-215, "A/T Does Not Perform Lock-up"
❏ AT-217, "A/T Does Not Hold Lock-up Condition"
❏ AT-219, "Lock-up Is Not Released"
❏ AT-220, "Engine Speed Does Not Return to Idle"

TROUBLE DIAGNOSIS
AT-49
D
E
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MA
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AT
Revision: August 20072004 QX56
44-3Part 2
AT- 6 5
❏ AT-203, "Vehicle Cannot Be Started From D1"
❏ AT-206, "A/T Does Not Shift: D1 → D2"
❏ AT-208, "A/T Does Not Shift: D2 → D3"
❏ AT-210, "A/T Does Not Shift: D3 → D4"
Part 3
AT- 6 6
❏ AT-221, "A/T Does Not Shift: 5th gear → 4th gear"
❏ AT-224, "A/T Does Not Shift: 4th gear → 3rd gear"
❏ AT-225, "A/T Does Not Shift: 3rd gear → 2nd gear"
❏ AT-227, "A/T Does Not Shift: 2nd gear → 1st gear"
❏ AT-230, "Vehicle Does Not Decelerate By Engine Brake"
❏ Perform self-diagnostics Enter checks for detected items. AT- 9 3
❏ AT-103, "DTC U1000 CAN COMMUNICATION LINE"
❏ AT-105, "DTC P0615 START SIGNAL CIRCUIT"
❏ AT-108, "DTC P0700 TCM"
❏ AT-109, "DTC P0705 PARK/NEUTRAL POSITION SWITCH"
❏ AT-112, "DTC P0720 VEHICLE SPEED SENSOR A/T (REVOLUTION SENSOR)"
❏ AT-115, "DTC P0725 ENGINE SPEED SIGNAL"
❏ AT-118, "DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE"
❏ AT-121, "DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)"
❏ AT-124, "DTC P0745 LINE PRESSURE SOLENOID VALVE"
❏ AT-127, "DTC P1702 TRANSMISSION CONTROL MODULE (RAM)"
❏ AT-128, "DTC P1703 TRANSMISSION CONTROL MODULE (ROM)"
❏ AT-129, "DTC P1705 THROTTLE POSITION SENSOR"
❏ AT-131, "DTC P1710 A/T FLUID TEMPERATURE SENSOR CIRCUIT"
❏ AT-134, "DTC P1716 TURBINE REVOLUTION SENSOR"
❏ AT-136, "DTC P1721 VEHICLE SPEED SENSOR MTR"
❏ AT-139, "DTC P1730 A/T INTERLOCK"
❏ AT-142, "DTC P1731 A/T 1ST ENGINE BRAKING"
❏ AT-145, "DTC P1752 INPUT CLUTCH SOLENOID VALVE"
❏ AT-148, "DTC P1754 INPUT CLUTCH SOLENOID VALVE FUNCTION"
❏ AT-151, "DTC P1757 FRONT BRAKE SOLENOID VALVE"
❏ AT-154, "DTC P1759 FRONT BRAKE SOLENOID VALVE FUNCTION"
❏ AT-157, "DTC P1762 DIRECT CLUTCH SOLENOID VALVE"
❏ AT-160, "DTC P1764 DIRECT CLUTCH SOLENOID VALVE FUNCTION"
❏ AT-163, "DTC P1767 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE"
❏ AT-166, "DTC P1769 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE
FUNCTION"
❏ AT-169, "DTC P1772 LOW COAST BRAKE SOLENOID VALVE"
❏ AT-172, "DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION"
❏ AT-175, "DTC P1841 ATF PRESSURE SWITCH 1"
❏ AT-178, "DTC P1843 ATF PRESSURE SWITCH 3"
❏ AT-181, "DTC P1845 ATF PRESSURE SWITCH 5"
❏ AT-184, "DTC P1846 ATF PRESSURE SWITCH 6"
5❏ Inspect each system for items found to be NG in the self-diagnostics and repair or replace the malfunction
parts.
6❏ Perform all road tests and enter the checks again for the required items.AT- 6 1
7❏ For any remaining NG items, perform the “diagnostics procedure” and repair or replace the malfunction parts.
See the chart for diagnostics by symptoms. (This chart also contains other symptoms and inspection proce-
dures.)AT- 6 8
8❏ Erase the results of the self-diagnostics from the TCM.AT- 4 0

