2008 INFINITI FX35 Brake System

TROUBLE DIAGNOSISAT-41
< SERVICE INFORMATION >
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TROUBLE DIAGNOSIS
DTC Inspection Priority ChartINFOID:0000000001327148
If some DTCs are displayed at the same time, per form inspections one by one based on the following priority
chart.
NOTE:
If “DTC U1000” is displayed with other DTCs, fi rst perform the trouble diagnosis for “DTC U1000 CAN
COMMUNICATION”. Refer to AT- 9 4
.
Fail-SafeINFOID:0000000001327149
The TCM has an electrical fail-safe mode. This mode make s it possible to operate even if there is an error in a
main electronic control input/output signal circuit.
In fail-safe mode, even if the selector lever is “D” or “M” 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 s pecial conditions (for example, when slamming on the
brake with the wheels spinning drastically and stopping the ti re 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, t he customer's vehicle has returned to normal, so handle according to the
“WORK FLOW” (Refer to AT- 4 2
).
FAIL-SAFE FUNCTION
If any malfunction occurs in a sensor or solenoid, th is 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 trans-
mission and from combination meter so normal driving is possible even if there is a malfunction in one of the
systems. And if vehicle speed sens or A/T (revolution sensor) has unus ual cases, 5th gear and manual mode
are prohibited.
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 po ssible. And if there are malfunctions in tow systems,
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 po ssible. And if there are malfunctions in tow systems,
the accelerator opening angle is controlled by the idle signal sent from the ECM which is based on input indi-
cating 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 t he TCM, the position indicator is switched OFF, the
starter relay is switched OFF (starter starting is di sabled), the back-up lamp relay switched OFF (back-up lamp
is OFF) and the position is fixed to the “D” position 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, t he A/T is fixed in 2nd gear to make driving possible.
NOTE:
When the vehicle is driven fixed in 2nd gear, a turbine revolution sensor malfunction is displayed,
but this is not a turbine r evolution sensor malfunction.
 When the coupling pattern below is detected, the fail- safe action corresponding to the pattern is performed.
A/T 1st Engine Braking
Priority Detected items (DTC)
1 U1000 CAN communication line
2 Except above
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AT-42
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
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 malfunction (electrical or functional) occurs, in or der to make driving possible, if the solenoid is ON,
the transmission is held in 2nd gear; if the solenoid is OFF, the A/T is held in 4th gear. (Engine brake is not
applied in 1st and 2nd gear.)
Input Clutch Solenoid
If a malfunction (electrical or functi onal) occurs with the solenoid either ON or OFF, the A/T is held in 4th gear
to make driving possible.
Direct Clutch Solenoid
If a malfunction (electrical or functi onal) occurs with the solenoid either ON or OFF, the A/T is held in 4th gear
to make driving possible.
Front Brake Solenoid
If a malfunction (electrical or functi onal) 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 malfunction (electrical or functi onal) occurs with the solenoid either ON or OFF, the A/T 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 turbi ne revolution sensors, 5th gear and manual mode are prohib-
ited.
How to Perform Trouble Diagnosis for Quick and Accurate RepairINFOID:0000000001327150
INTRODUCTION
The TCM receives a signal from the vehicle speed sensor , accelerator pedal position sensor (throttle position
sensor) or PNP switch and provides shift cont rol or lock-up control via A/T solenoid valves.
The TCM also communicates with the ECM by means of a signal
sent from sensing elements used with the OBD-related parts of the
A/T system for malfunction-diagnos tic purposes. The TCM is capa-
ble of diagnosing malfunctioning parts while the ECM can store mal-
functions in its memory.
Input and output signals must always be correct and stable in the
operation of the A/T system. The A/T system must be in good oper-
ating condition and be free of valve seizure, solenoid valve malfunc-
tion, etc.
It is much more difficult to diagnose a error that occurs intermittently
rather than continuously. Most inte rmittent errors are caused by poor
electric connections or improper wiring. In this case, careful check-
ing of suspected circuits may help prevent the replacement of good
parts.
A visual check only may not find the cause of the errors. A road test
with CONSULT-III (or GST) or a circuit tester connected should be
performed. Follow the "WORK FLOW".
SAT631IB
SAT632I
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TROUBLE DIAGNOSISAT-47
< SERVICE INFORMATION >
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44-3. Part 2
AT- 5 3
❏ AT- 1 8 0 , "Vehicle Cannot Be Started from D1".
