AT-30
A/T CONTROL SYSTEM
Revision: 2006 November2007 350Z
CAN CommunicationNCS0001N
SYSTEM DESCRIPTION
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 error detection ability. Many elec-
tronic 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 connected 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. For details, refer to LAN-48,
"CAN System Specification Chart" .
Input/Output Signal of TCMNCS0001O
*1: Spare for vehicle speed sensor A/T (revolution sensor)
*2: Spare for accelerator pedal position signal
*3: If these input and output signals are different, the TCM triggers the fail-safe function.
*4: Used as a condition for starting self-diagnostics; if self-diagnostics are not started, it is judged that there is some kind of error.
*5: Input by CAN communications
*6: Output by CAN communicationsControl itemLine
pressure
controlVehicle
speed
controlShift
controlLock-up
controlEngine
brake
controlFail-safe
function
(*3)
Self-diag-
nostics
function
InputAccelerator pedal position signal
(*5)XXXXX X X
Vehicle speed sensor A/T
(revolution sensor)XXXXX X X
Vehicle speed sensor MTR
(*1)(*5)X
Closed throttle position signal
(*5)X(*2)XX X
X(*4)
Wide open throttle position signal(*5)X
X(*4)
Turbine revolution sensor 1 X X X X X
Turbine revolution sensor 2
(for 4th speed only)XXXXX
Engine speed signals
(*5)XXXXX X X
Stop lamp switch signal
(*5)XXX
X(*4)
A/T fluid temperature sensors 1, 2 X X X X X X
ASCDOperation signal
(*5)XXX
Overdrive cancel sig-
nal
(*5)X
OutputDirect clutch solenoid X X X X
Input clutch solenoid X X X X
High and low reverse clutch solenoid X X X X
Front brake solenoid X X X X
Low coast brake solenoid
(ATF pressure switch 2)XX X X X
Line pressure solenoid X X X X X X X
TCC solenoid X X X
Self-diagnostics table
(*6)X
Starter relayXX
A/T CONTROL SYSTEM
AT-35
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Revision: 2006 November2007 350Z
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 coupling 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 has a low
degree of opening.
Engine Brake ControlNCS0001S
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 ValveNCS0001T
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.)
AT-36
A/T CONTROL SYSTEM
Revision: 2006 November2007 350Z
FUNCTION OF ATF PRESSURE SWITCH
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.)
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 passage.
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 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.
TROUBLE DIAGNOSIS
AT-41
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Revision: 2006 November2007 350Z
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 interlock is detected at the 3rd gear or more, it is locked at the 2nd gear.
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 A/T 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 functional) 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 functional) 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 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 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 turbine revolution sensors, 5th gear and manual mode are prohib-
ited.
AT-44
TROUBLE DIAGNOSIS
Revision: 2006 November2007 350Z
DIAGNOSTIC WORKSHEET
Information from Customer
KEY POINTS
WHAT..... Vehicle & A/T model
WHEN..... Date, Frequencies
WHERE..... Road conditions
HOW..... Operating conditions, Symptoms
Diagnostic Worksheet Chart
Customer name MR/MS Model & Year VIN
Trans. Model Engine Mileage
Incident Date Manuf. Date In Service Date
Frequency❏ Continuous❏ Intermittent ( times a day)
Symptoms❏ Vehicle does not move. (❏ Any position❏ Particular position)
❏ No up-shift (❏ 1st → 2nd❏ 2nd → 3rd❏ 3rd → 4th ❏ 4th → 5th)
❏ No down-shift (❏ 5th → 4th ❏ 4th → 3rd❏ 3rd → 2nd❏ 2nd → 1st)
❏ Lock-up malfunction
❏ Shift point too high or too low.
❏ Shift shock or slip (❏ N → D❏ Lock-up❏ Any drive position)
❏ Noise or vibration
❏ No kick down
❏ No pattern select
❏ Others
()
A/T CHECK indicator lamp❏ Continuously lit❏ Not lit
Malfunction indicator lamp (MIL)❏ Continuously lit❏ Not lit
1❏ Read the item on cautions concerning fail-safe and understand the customer's complaint.AT- 4 0
2❏ A/T fluid inspectionAT- 4 9❏ Leak (Repair leak location.)