TROUBLE DIAGNOSIS
AT-63
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AT
Revision: August 20072004 QX56
4. CHECK “N” POSITION FUNCTIONS
1. Start the engine.
2. Move selector lever to “N” position.
3. Release the parking brake.
Does vehicle move forward or backward?
YES >> Enter a check mark at “Vehicle moves in “N” position” on the diagnostics worksheet, then continue
the road test.
NO >> GO TO 5.
5. CHECK SHIFT SHOCK
1. Engage the brake.
2. Move selector lever to “D” position.
When the transmission is shifted from
“N” to “D”, is there an excessive shock?
YES >> Enter a check mark at “Large shock when shifted from N to D” on the diagnostics worksheet, then
continue the road test.
NO >> GO TO 6.
6. CHECK “R” POSITION FUNCTIONS
1. Engage the brake.
2. Move selector lever to “R” position.
3. Disengage the brake for 4 to 5 seconds.
Does the vehicle creep backward?
YES >> GO TO 7.
NO >> Enter a check mark at “Vehicle does not creep backward in R position” on the diagnostics work-
sheet, then continue the road test.
7. CHECK “D” POSITION FUNCTIONS
Inspect whether the vehicle moves forward when the transmission is put into the “D” position.
Does the vehicle creep forward in the
“D” positions?
YES >> Go to AT- 6 3 , "Cruise Test - Part 1" , AT- 6 5 , "Cruise Test - Part 2" , and AT- 6 6 , "Cruise Test - Part
3" .
NO >> Enter a check mark at “Vehicle does not move forward in D positions” on the diagnostics work-
sheet, then continue the road test.
Cruise Test - Part 1UCS002D0
1. CHECK STARTING OUT FROM D1
1. Drive the vehicle for about 10 minutes to warm up the engine oil and ATF.
Appropriate temperature for the ATF: 50 - 80°C (122 - 176°F)
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 off the gear positions.
Starts from D1?
YES >> GO TO 2.
NO >> Enter a check mark at “Vehicle cannot be started from D1” on the diagnostics worksheet, then
continue the road test.

AT-66
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
2. CHECK SHIFT-UP D1 → D2
Press the accelerator pedal down all the way and inspect whether or not the transmission shifts up (D1 → D2)
at the correct speed.

Refer to AT-67, "Vehicle Speed When Shifting Gears" .
With CONSULT-II
Read the gear position, throttle position and vehicle speed.
Does the A/T shift-up D1
→ D2 at the correct speed?
YES >> GO TO 3.
NO >> Enter a check mark at “Vehicle does not shift D1 → D2” on the diagnostics worksheet, then con-
tinue the road test.
3. CHECK SHIFT-UP D2 → D3
Press the accelerator pedal down all the way and inspect whether or not the transmission shifts up (D2 → D3)
at the correct speed.

Refer to AT-67, "Vehicle Speed When Shifting Gears" .
With CONSULT-II
Read the gear position, throttle position and vehicle speed.
Does the A/T shift-up D2
→ D3 at the correct speed?
YES >> GO TO 4.
NO >> Enter a check mark at “Vehicle does not shift D2 → D3” on the diagnostics worksheet, then con-
tinue the road test.
4. CHECK SHIFT-UP D3 → D4 AND ENGINE BRAKE
When the transmission changes speed D3 → D4, return the accelerator pedal.
Does the A/T shift-up D3
→ D4 and apply the engine brake?
YES >> 1. Stop the vehicle.
2. See AT-66, "
Cruise Test - Part 3" .
NO >> Enter a check mark at “Vehicle does not shift D3 → D4” on the diagnostics worksheet, then con-
tinue the road test.
Cruise Test - Part 3UCS002D2
1. CHECK SHIFT-DOWN
During D
5 driving, move gear selector from D → 4 → 3 → 2 → 1.
With CONSULT-II
Read the gear position.
Is downshifting correctly performed?
YES >> GO TO 2.
NO >> Enter a check mark at “Vehicle does not shift” at the corresponding position (5th → 4th, 4th → 3rd,
3rd → 2nd, 2nd → 1st) on the diagnostics worksheet, then continue the road test.
2. CHECK ENGINE BRAKE
Does engine braking effectively reduce speed in 1
1 position?
YES >> 1. Stop the vehicle.
2. Carry out the self-diagnostics. Refer to AT-93, "
SELF-DIAGNOSTIC RESULT MODE" .
NO >> Enter a check mark at “Vehicle does not decelerate by engine brake” on the diagnostics work-
sheet, then continue trouble diagnosis.

AT-78
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
30
Slips/Will
Not
engageNo shock at all or the
clutch slips when
vehicle changes
speed D
4 → D5 .ON vehicle1. Fluid level and stateAT-5 8
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 11 2,
AT- 1 3 6
3. ATF pressure switch 1 and front brake solenoid valveAT- 1 7 5,
AT- 1 5 1
4. ATF pressure switch 5 and direct clutch solenoid valveAT- 1 8 1,
AT- 1 5 7
5. CAN communication lineAT- 1 0 3
6. Line pressure testAT-5 9
7. Control valve with TCMAT- 2 4 1
OFF vehicle8. Torque converterAT- 2 7 3
9. Oil pump assemblyAT- 2 9 0
10. Front brake (brake band)AT- 2 7 3
11. Input clutchAT- 2 9 5
12. Gear systemAT- 2 6 1
13. High and low reverse clutchAT- 3 0 5
31When you press the
accelerator pedal and
shift speed D5 → D4
the engine idles or the
transmission slips.ON vehicle1. Fluid level and stateAT-5 8
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 11 2,
AT- 1 3 6
3. ATF pressure switch 1 and front brake solenoid valveAT- 1 7 5,
AT- 1 5 1
4. ATF pressure switch 5 and direct clutch solenoid valveAT- 1 8 1,
AT- 1 5 7
5. CAN communication lineAT- 1 0 3
6. Line pressure testAT-5 9
7. Control valve with TCMAT- 2 4 1
OFF vehicle8. Torque converterAT- 2 7 3
9. Oil pump assemblyAT- 2 9 0
10. Input clutchAT- 2 9 5
11. Gear systemAT- 2 6 1
12. High and low reverse clutchAT- 3 0 5
13. Direct clutchAT- 3 0 7
No. Items Symptom Condition Diagnostic ItemReference
page

