INFINITI FX35 2004 Service Manual

AT-34
A/T CONTROL SYSTEM
Revision: 2004 November 2004 FX35/FX45
Shift Change System Diagram
*1: Full phase real-time feedback control monitors movement of gear ratio at gear change, and controls oil
pressure at real-time to achieve the best gear ratio.
Lock-up ControlACS002LK
The torque converter clutch piston in the torque converter is engaged to eliminate torque converter slip to
increase power transmission efficiency.
The torque converter clutch control valve operation is controlled by the torque converter clutch solenoid valve,
which is controlled by a signal from TCM, and the torque converter clutch control valve engages or releases
the torque converter clutch piston.
Lock-up Operation Condition Table
TORQUE CONVERTER CLUTCH CONTROL VALVE CONTROL
Lock-up Control System Diagram
Lock-up Released

In the lock-up released state, the torque converter clutch control valve is set into the unlocked state by the
torque converter clutch solenoid and the lock-up apply pressure is drained.
In this way, the torque converter clutch piston is not coupled.
PCIA0013E
Selector lever D position M5 position M4 position
Gear position 5454
Lock-up×–××
Slip lock-up××––
PCIA0014E

A/T CONTROL SYSTEM
AT-35
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: 2004 November 2004 FX35/FX45
Lock-up Applied

In the lock-up applied state, the torque converter clutch control valve is set into the locked state by the
torque converter clutch solenoid and lock-up apply pressure is generated.
In this way, the torque converter clutch piston is pressed and coupled.
SMOOTH LOCK-UP CONTROL
When shifting from the lock-up released state to the lock-up applied state, the current output to the torque con-
verter clutch solenoid is controlled with the TCM. In this way, when shifting to the lock-up applied state, the
torque converter clutch is temporarily set to the half-clutched state to reduce the shock.
Half-clutched State

The current output from the TCM to the torque converter clutch solenoid is varied to gradually increase
the torque converter clutch solenoid pressure.
In this way, the lock-up apply pressure gradually rises and while the torque converter clutch piston is put
into half-clutched status, the torque converter clutch piston operating pressure is increased and the cou-
pling is completed smoothly.
Slip Lock-up Control

In the slip region, the torque converter clutch solenoid current is controlled with the TCM to put it into the
half-clutched state. This absorbs the engine torque fluctuation and lock-up operates from low speed.
This raises the fuel efficiency for 4th and 5th gears at both low speed and when the accelerator is
depressed slightly throttle opening.

AT-36
A/T CONTROL SYSTEM
Revision: 2004 November 2004 FX35/FX45
Engine Brake ControlACS002LL

The forward one-way clutch transmits the drive force from the engine to the rear wheels. But the reverse
drive from the rear wheels is not transmitted to the engine because the one-way clutch is idling.
Therefore, the low coast brake solenoid is operated to prevent the forward one-way clutch from idling and
the engine brake is operated in the same manner as conventionally.

The operation of the low coast brake solenoid switches the low coast brake switching valve and controls
the coupling and releasing of the low coast brake.
The low coast brake reducing valve controls the low coast brake coupling force.
Control ValveACS002LM
FUNCTION OF CONTROL VALVE
SCIA1520E
Name Function
Torque converter regulator valveIn order to prevent the pressure supplied to the torque converter from being excessive,
the line pressure is adjusted to the optimum pressure (torque converter operating pres-
sure).
Pressure regulator valve
Pressure regulator plug
Pressure regulator sleeveAdjusts the oil discharged from the oil pump to the optimum pressure (line pressure) for
the driving state.
Front brake control valveWhen the front brake is coupled, adjusts the line pressure to the optimum pressure
(front brake pressure) and supplies it to the front brake. (In 1st, 2nd, 3rd, and 5th gears,
adjusts the clutch pressure.)
Accumulator control valveAdjusts the pressure (accumulator control pressure) acting on the accumulator piston
and low coast reducing valve to the pressure appropriate to the driving state.
Pilot valve AAdjusts the line pressure and produces the constant pressure (pilot pressure) required
for line pressure control, shift change control, and lock-up control.
Pilot valve BAdjusts the line pressure and produces the constant pressure (pilot pressure) required
for shift change control.
Low coast brake switching valve During engine braking, supplies the line pressure to the low coast brake reducing valve.
Low coast brake reducing valveWhen the low coast brake is coupled, adjusts the line pressure to the optimum pressure
(low coast brake pressure) and supplies it to the low coast brake.
N-R accumulator Produces the stabilizing pressure for when N-R is selected.
Direct clutch piston switching valve Operates in 4th gear and switches the direct clutch coupling capacity.
High and low reverse clutch control valveWhen the high and low reverse clutch is coupled, adjusts the line pressure to the opti-
mum pressure (high and low reverse clutch pressure) and supplies it to the high and low
reverse clutch. (In 1st, 3rd, 4th and 5th gears, adjusts the clutch pressure.)

