2007 INFINITI QX56 ignition

AT-42
< SERVICE INFORMATION >
ON BOARD DIAGNOSTIC (OBD) SYSTEM
The MIL is located on the instrument panel.
1. The MIL will light up when the ignition switch is turned “ON” with-
out the engine running. This is a bulb check.
• If the MIL does not light up, refer to DI-26
.
2. When the engine is started, the MIL should go off.
If the MIL remains on, the on board diagnostic system has
detected an engine system malfunction.
SEF217U

TROUBLE DIAGNOSIS
AT-43
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TROUBLE DIAGNOSIS
DTC Inspection Priority ChartINFOID:0000000003532243
If some DTCs are displayed at the same time, perform inspections one by one based on the following priority
chart.
NOTE:
If DTC U1000 is displayed with other DTCs, first perform the trouble diagnosis for DTC U1000. Refer to
AT- 9 1
.
Fail-SafeINFOID:0000000003532244
The TCM has an electrical fail-safe mode. This mode makes it possible to operate even if there is an error in a
main electronic control input/output signal circuit. In fail-safe mode the transmission is fixed in 2nd, 4th or 5th
(depending on the breakdown position), so the customer should feel “slipping” or “poor acceleration”.
Even when the electronic circuits are normal, under special conditions (for example, when slamming on the
brake with the wheels spinning drastically and stopping the tire rotation), the transmission can go into fail-safe
mode. If this happens, switch “OFF” the ignition switch for 10 seconds, then switch it “ON” again to return to
the normal shift pattern. Therefore, the customer's vehicle has returned to normal, so handle according to the
“diagnostics flow” (Refer to AT-44, "
How To Perform Trouble Diagnosis for Quick and Accurate Repair").
FAIL-SAFE FUNCTION
If any malfunction occurs in a sensor or solenoid, this function controls the A/T to mark driving possible.
Vehicle Speed Sensor
• Signals are input from two systems - from vehicle speed sensor A/T (revolution sensor) installed on the
transmission and from combination meter so normal driving is possible even if there is a malfunction in one
of the systems. And if vehicle speed sensor A/T (revolution sensor) has unusual cases, 5th gear is prohib-
ited.
Accelerator Pedal Position Sensor
• If there is a malfunction in one of the systems, the accelerator opening angle is controlled by ECM according
to a pre-determined accelerator angle to make driving possible. And if there are malfunctions in tow sys-
tems, the engine speed is fixed by ECM to a pre-determined engine speed to make driving possible.
Throttle Position Sensor
• If there is a malfunction in one of the systems, the accelerator opening angle is controlled by ECM according
to a pre-determined accelerator angle to make driving possible. And if there are malfunctions in tow sys-
tems, the accelerator opening angle is controlled by the idle signal sent from the ECM which is based on
input indicating either idle condition or off-idle condition (pre-determined accelerator opening) in order to
make driving possible.
PNP Switch
• In the unlikely event that a malfunction signal enters the TCM, the position indicator is switched “OFF”, the
starter relay is switched “OFF” (starter starting is disabled), the back-up lamp relay switched “OFF” (back-up
lamp is OFF) and the position is fixed to the “D” range to make driving possible.
Starter Relay
• The starter relay is switched “OFF”. (Starter starting is disabled.)
A/T Interlock
• If there is an A/T interlock judgment malfunction, the transmission is fixed in 2nd gear to make driving possi-
ble.
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 performed.
A/T INTERLOCK COUPLING PATTERN TABLE
Priority Detected items (DTC)
1 U1000 CAN communication line
2 Except above

TROUBLE DIAGNOSIS
AT-55
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ROAD TEST
Description
• The road test inspects overall performance of the A/T and analyzes possible malfunction causes.
• The road test is carried out in the following three stages.
1. Check before engine is started. Refer to AT- 5 5
.
2. Check at idle. Refer to AT- 5 5
3. Cruise test
• Inspect all the items from Part 1 to Part 3. Refer to AT- 5 6
, AT- 5 8, AT- 5 9.
• Before beginning the road test, check the test procedure and inspection items.
• Test all inspection items until the symptom is uncovered. Diagnose NG items when all road tests are com-
plete.
Check Before Engine Is StartedINFOID:0000000003532249
1.CHECK AT CHECK INDICATOR LAMP
1. Park vehicle on level surface.
2. Move selector lever to “P” position.
3. Turn ignition switch to “OFF” position and wait at least 10 seconds.
4. Turn ignition switch to “ON” position. (Do not start engine.)
Does AT CHECK indicator lamp light up for about 2 seconds?
YES >> 1. Turn ignition switch to “OFF” position.
2. Carry out the self-diagnostics and record all NG items on the diagnostics worksheet. Refer to
AT-83, "
CONSULT-II Function (A/T)".
3. Go to AT-55, "
Check at Idle".
NO >> Stop the road test and go to AT-167, "
A/T Check Indicator Lamp Does Not Come On".
Check at IdleINFOID:0000000003532250
1.CHECK STARTING THE ENGINE
1. Park vehicle on level surface.
2. Move selector lever to “P” or “N” position.
3. Turn ignition switch to “OFF” position.
4. Turn ignition switch to “START” position.
Does the engine start?
YES >> GO TO 2.
NO >> Stop the road test and go to AT-168, "
Engine Cannot Be Started in "P" or "N" Position".
2.CHECK STARTING THE ENGINE
1. Turn ignition switch to “ON” position.
2. Move selector lever in “D”,“4”, “3”, “2”, “1” or “R” position.
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 standard posi-
tion.Possible causes include malfunctions in the pressure supply system and malfunction in the pres-
sure 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 spe-
cific 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. Judgement Possible cause