❏ AT- 1 8 2 , "
A/T Does Not Shift: D1→ D2".
❏ AT- 1 8 4 , "
A/T Does Not Shift: D2→ D3".
❏ AT- 1 8 6 , "
A/T Does Not Shift: D3→ D4".
Part 3 AT- 5 3
❏ AT- 1 9 5 , "Cannot Be Changed to Manual Mode".
❏ AT- 1 9 6 , "
A/T Does Not Shift: 5th Gear → 4th Gear".
❏ AT- 1 9 7 , "
A/T Does Not Shift: 4th Gear → 3rd Gear".
❏ AT- 1 9 9 , "
A/T Does Not Shift: 3rd Gear → 2nd Gear".
❏ AT- 2 0 1 , "
A/T Does Not Shift: 2nd Gear → 1st Gear".
❏ AT- 2 0 2 , "
Vehicle Does Not Decelerate by Engine Brake".
❏ Perform self-diagnostics. Enter checks for detected items. AT- 8 4
, AT- 9 1.
❏ DTC U1000 CAN CO MMUNICATION LINE AT- 9 4
.
❏ DTC P0615 START SIGNAL CIRCUIT AT- 9 7
.
❏ DTC P0700 TCM AT- 1 0 1
❏ DTC P0705 PARK/NEUTRAL POSITION SWITCH AT- 1 0 2.
❏ DTC P0717 TURBINE REVOLUTION SENSOR AT- 1 0 6
.
❏ DTC P0720 VEHICLE SPEED SENS OR A/T (REVOLUTION SENSOR) AT- 1 0 8
.
❏ DTC P0725 ENGINE SPEED SIGNAL AT- 11 2
.
❏ DTC P0731 A/T 1ST GEAR FUNCTION AT- 11 4
.
❏ DTC P0732 A/T 2ND GEAR FUNCTION AT- 11 6
.
❏ DTC P0733 A/T 3RD GEAR FUNCTION AT- 11 8
.
❏ DTC P0734 A/T 4TH GEAR FUNCTION AT- 1 2 0
.
❏ DTC P0735 A/T 5TH GEAR FUNCTION AT- 1 2 2
.
❏ DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE AT- 1 2 4
.
❏ DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP) AT-126
.
❏ DTC P0745 LINE PRESSURE SOLONOID VALVE AT- 1 2 8
.
❏ DTC P1705 THROTTLE POSITION SENSOR AT- 1 3 0
.
❏ DTC P1710 A/T FLUID TEMPERATURE SENSOR CIRCUIT AT- 1 3 2
.
❏ DTC P1721 VEHICLE SPEED SENSOR MTR AT- 1 3 7
.
❏ DTC P1730 A/T INTERLOCK AT- 1 3 9
.
❏ DTC P1731 A/T 1ST ENGINE BRAKING AT- 1 4 1
.
❏ DTC P1752 INPUT CLUTCH SOLENOID VALVE AT- 1 4 3
.
❏ DTC P1757 FRONT BRAKE SOLENOID VALVE AT- 1 4 5
.
❏ DTC P1762 DIRECT CLUTCH SOLENOID VALVE AT- 1 4 7
.
❏ DTC P1767 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE AT- 1 4 9
.
❏ DTC P1772 LOW COAST BRAKE SOLENOID VALVE AT- 1 5 1
.
❏ DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION AT- 1 5 3
.
❏ DTC P1815 MANUAL MODE SWITCH AT-155
.
5 ❏ Inspect each system for items found to be NG in the self-diagnostics and repair or replace the malfunctioning parts.
6 ❏ Perform all road tests and enter the checks again for the required items. AT- 4 9
7❏
For any remaining NG items, perform the “diagnostics procedure” and repair or replace the malfunctioning
parts. See the chart for diagnostics by symptoms. (This chart also contains other symptoms and inspection pro-
cedures.) AT- 5 9
8
❏ Erase the results of the self-diagnostics from the TCM and the ECM. AT- 8 4,
AT-
91
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AT-52
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
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 andthe stall speed.
CAUTION:
 Keep the brake pedal pressed all the way down duringmeasurement.
 When measuring the line pressure at the stall speed, refer to "STALL TEST".