A/T CONTROL SYSTEM
AT-37
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: 2004 November 2004 FX35/FX45
FUNCTION OF ATF PRESSURE SWITCH
Input clutch control valveWhen the input clutch is coupled, adjusts the line pressure to the optimum pressure
(input clutch pressure) and supplies it to the input clutch. (In 4th and 5th gears, adjusts
the clutch pressure.)
Direct clutch control valveWhen the direct clutch is coupled, adjusts the line pressure to the optimum pressure
(direct clutch pressure) and supplies it to the direct clutch. (In 2nd, 3rd, and 4th gears,
adjusts the clutch pressure.)
TCC control valve
TCC control plug
TCC control sleeveSwitches the lock-up to operating or released. Also, by performing the lock-up operation
transiently, lock-up smoothly.
Torque converter lubrication valveOperates during lock-up to switch the torque converter, cooling, and lubrication system
oil path.
Cool bypass valve Allows excess oil to bypass cooler circuit without being fed into it.
Line pressure relief valve Discharges excess oil from line pressure circuit.
N-D accumulator Produces the stabilizing pressure for when N-D is selected.
Manual valveSends line pressure to each circuit according to the select position. The circuits to which
the line pressure is not sent drain. Name Function
Name Function
ATF pressure switch 1 (FR/B)Detects any malfunction in the front brake hydraulic pressure. When it detects any mal-
function, it puts the system into fail-safe mode.
ATF pressure switch 2 (LC/B)Detects any malfunction in the low coast brake hydraulic pressure. When it detects any
malfunction, it puts the system into fail-safe mode.
ATF pressure switch 3 (I/C)Detects any malfunction in the input clutch hydraulic pressure. When it detects any mal-
function, it puts the system into fail-safe mode.
ATF pressure switch 5 (D/C)Detects any malfunction in the direct clutch hydraulic pressure. When it detects any mal-
function, it puts the system into fail-safe mode.
ATF pressure switch 6 (HLR/C)Detects any malfunction in the high and low reverse clutch hydraulic pressure. When it
detects any malfunction, it puts the system into fail-safe mode.

AT-38
ON BOARD DIAGNOSTIC (OBD) SYSTEM
Revision: 2004 November 2004 FX35/FX45
ON BOARD DIAGNOSTIC (OBD) SYSTEMPFP:00028
IntroductionACS002LN
The A/T system has two self-diagnostic systems.
The first is the emission-related on board diagnostic system (OBD-II) performed by the TCM in combination
with the ECM. The malfunction is indicated by the MIL (malfunction indicator lamp) and is stored as a DTC in
the ECM memory but not the TCM memory.
The second is the TCM original self-diagnosis indicated by the A/T CHECK indicator lamp. The malfunction is
stored in the TCM memory. The detected items are overlapped with OBD-II self-diagnostic items. For detail,
refer to AT- 9 4 , "
Display Items List" .
OBD-II Function for A/T SystemACS002LO
The ECM provides emission-related on board diagnostic (OBD-II) functions for the A/T system. One function
is to receive a signal from the TCM used with OBD-related parts of the A/T system. The signal is sent to the
ECM when a malfunction occurs in the corresponding OBD-related part. The other function is to indicate a
diagnostic result by means of the MIL (malfunction indicator lamp) on the instrument panel. Sensors, switches
and solenoid valves are used as sensing elements.
The MIL automatically illuminates in One or Two Trip Detection Logic when a malfunction is sensed in relation
to A/T system parts.
One or Two Trip Detection Logic of OBD-IIACS002LP
ONE TRIP DETECTION LOGIC
If a malfunction is sensed during the first test drive, the MIL will illuminate and the malfunction will be stored in
the ECM memory as a DTC. The TCM is not provided with such a memory function.
TWO TRIP DETECTION LOGIC
When a malfunction is sensed during the first test drive, it is stored in the ECM memory as a 1st trip DTC
(diagnostic trouble code) or 1st trip freeze frame data. At this point, the MIL will not illuminate. — First Trip
If the same malfunction as that experienced during the first test drive is sensed during the second test drive,
the MIL will illuminate. — Second Trip
The “Trip” in the “One or Two Trip Detection Logic” means a driving mode in which self-diagnosis is performed
during vehicle operation.
OBD-II Diagnostic Trouble Code (DTC)ACS002LQ
HOW TO READ DTC AND 1ST TRIP DTC
DTC and 1st trip DTC can be read by the following methods.
( with CONSULT-II or GST) CONSULT-II or GST (Generic Scan Tool) Examples: P0705, P0720 etc.
These DTC are prescribed by SAE J2012.
(CONSULT-II also displays the malfunctioning component or system.)