AT-56
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
3. Turn ignition switch to “START” position.
Does the engine start in either position?
YES >> Stop the road test and go to AT-168, "Engine Cannot Be Started in "P" or "N" Position".
NO >> GO TO 3.
3.CHECK “P” POSITION FUNCTIONS
1. Move selector lever to “P” position.
2. Turn ignition switch to “OFF” position.
3. Release the parking brake.
4. Push the vehicle forward or backward.
5. Engage the parking brake.
When you push the vehicle with disengaging the parking brake, does it move?
YES >> Enter a check mark at “In “P” Position Vehicle Moves When Pushed” on the diagnostics work-
sheet, then continue the road test.
NO >> GO TO 4.
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 “In “N” Position Vehicle Moves” on the diagnostics worksheet, then con-
tinue 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 ("N" to "D" Position) on the diagnostics worksheet, then con-
tinue the road test.
NO >> GO TO 6.
6.CHECK “R” POSITION FUNCTIONS
1. Engage the brake.
2. Move selector lever to “R” position.
3. Release 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
worksheet, then continue the road test.
7.CHECK “D” POSITION FUNCTIONS
Inspect whether the vehicle creeps forward when the transmission is put into the “D” position.
Does the vehicle creep forward in the
“D” positions?
YES >> Go to AT-56, "Cruise Test - Part 1", AT-58, "Cruise Test - Part 2", and AT-59, "Cruise Test - Part 3".
NO >> Enter a check mark at “Vehicle Does Not Creep Forward in "D" Position” on the diagnostics work-
sheet, then continue the road test.
Cruise Test - Part 1INFOID:0000000003532251
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.

TROUBLE DIAGNOSIS
AT-81
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60
OthersVehicle runs with
transmission in “N” po-
sition.
Refer to AT- 1 6 9 , "In
"N" Position, Vehicle
Moves".ON vehicle1. PNP switchAT- 9 9
2. Fluid level and stateAT- 5 1
3. Control cable adjustmentAT-208
4. Control valve with TCMAT-210
OFF vehicle5. Input clutchAT-262
6. Gear systemAT-228
7. Direct clutchAT-274
8. Reverse brakeAT-240
9. Forward one- way clutch (Parts behind drum support is im-
possible to perform inspection by disassembly. Refer to AT-
19, AT- 2 0.)AT-240
10. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 9
, AT- 2 0.)AT-240
61Engine does not start
in “N” or “P” position.
Refer to AT- 1 6 8 , "En-
gine Cannot Be Start-
ed in "P" or "N"
Position".ON vehicle1. Ignition switch and starterPG-3
, SC-
9
2. Control cable adjustmentAT-208
3. PNP switchAT- 9 9
62Engine starts in posi-
tions other than “N” or
“P”.ON vehicle1. Ignition switch and starterPG-3
, SC-
9
2. Control cable adjustmentAT-208
3. PNP switchAT- 9 9
63 Engine stall.ON vehicle1. Fluid level and stateAT- 5 1
2. Engine speed signalAT-109
3. Turbine revolution sensorAT-103
4. Torque converter clutch solenoid valveAT- 111
5. CAN communication lineAT- 9 1
6. Control valve with TCMAT-210
OFF vehicle 7. Torque converterAT-240
64Engine stalls when se-
lect lever shifted “N” →
“D”, “R”.ON vehicle1. Fluid level and stateAT- 5 1
2. Engine speed signalAT-109
3. Turbine revolution sensorAT-103
4. Torque converter clutch solenoid valveAT- 111
5. CAN communication lineAT- 9 1
6. Control valve with TCMAT-210
OFF vehicle 7. Torque converterAT-240
No. Items Symptom Condition Diagnostic ItemReference
page