❏ State
❏ Amount
3❏ Stall test and line pressure testAT- 4 9
,
AT- 5 0
❏ Stall test
❏ Torque converter one-way clutch
❏ Front brake
❏ High and low reverse clutch
❏ Low coast brake
❏ Forward brake
❏ Reverse brake
❏ Forward one-way clutch❏ 1st one-way clutch
❏ 3rd one-way clutch
❏ Engine
❏ Line pressure low
❏ Except for input clutch and direct
clutch, clutches and brakes OK
❏ Line pressure inspection - Suspected part:
TROUBLE DIAGNOSIS
AT-45
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Revision: 2006 November2007 350Z
4❏ Perform all road tests and enter checks in required inspection items.AT- 5 2
4-1.Check before engine is started AT- 5 3
❏ AT- 1 7 2 , "A/T Check Indicator Lamp Does Not Come On"
❏ Perform self-diagnostics. Enter checks for detected items. AT- 8 6 , AT- 9 2
❏ AT-94, "DTC U1000 CAN COMMUNICATION LINE"
❏ AT-97, "DTC P0615 START SIGNAL CIRCUIT"
❏ AT-101, "DTC P0700 TCM"
❏ AT-102, "DTC P0705 PARK/NEUTRAL POSITION SWITCH"
❏ AT-106, "DTC P0717 TURBINE REVOLUTION SENSOR"
❏ AT-108, "DTC P0720 VEHICLE SPEED SENSOR A/T (REVOLUTION SENSOR)"
❏ AT-113, "DTC P0725 ENGINE SPEED SIGNAL"
❏ AT-115, "DTC P0731 A/T 1ST GEAR FUNCTION"
❏ AT-117, "DTC P0732 A/T 2ND GEAR FUNCTION"
❏ AT-119, "DTC P0733 A/T 3RD GEAR FUNCTION"
❏ AT-121, "DTC P0734 A/T 4TH GEAR FUNCTION"
❏ AT-123, "DTC P0735 A/T 5TH GEAR FUNCTION"
❏ AT-125, "DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE"
❏ AT-127, "DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)"
❏ AT-129, "DTC P0745 LINE PRESSURE SOLENOID VALVE"
❏ AT-131, "DTC P1705 THROTTLE POSITION SENSOR"
❏ AT-134, "DTC P1710 A/T FLUID TEMPERATURE SENSOR CIRCUIT"
❏ AT-139, "DTC P1721 VEHICLE SPEED SENSOR MTR"
❏ AT-141, "DTC P1730 A/T INTERLOCK"
❏ AT-143, "DTC P1731 A/T 1ST ENGINE BRAKING"
❏ AT-145, "DTC P1752 INPUT CLUTCH SOLENOID VALVE"
❏ AT-147, "DTC P1757 FRONT BRAKE SOLENOID VALVE"
❏ AT-149, "DTC P1762 DIRECT CLUTCH SOLENOID VALVE"
❏ AT-151, "DTC P1767 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE"
❏ AT-153, "DTC P1772 LOW COAST BRAKE SOLENOID VALVE"
❏ AT-155, "DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION"
❏ AT-157, "DTC P1815 MANUAL MODE SWITCH"
4-2.Check at IdleAT- 5 3
❏ AT- 1 7 3 , "Engine Cannot Be Started in “P” or “N” Position"
❏ AT- 1 7 3 , "In “P” Position, Vehicle Moves When Pushed"
❏ AT- 1 7 4 , "In “N” Position, Vehicle Moves"
❏ AT- 1 7 5 , "Large Shock (“N” to “D” Position)"
❏ AT- 1 7 7 , "Vehicle Does Not Creep Backward in “R” Position"
❏ AT- 1 7 9 , "Vehicle Does Not Creep Forward in “D” Position"
4-3.Cruise testAT- 5 5
Part 1
❏ AT- 1 8 1 , "
Vehicle Cannot Be Started from D1"
❏ AT- 1 8 3 , "A/T Does Not Shift: D1 → D2"
❏ AT- 1 8 5 , "A/T Does Not Shift: D2 → D3"
❏ AT- 1 8 7 , "A/T Does Not Shift: D3 → D4"
❏ AT- 1 8 9 , "A/T Does Not Shift: D4 → D5"
❏ AT- 1 9 1 , "A/T Does Not Lock-up"
❏ AT- 1 9 3 , "A/T Does Not Hold Lock-up Condition"
❏ AT- 1 9 4 , "Lock-up Is Not Released"
❏ AT- 1 9 5 , "Engine Speed Does Not Return to Idle"
AT-46
TROUBLE DIAGNOSIS
Revision: 2006 November2007 350Z
44-3.Part 2AT- 5 7
❏ AT-181, "Vehicle Cannot Be Started from D1"
❏ AT-183, "A/T Does Not Shift: D1 → D2"
❏ AT-185, "A/T Does Not Shift: D2 → D3"
❏ AT-187, "A/T Does Not Shift: D3 → D4"
Part 3AT- 5 8
❏ AT-196, "Cannot Be Changed to Manual Mode"