7. After the measurements are complete, install the oil pressure detection plug and tighten to the specified torque.
CAUTION:
 Do not reuse the O-ring.
 Apply ATF to the O-ring.
Line Pressure
Judgement of Line Pressure Test
SCIA7463E
:7.3 N·m (0.74 kg-m, 65 in-lb)SAT493G
Engine speed Line pressure kPa (kg/cm
2, psi)
“R” position “D” and “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 speed Low for all positions
(“P”, “R”, “N”, “D”,
“M”)
Possible causes include malfunctions in the pressure supply system and low oil pump output.
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 spe-
cific position Possible causes include an oil pressure leak in a passage or device related to the position after
the pressure is distributed by the manual valve.
High Possible causes include a sensor malfunction or malfunction in the line pressure adjustment func-
tion.
For example
 Accelerator pedal position signal malfunction
 ATF temperature sensor malfunction
 Line pressure solenoid malfunction (sticking in OFF state, filter clog, cut line)
 Pressure regulator valve or plug sticking
:

AT-64
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
18Slips/Will
Not En-
gage When “D” or “M” posi-
tion, remains in 1st
gear. ON vehicle
1. A/T fluid level and state
AT- 4 9
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 7
3. Direct clutch solenoid valve AT- 1 4 7
4. Line pressure test AT- 4 9
5. CAN communication lineAT- 9 4
6. Control valve with TCMAT- 2 1 5
OFF vehicle7. 3rd one-way clutch
AT- 2 8 7
8. 1st one-way clutchAT- 2 9 5
9. Gear systemAT- 2 4 9
10. Reverse brakeAT- 2 6 7
11. Forward one-way clutch (Parts behind drum support is im-
possible to perform inspection by disassembly. Refer to AT-
16, "Cross-Sectional View (2WD Models)", AT- 1 7 , "Cross-
Sectional View (VQ35DE Models for AWD)" or AT- 1 8 , "Cross-
Sectional View (VK45DE Models for AWD)") AT- 2 6 7
12. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to
AT- 1 6 , "
Cross-
Sectional View (2WD Models)", AT- 1 7 , "Cross-Sectional View
(VQ35DE Models for AWD)" or AT- 1 8 , "Cross-Sectional View
(VK45DE Models for AWD)") AT- 2 6 7
No. Items Symptom Condition Diagnostic Item
Reference
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TROUBLE DIAGNOSISAT-65
< SERVICE INFORMATION >
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19
Slips/Will
Not En-
gage When “D” or “M” posi-
tion, remains in 2nd
gear.
ON vehicle
1. A/T fluid level and state
AT- 4 9
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 7
3. Low coast brake solenoid valve AT- 1 5 1
4. Line pressure test AT- 4 9
5. CAN communication lineAT- 9 4
6. Control valve with TCMAT- 2 1 5
OFF vehicle7. 3rd one-way clutch
AT- 2 8 7
8. Gear systemAT- 2 4 9
9. Direct clutchAT- 3 0 3
10. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 6 , "
Cross-
Sectional View (2WD Models)", AT- 1 7 , "Cross-Sectional View
(VQ35DE Models for AWD)" or AT- 1 8 , "Cross-Sectional View
(VK45DE Models for AWD)") AT- 2 6 7
20
When “D” or “M” posi-
tion, remains in 3rd
gear. ON vehicle
1. A/T fluid level and state
AT- 4 9
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 7
3. Line pressure test AT- 4 9
4. CAN communication lineAT- 9 4
5. Control valve with TCMAT- 2 1 5
OFF vehicle6. 3rd one-way clutch
AT- 2 8 7
7. Gear systemAT- 2 4 9
8. High and low reverse clutchAT- 3 0 1
9. Forward one-way clutch (Parts behind drum support is im-
possible to perform inspection by disassembly. Refer to AT-
16, "Cross-Sectional View (2WD Models)", AT- 1 7 , "Cross-
Sectional View (VQ35DE Models for AWD)" or AT- 1 8 , "Cross-
Sectional View (VK45DE Models for AWD)") AT- 2 6 7
10. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to
AT- 1 6 , "
Cross-
Sectional View (2WD Models)", AT- 1 7 , "Cross-Sectional View
(VQ35DE Models for AWD)" or AT- 1 8 , "Cross-Sectional View
(VK45DE Models for AWD)") AT- 2 6 7
No. Items Symptom Condition Diagnostic Item
Reference
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AT-66
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
21Slips/Will
Not En-
gage When “D” or “M” posi-
tion, remains in 4th
gear.