1st trip DTC No. is the same as DTC No.

Output of the diagnostic trouble code indicates that the indicated circuit has a malfunction. How-
ever, in case of the Mode II and GST, they do not indicate whether the malfunction is still occurring
or occurred in the past and returned to normal.
CONSULT-II can identify them as shown below, therefore, CONSULT-II (if available) is recom-
mended.
A sample of CONSULT-II display for DTC and 1st trip DTC is shown
on the next page. DTC or 1st trip DTC of a malfunction is displayed
in SELF-DIAGNOSTIC RESULTS mode for “ENGINE” with CON-
SULT-II. Time data indicates how many times the vehicle was driven
after the last detection of a DTC.
SAT014K

ON BOARD DIAGNOSTIC (OBD) SYSTEM
AT-39
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: 2004 November 2004 FX35/FX45
If the DTC is being detected currently, the time data will be “0”.
If a 1st trip DTC is stored in the ECM, the time data will be “1t”.
Freeze Frame Data and 1st Trip Freeze Frame Data
The ECM has a memory function, which stores the driving condition such as fuel system status, calculated
load value, engine coolant temperature, short term fuel trim, long term fuel trim, engine speed and vehicle
speed at the moment the ECM detects a malfunction.
Data which are stored in the ECM memory, along with the 1st trip DTC, are called 1st trip freeze frame data,
and the data, stored together with the DTC data, are called freeze frame data and displayed on CONSULT-II
or GST. The 1st trip freeze frame data can only be displayed on the CONSULT-II screen, not on the GST. For
detail, refer to EC-109, "
CONSULT-II Function" (for VQ35DE) or EC-759, "CONSULT-II Function" (for
VK45DE).
Only one set of freeze frame data (either 1st trip freeze frame data of freeze frame data) can be stored in the
ECM. 1st trip freeze frame data is stored in the ECM memory along with the 1st trip DTC. There is no priority
for 1st trip freeze frame data and it is updated each time a different 1st trip DTC is detected. However, once
freeze frame data (2nd trip detection/MIL on) is stored in the ECM memory, 1st trip freeze frame data is no
longer stored. Remember, only one set of freeze frame data can be stored in the ECM. The ECM has the fol-
lowing priorities to update the data.
Both 1st trip freeze frame data and freeze frame data (along with the DTC) are cleared when the ECM mem-
ory is erased.
HOW TO ERASE DTC
The diagnostic trouble code can be erased by CONSULT-II, GST or ECM DIAGNOSTIC TEST MODE as
described following.

If the battery cable is disconnected, the diagnostic trouble code will be lost within 24 hours.

When you erase the DTC, using CONSULT-II or GST is easier and quicker than switching the mode
selector on the ECM.
The following emission-related diagnostic information is cleared from the ECM memory when erasing DTC
related to OBD-II. For details, refer to EC-54, "
Emission-Related Diagnostic Information" (for VQ35DE) or EC-
704, "Emission-related Diagnostic Information" (for VK45DE).

Diagnostic trouble codes (DTC)
SAT015K
SAT016K
Priority Items
1 Freeze frame data Misfire — DTC: P0300 - P0306
Fuel Injection System Function — DTC: P0171, P0172, P0174, P0175
2 Except the above items (Includes A/T related items)
3 1st trip freeze frame data

AT-40
ON BOARD DIAGNOSTIC (OBD) SYSTEM
Revision: 2004 November 2004 FX35/FX45

1st trip diagnostic trouble codes (1st trip DTC)

Freeze frame data

1st trip freeze frame data

System readiness test (SRT) codes

Test values
HOW TO ERASE DTC (WITH CONSULT-II)