❏ AT-196, "A/T Does Not Shift: 5th Gear → 4th Gear"
❏ AT-198, "A/T Does Not Shift: 4th Gear → 3rd Gear"
❏ AT-199, "A/T Does Not Shift: 3rd Gear → 2nd Gear"
❏ AT-201, "A/T Does Not Shift: 2nd Gear → 1st Gear"
❏ AT-202, "Vehicle Does Not Decelerate by Engine Brake"
❏ Perform self-diagnostics. Enter checks for detected items. AT- 8 6 , AT- 9 2
❏ AT- 9 4 , "DTC U1000 CAN COMMUNICATION LINE"
❏ AT- 9 7 , "DTC P0615 START SIGNAL CIRCUIT"
❏ AT-101, "DTC P0700 TCM"
❏ AT-102, "DTC P0705 PARK/NEUTRAL POSITION SWITCH"
❏ AT-106, "DTC P0717 TURBINE REVOLUTION SENSOR"
❏ AT-108, "DTC P0720 VEHICLE SPEED SENSOR A/T (REVOLUTION SENSOR)"
❏ AT- 11 3 , "DTC P0725 ENGINE SPEED SIGNAL"
❏ AT- 11 5 , "DTC P0731 A/T 1ST GEAR FUNCTION"
❏ AT- 11 7 , "DTC P0732 A/T 2ND GEAR FUNCTION"
❏ AT- 11 9 , "DTC P0733 A/T 3RD GEAR FUNCTION"
❏ AT-121, "DTC P0734 A/T 4TH GEAR FUNCTION"
❏ AT-123, "DTC P0735 A/T 5TH GEAR FUNCTION"
❏ AT-125, "DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE"
❏ AT-127, "DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)"
❏ AT-129, "DTC P0745 LINE PRESSURE SOLENOID VALVE"
❏ AT-131, "DTC P1705 THROTTLE POSITION SENSOR"
❏ AT-134, "DTC P1710 A/T FLUID TEMPERATURE SENSOR CIRCUIT"
❏ AT-139, "DTC P1721 VEHICLE SPEED SENSOR MTR"
❏ AT-141, "DTC P1730 A/T INTERLOCK"
❏ AT-143, "DTC P1731 A/T 1ST ENGINE BRAKING"
❏ AT-145, "DTC P1752 INPUT CLUTCH SOLENOID VALVE"
❏ AT-147, "DTC P1757 FRONT BRAKE SOLENOID VALVE"
❏ AT-149, "DTC P1762 DIRECT CLUTCH SOLENOID VALVE"
❏ AT-151, "DTC P1767 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE"
❏ AT-153, "DTC P1772 LOW COAST BRAKE SOLENOID VALVE"
❏ AT-155, "DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION"
❏ AT-157, "DTC P1815 MANUAL MODE SWITCH"
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- 5 2
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 TCM and ECM.AT- 9 3,
AT- 3 8
AT-50
TROUBLE DIAGNOSIS
Revision: 2006 November2007 350Z
8. Cool down the ATF.
CAUTION:
Run the engine at idle for at least one minute.
9. Repeat steps 5 through 8 with selector lever in “R” position.
Judgment Stall Test
O: Stall speed within standard value position
H: Stall speed higher than standard value
L: Stall speed lower than standard value
Stall Test Standard Value Position
LINE PRESSURE TEST
Line Pressure Test Port
Line Pressure Test Procedure
1. Inspect the amount of engine oil and replenish if necessary.
2. Drive the car for about 10 minutes to warm it up so that the ATF reaches in range of 50 to 80°C (122 to
176°F), then inspect the amount of ATF and replenish if necessary.
NOTE:
The A/T fluid temperature rises in range of 50 to 80°C (122 to 176°F) during 10 minutes of driving.
Selector lever position
Expected problem location
“D” and “M” “R”
Stall speedHO
Forward brake
Forward one-way clutch
1st one-way clutch
3rd one-way clutch
OH
Reverse brake
LL
Engine and torque converter one-way clutch
HH
Line pressure low
Does not shift-up “D” or “M” position 1 → 2 Slipping in 2nd, 3rd or 4th gear Direct clutch slippage
Does not shift-up “D” or “M” position 2 → 3 Slipping in 3rd, 4th or 5th gear High and low reverse clutch slippage
Does not shift-up “D” or “M” position 3 → 4 Slipping in 4th or 5th gear Input clutch slippage
Does not shift-up “D” or “M” position 4 → 5 Slipping in 5th gear Front brake slippage
SCIA2187E