TROUBLE DIAGNOSIS
AT-79
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AT
Revision: August 20072004 QX56
32
Slips/Will
Not
engageWhen you press the
accelerator pedal and
shift speed D4 → D3
the engine idles or the
transmission slips.ON vehicle1. Fluid level and stateAT- 5 8
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 11 2,
AT- 1 3 6
3. ATF pressure switch 3 and input clutch solenoid valveAT- 1 7 8,
AT- 1 4 5
4. ATF pressure switch 1 and front brake solenoid valveAT- 1 7 5,
AT- 1 5 1
5. CAN communication lineAT- 1 0 3
6. Line pressure testAT- 5 9
7. Control valve with TCMAT- 2 4 1
OFF vehicle8. Torque converter AT- 2 7 3
9. Oil pump assemblyAT- 2 9 0
10. 3rd one-way clutchAT- 2 9 2
11. Gear systemAT- 2 6 1
12. High and low reverse clutchAT- 3 0 5
13. Forward one- way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
AT- 1 8
, AT-1 9 .)AT- 2 7 3
14. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT-1 8
, AT - 1 9
.)AT- 2 7 3
33When you press the
accelerator pedal and
shift speed D3 → D2
the engine idles or the
transmission slips.ON vehicle1. Fluid level and stateAT- 5 8
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 11 2,
AT- 1 3 6
3. ATF pressure switch 6, high and low reverse clutch sole-
noid valveAT- 1 8 4,
AT- 1 6 3
4. ATF pressure switch 5 and direct clutch solenoid valveAT- 1 8 1,
AT- 1 5 7
5. CAN communication lineAT- 1 0 3
6. Line pressure testAT- 5 9
7. Control valve with TCMAT- 2 4 1
OFF vehicle8. Torque converterAT- 2 7 3
9. Oil pump assemblyAT- 2 9 0
10. 3rd one-way clutchAT- 2 9 2
11. Gear systemAT- 2 6 1
12. Direct clutchAT- 3 0 7
13. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT-1 8
, AT - 1 9
.)AT- 2 7 3
No. Items Symptom Condition Diagnostic ItemReference
page

AT-80
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
34
Slips/Will
Not
EngageWhen you press the
accelerator pedal and
shift speed D2 → D1
the engine idles or the
transmission slips.ON vehicle1. Fluid level and stateAT-5 8
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 11 2,
AT- 1 3 6
3. ATF pressure switch 5 and direct clutch solenoid valveAT- 1 8 1,
AT- 1 5 7
4. CAN communication lineAT- 1 0 3
5. Line pressure testAT-5 9
6. Control valve with TCMAT- 2 4 1
OFF vehicle7. Torque converterAT- 2 7 3
8. Oil pump assemblyAT- 2 9 0
9. 3rd one-way clutchAT- 2 9 2
10. 1st one-way clutchAT- 3 0 0
11. Gear systemAT- 2 6 1
12. Reverse brakeAT- 2 7 3
13. Forward one- way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
AT-1 8
, AT- 1 9 .)AT- 2 7 3
14. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 8
, AT- 1 9
.)AT- 2 7 3
35With selector lever in
“D” position, accelera-
tion is extremely poor.ON vehicle1. Fluid level and stateAT-5 8
2. Line pressure testAT-5 9
3. Accelerator pedal position sensorAT- 1 2 9
4. CAN communication lineAT- 1 0 3
5. PNP switchAT- 1 0 9
6. Control cable adjustmentAT- 2 3 4
7. Control valve with TCMAT- 2 4 1
OFF vehicle8. Torque converterAT- 2 7 3
9. Oil pump assemblyAT- 2 9 0
10. 1st one-way clutchAT- 3 0 0
11. Gear systemAT- 2 6 1
12. Reverse brakeAT- 2 7 3
13. Forward one- way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
AT-1 8
, AT- 1 9 .)AT- 2 7 3
14. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 8
, AT- 1 9
.)AT- 2 7 3
No. Items Symptom Condition Diagnostic ItemReference
page