If a DTC is displayed for both ECM and TCM, it is necessary to be erased for both ECM and TCM.
1. If the ignition switch stays “ON” after repair work, be sure to turn ignition switch “OFF” once. Wait at least
10 seconds and then turn it “ON” (engine stopped) again.
2. Turn CONSULT-II “ON” and touch “A/T”.
3. Touch “SELF-DIAG RESULTS”.
4. Touch “ERASE”. (The DTC in the TCM will be erased.) Then touch “BACK” twice.
5. Touch “ENGINE”.
6. Touch “SELF-DIAG RESULTS”.
7. Touch “ERASE”. (The DTC in the ECM will be erased.)
HOW TO ERASE DTC (WITH GST)
1. If the ignition switch stays “ON” after repair work, be sure to turn ignition switch “OFF” once. Wait at least
10 seconds and then turn it “ON” (engine stopped) again.
2. Perform “TCM SELF-DIAGNOSTIC PROCEDURE (NO TOOLS)”. Refer to AT- 1 0 3 , "
TCM SELF-DIAG-
NOSTIC PROCEDURE (NO TOOLS)" . (The engine warm-up step can be skipped when performing the
diagnosis only to erase the DTC.)
3. Select Mode 4 with Generic Scan Tool (GST). For details, refer to EC-122, "
Generic Scan Tool (GST)
Function" (for VQ35DE) or EC-772, "Generic Scan Tool (GST) Function" (for VK45DE).
SCIA5671E

ON BOARD DIAGNOSTIC (OBD) SYSTEM
AT-41
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: 2004 November 2004 FX35/FX45
HOW TO ERASE DTC (NO TOOLS)
The A/T CHECK indicator lamp is located on the instrument panel.
1. If the ignition switch stays “ON” after repair work, be sure to turn ignition switch “OFF” once. Wait at least
10 seconds and then turn it “ON” (engine stopped) again.
2. Perform “TCM SELF-DIAGNOSTIC PROCEDURE (NO TOOLS)”. Refer to AT- 1 0 3 , "
TCM SELF-DIAG-
NOSTIC PROCEDURE (NO TOOLS)" (The engine warm-up step can be skipped when performing the
diagnosis only to erase the DTC.)
3. Perform “OBD-II SELF-DIAGNOSTIC PROCEDURE (NO TOOLS)”. Refer to EC-67, "
How to Erase DTC"
(for VQ35DE) or EC-715, "How to Erase DTC" (for VK45DE).
Malfunction Indicator Lamp (MIL)ACS002LR
DESCRIPTION
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-39, "WARNING
LAMPS" , or see EC-641, "MIL AND DATA LINK CONNEC-
TOR" (for VQ35DE) or EC-1318, "MIL AND DATA LINK
CONNECTOR" (for VK45DE).
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

AT-42
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
TROUBLE DIAGNOSISPFP:00004
DTC Inspection Priority ChartACS007A2
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 DTC, first perform the trouble diagnosis for “DTC U1000 CAN
COMMUNICATION LINE”. Refer to AT- 1 0 5
.
Fail-SafeACS007A3
The TCM has an electrical fail-safe mode. This mode makes it possible to operate even if there is a an mal-
function 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 or 4th (depend-
ing on the breakdown position), so the customer should feel “slipping” or “poor acceleration”. When fail-safe
mode is triggered, when the ignition switch is switched “ON”, the A/T CHECK indicator lamp flashes for about
8 seconds. (Refer to AT- 1 0 3 , "
TCM SELF-DIAGNOSTIC PROCEDURE (NO TOOLS)" ).
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. Also, the A/T CHECK indicator lamp flashes for about 8 seconds once, then is
cleared. Therefore, the customer's vehicle has returned to normal, so handle according to the “diagnostics
flow” (Refer to AT- 4 5
).
FAIL-SAFE FUNCTION
If any malfunction occurs in a sensor or solenoid, this function controls the A/T to make driving possible.
Vehicle Speed Sensor A/T (Revolution 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 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 accord-
ing to a pre-determined accelerator angle to make driving possible. 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 accord-
ing to a pre-determined accelerator angle to make driving possible. 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 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.)
Priority Detected items (DTC)
1 U1000 CAN communication line
2 Except above

TROUBLE DIAGNOSIS
AT-43
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: 2004 November 2004 FX35/FX45
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 executed.
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 malfunction (electrical or functional) occurs, in order to make driving possible, if the solenoid is
“ON”, the transmission is held in 2nd gear; if the solenoid is “OFF”, the transmission is held in 4th gear.
(engine brake is not applied in 1st and 2nd gear.)
Input Clutch Solenoid

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

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

If a malfunction (electrical or functional) 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 functional) 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 and manual mode are pro-
hibited.
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