2004 INFINITI QX56 Factory Service Manual

fuel additives change key battery brake sensor fuel pump trunk release cruise control

Load previous 8 pages

Page 105 of 3371

INFINITI QX56 2004 Factory Service Manual AT-34
A/T CONTROL SYSTEM
Revision: August 20072004 QX56
During Shift Change
The necessary and adequate line pressure for shift change is set.
For this reason, line pressure pattern setting corresponds

Page 106 of 3371

INFINITI QX56 2004 Factory Service Manual A/T CONTROL SYSTEM
AT-35
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
Shift Change System Diagram
*1: Full phase real-time feedback control monitors movement of gear ratio at gear change,

Page 107 of 3371

INFINITI QX56 2004 Factory Service Manual AT-36
A/T CONTROL SYSTEM
Revision: August 20072004 QX56
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 cl

Page 108 of 3371

INFINITI QX56 2004 Factory Service Manual A/T CONTROL SYSTEM
AT-37
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
Engine Brake ControlUCS002CK
The forward one-way clutch transmits the drive force from the engine to the rear wheels.

A/T CONTROL SYSTEM
AT-37
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
Engine Brake ControlUCS002CK
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 ValveUCS002CL
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.)

Page 109 of 3371

INFINITI QX56 2004 Factory Service Manual AT-38
A/T CONTROL SYSTEM
Revision: August 20072004 QX56
FUNCTION OF PRESSURE SWITCH
Input clutch control valveWhen the input clutch is coupled, adjusts the line pressure to the optimum pressure
(inp

AT-38
A/T CONTROL SYSTEM
Revision: August 20072004 QX56
FUNCTION OF 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
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.
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.
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.
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.
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.

Page 110 of 3371

INFINITI QX56 2004 Factory Service Manual ON BOARD DIAGNOSTIC (OBD) SYSTEM
AT-39
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
ON BOARD DIAGNOSTIC (OBD) SYSTEMPFP:00028
IntroductionUCS002CM
The A/T system has two self-diagnostic sy

ON BOARD DIAGNOSTIC (OBD) SYSTEM
AT-39
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
ON BOARD DIAGNOSTIC (OBD) SYSTEMPFP:00028
IntroductionUCS002CM
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 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
OBD-II Function for A/T SystemUCS002C N
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-IIUCS002CO
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)UCS002CP
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.
BCIA0030E

Page 111 of 3371

INFINITI QX56 2004 Factory Service Manual AT-40
ON BOARD DIAGNOSTIC (OBD) SYSTEM
Revision: August 20072004 QX56
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

AT-40
ON BOARD DIAGNOSTIC (OBD) SYSTEM
Revision: August 20072004 QX56
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 AT- 3 9 , "
ON BOARD DIAGNOSTIC (OBD) SYSTEM" .
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-50, "
Emission-related Diagnostic Information" .
Diagnostic trouble codes (DTC)
1st trip diagnostic trouble codes (1st trip DTC)
Freeze frame data
SAT0 1 5K
SAT0 1 6K
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

Page 112 of 3371

INFINITI QX56 2004 Factory Service Manual ON BOARD DIAGNOSTIC (OBD) SYSTEM
AT-41
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
1st trip freeze frame data
System readiness test (SRT) codes
Test values
HOW TO ERASE DTC (WITH CONS

Load next 8 pages

Page: < prev 1-10 ... 73-80 81-88 89-96 97-104 105-112 113-120 121-128 129-136 137-144 ... 3376 next >

oil level fuel tank capacity fuse box diagram warning brake sensor emergency towing