ON vehicle1. A/T fluid level and state
AT- 4 9
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 7
3. Input clutch solenoid valve AT- 1 4 3
4. Direct clutch solenoid valveAT- 1 4 7
5. High and low reverse clutch solenoid valveAT- 1 4 9
6. Low coast brake solenoid valveAT- 1 5 1
7. Front brake solenoid valveAT- 1 4 5
8. Line pressure test AT- 4 9
9. CAN communication lineAT- 9 4
10. Control valve with TCMAT- 2 1 5
OFF vehicle11. Input clutch
AT- 2 8 912. Gear systemAT- 2 4 9
13. High and low reverse clutchAT- 3 0 1
14. Direct clutchAT- 3 0 3
22When “D” or “M” posi-
tion, remains in 5th
gear. ON vehicle1. A/T fluid level and state
AT- 4 9
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 7

3. Front brake solenoid valve AT- 1 4 5
4. Line pressure test AT- 4 9
5. CAN communication lineAT- 9 4
6. Control valve with TCMAT- 2 1 5
OFF vehicle7. Front brake (brake band)
AT- 2 6 78. Input clutchAT- 2 8 9
9. Gear systemAT- 2 4 9
10. High and low reverse clutchAT- 3 0 1
No. Items Symptom Condition Diagnostic Item Reference
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TROUBLE DIAGNOSISAT-67
< SERVICE INFORMATION >
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23
Slips/Will
Not En-
gage Vehicle cannot be
started from D
1.
Refer to AT- 1 8 0 , "
Ve-
hicle Cannot Be Start-
ed from D1". ON vehicle
1. A/T fluid level and state
AT- 4 9
2. Accelerator pedal position sensorAT- 1 3 0
3. Line pressure test AT- 4 9
4. CAN communication lineAT- 9 4
5. Control valve with TCMAT- 2 1 5
OFF vehicle6. Torque converter
AT- 2 6 7
7. Oil pump assemblyAT- 2 8 5
8. 3rd one-way clutchAT- 2 8 7
9. 1st one-way clutch AT- 2 9 5
10. Gear systemAT- 2 4 9
11. Reverse brakeAT- 2 6 7
12. Forward one-way clutch (Parts behind drum support is im-
possible to perform inspection by disassembly. Refer to AT-
16, "Cross-Sectional View (2WD Models)", AT- 1 7 , "Cross-
Sectional View (VQ35DE Models for AWD)" or AT- 1 8 , "Cross-
Sectional View (VK45DE Models for AWD)") AT- 2 6 7
13. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to
AT- 1 6 , "
Cross-
Sectional View (2WD Models)", AT- 1 7 , "Cross-Sectional View
(VQ35DE Models for AWD)" or AT- 1 8 , "Cross-Sectional View
(VK45DE Models for AWD)") AT- 2 6 7
24
Does not lock-up.
Refer to
AT- 1 9 0 , "A/T
Does Not Lock-up".ON vehicle 1. A/T fluid level and state
AT- 4 9
2. Line pressure testAT- 4 9
3. Engine speed signalAT- 11 2
4. Turbine revolution sensorAT- 1 0 6
5. Torque converter clutch solenoid valveAT- 1 2 4
6. CAN communication line AT- 9 4
7. Control valve with TCMAT- 2 1 5
OFF vehicle8. Torque converter
AT- 2 6 79. Oil pump assemblyAT- 2 8 5
25Does not hold lock-up
condition.
Refer to
AT- 1 9 2 , "A/T
Does Not Hold Lock-
up Condition". ON vehicle 1. A/T fluid level and state
AT- 4 9
2. Line pressure testAT- 4 9
3. Engine speed signalAT- 11 2
4. Turbine revolution sensorAT- 1 0 6
5. Torque converter clutch solenoid valveAT- 1 2 4
6. CAN communication line AT- 9 4
7. Control valve with TCMAT- 2 1 5
OFF vehicle8. Torque converter
AT- 2 6 79. Oil pump assemblyAT- 2 8 5
No. Items Symptom Condition Diagnostic Item Reference
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