TROUBLE DIAGNOSIS
AT-85
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X: Applicable, —: Not applicable
Items (CONSULT-II
screen terms)Malfunction is detected when...TCM self-di-
agnosisOBD-II (DTC)
“A/T” with
CONSULT-IIMIL indicator
lamp*1, “EN-
GINE” with
CONSULT-II or
GST
CAN COMM CIRCUIT • When a malfunction is detected in CAN communications U1000 U1000
STARTER RELAY/
CIRC• If this signal is ON other than in P or N position, this is judged to be a
malfunction.
(And if it is OFF in P or N position, this too is judged to be a malfunction.)P0615 —
TCM • TCM is malfunctioning. P0700 P0700
PNP SW/CIRC• PNP switch 1-4 signals input with impossible pattern
• “P” position is detected from N position without any other position being
detected in between.P0705 P0705
TURBINE REV S/CIRC• TCM does not receive the proper voltage signal from the sensor.
• TCM detects an irregularity only at position of 4th gear for turbine revo-
lution sensor 2.P0717 P0717
VEH SPD SEN/CIR AT
(Revolution sensor)• Signal from vehicle speed sensor A/T (Revolution sensor) not input due
to cut line or the like
• Unexpected signal input during running
• After ignition switch is turned ON, unexpected signal input from vehicle
speed sensor MTR before the vehicle starts movingP0720 P0720
ENGINE SPEED SIG • TCM does not receive the CAN communication signal from the ECM. P0725 —
TCC SOLENOID/CIRC • Normal voltage not applied to solenoid due to cut line, short, or the like P0740 P0740
A/T TCC S/V FNCTN• A/T cannot perform lock-up even if electrical circuit is good.
• TCM detects as irregular by comparing difference value with slip rota-
tion.P0744 P0744*2
L/PRESS SOL/CIRC• Normal voltage not applied to solenoid due to cut line, short, or the like
• TCM detects as irregular by comparing target value with monitor value.P0745 P0745
TP SEN/CIRC A/T• TCM does not receive the proper accelerator pedal position signals (in-
put by CAN communication) from ECM.P1705 P1705
ATF TEMP SEN/CIRC• During running, the ATF temperature sensor signal voltage is exces-
sively high or lowP1710 P0710
VEH SPD SE/CIR·MTR• Signal (CAN communication) from vehicle speed sensor MTR not input
due to cut line or the like
• Unexpected signal input during runningP1721 —
A/T INTERLOCK• Except during shift change, the gear position and ATF pressure switch
states are monitored and comparative judgement made.P1730 P1730
A/T 1ST E/BRAKING• Each ATF pressure switch and solenoid current is monitored and if a
pattern is detected having engine braking 1st gear other than in the "1"
position, a malfunction is detected.P1731 —
I/C SOLENOID/CIRC• Normal voltage not applied to solenoid due to functional malfunction,
cut line, short, or the like
• TCM detects as irregular by comparing target value with monitor value.P1752 P1752
I/C SOLENOID FNCTN • TCM detects that actual gear ratio is irregular, and relation between
gear position and condition of ATF pressure switch 3 is irregular during
depressing accelerator pedal. (Other than during shift change)
• TCM detects that relation between gear position and condition of ATF
pressure switch 3 is irregular during releasing accelerator pedal. (Other
than during shift change)P1754 P1754*2
FR/B SOLENOID/CIRC• Normal voltage not applied to solenoid due to functional malfunction,
cut line, short, or the like
• TCM detects as irregular by comparing target value with monitor value.P1757 P1757

DTC U1000 CAN COMMUNICATION LINE
AT-91
< SERVICE INFORMATION >
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DTC U1000 CAN COMMUNICATION LINE
DescriptionINFOID:0000000003532260
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 malfunction detection ability.
Many electronic 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 con-
nected 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.
On Board Diagnosis LogicINFOID:0000000003532261
• This is an OBD-II self-diagnostic item.
• Diagnostic trouble code “U1000 CAN COMM CIRCUIT” with CONSULT-II is detected when TCM cannot
communicate to other control units.
Possible CauseINFOID:0000000003532262
Harness or connectors
(CAN communication line is open or shorted.)
DTC Confirmation ProcedureINFOID:0000000003532263
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 “ENGINE” with CONSULT-II.
3. Start engine and wait for at least 6 seconds.
4. If DTC is detected, go to AT-93, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-II”.
BCIA0031E

DTC U1000 CAN COMMUNICATION LINE
AT-93
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Diagnosis ProcedureINFOID:0000000003532265
1.CHECK CAN COMMUNICATION CIRCUIT
With CONSULT-II1. Turn ignition switch “ON” and start engine.
2. Select “SELF-DIAG RESULTS” mode for “A/T” with CONSULT-
II.
Is any malfunction of the
“CAN COMM CIRCUIT” indicated?
YES >> Print out CONSULT-II screen, GO TO LAN section.
Refer to LAN-38, "
Precaution When Using CONSULT-
II".
NO >>INSPECTION END
PCIA0061E