2003 NISSAN TEANA engine control

CVT SYSTEM
CVT-19
D
E
F
G
H
I
J
K
L
MA
B
CVT

CAN CommunicationBCS001G3
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-49,
"CAN System Specification Chart" .
Input/Output Signal of TCMBCS001G4
*1: Input by CAN communications.
*2: If these input and output signals are different, the TCM triggers the fail-safe function. Control item Fluid
pressure
control Select
control Shift con-
trol Lock-up
control CAN com-
munication
control Fail-safe
function
(*2)
Input PNP switch XXXXXX
Accelerator pedal position signal
(*1)XXXXXX
Closed throttle position signal
(*1)XXXX
Engine speed signal
(*1)XX XXX
CVT fluid temperature sensor X X X X X
Manual mode signal
(*1)XXXXX
Stop lamp switch signal
(*1)XXXX
Primary speed sensor X X X X X
Secondary speed sensor X X X X X X
Primary pressure sensor X X
Secondary pressure sensor X X X
TCM power supply voltage signal X X X X X X
Out-
put Step motor X X
TCC solenoid valve X X X
Lock-up select solenoid valve X X X
Line pressure solenoid valve X X X X
Secondary pressure solenoid valve X X X

CVT-20
CVT SYSTEM

Line Pressure and Secondary Pressure ControlBCS001G5

When an input torque signal equivalent to the engine drive force is sent from the ECM to the TCM, the
TCM controls the line pressure solenoid valve and secondary pressure solenoid valve.

This line pressure solenoid controls the pressure regulator valve as the signal pressure and adjusts the
pressure of the operating oil discharged from the oil pump to the line pressure most appropriate to the
driving state. Secondary pressure is controlled by decreasing line pressure.
NORMAL CONTROL
Optimize the line pressure and secondary pressure, depending on driving conditions, on the basis of the throt-
tle position, the engine speed, the primary pulley (input) revolution speed, the secondary pulley (output) revo-
lution speed, the brake signal, the PNP switch signal, the lock-up signal, the voltage, the target gear ratio, the
fluid temperature, and the fluid pressure.
FEEDBACK CONTROL
When controlling the normal fluid pressure or the selected fluid pressure, the secondary pressure can be set
more accurately by using the fluid pressure sensor to detect the secondary pressure and controlling the feed-
back.
Shift ControlBCS001G6
In order to select the gear ratio which can obtain the driving force in accordance with driver's intention and the
vehicle condition, TCM monitors the driving conditions, such as the vehicle speed and the throttle position and
selects the optimum gear ratio, and determines the gear change steps to the gear ratio. Then send the com-
mand to the step motor, and control the flow-in/flow-out of line pressure from the primary pulley to determine
the position of the moving-pulley and control the gear ratio.
SCIA1846E
SCIA6581E

CVT SYSTEM
CVT-21
D
E
F
G
H
I
J
K
L
MA
B
CVT

NOTE:
The gear ratio is set for every position separately.
“D” POSITION
Shifting over all the ranges of gear ratios from the lowest to the high-
est.
“M” POSITION
When the selector lever is put in the manual shift gate side, the fixed
changing gear line is set. By moving the selector lever to + side or -
side, the manual mode switch is changed over, and shift change like
M/T becomes possible following the changing gear set line step by
step.
DOWNHILL ENGINE BRAKE CONTROL (AUTO ENGINE BRAKE CONTROL)
When downhill is detected with the accelerator pedal released, the engine brake will be strengthened up by
downshifting so as not to accelerate the vehicle more than necessary.
ACCELERATION CONTROL
According to vehicle speed and a change of accelerator pedal angle, driver's request for acceleration and driv-
ing scene are judged. This function assists improvement in acceleration feeling by making the engine speed
proportionate to the vehicle speed. And a shift map which can gain a larger driving force is available for com-
patibility of mileage with drivability.
Lock-up and Select ControlBCS001G7

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. The torque converter clutch control valve engages or
releases the torque converter clutch piston.

When shifting between “N” (“P”) ⇔ “D” (“R”), torque converter clutch solenoid controls engagement power
of forward clutch and reverse brake.

The lock-up applied gear range was expanded by locking up the
torque converter at a lower vehicle speed than conventional
CVT models.
SCIA1953E
SCIA4582E
SCIA1958E

CVT-22
CVT SYSTEM

TORQUE CONVERTER CLUTCH AND SELECT CONTROL VALVE CONTROL
Lock-up and Select 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.
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.
Select Control
When shifting between “N” (“P”) ⇔ “D” (“R”), optimize the operating pressure on the basis of the throttle posi-
tion, the engine speed, and the secondary pulley (output) revolution speed to lessen the shift shock.
SCIA2374E

CVT-24
TROUBLE DIAGNOSIS

TROUBLE DIAGNOSISPFP:00004
DTC Inspection Priority ChartBCS001GE
If some DTCs are displayed at the same time, perform inspections one by one based on the following priority
chart.
NOTE:
If DTC “U1000 CAN COMM CIRCUIT” is displayed with other DTCs, first perform the trouble diagnosis
for “DTC U1000 CAN COMMUNICATION LINE”. Refer to CVT-53
.
Fail-safeBCS001GF
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.
FAIL-SAFE FUNCTION
If any malfunction occurs in a sensor or solenoid, this function controls the CVT to make driving possible.
Output Speed Sensor (Secondary Speed Sensor)
The shift pattern is changed in accordance with throttle position when an unexpected signal is sent from the
output speed sensor (secondary speed sensor) to the TCM. The manual mode position and second position is
inhibited, and the transaxle is put in “D”.
Input Speed Sensor (Primary Speed Sensor)
The shift pattern is changed in accordance with throttle position and secondary speed (vehicle speed) when
an unexpected signal is sent from the input speed sensor (primary speed sensor) to the TCM. The manual
mode position and second position is inhibited, and the transaxle is put in “D”.
PNP Switch
If an unexpected signal is sent from the PNP switch to the TCM, the transaxle is put in “D”.
Manual Mode Switch
If an unexpected signal is sent from the manual mode switch to the TCM, the transaxle is put in “D”.
CVT Fluid Temperature Sensor
If an unexpected signal is sent from the CVT fluid temperature sensor to the TCM, the gear ratio in use before
receiving the unexpected signal is maintained or the gear ratio is controlled to keep engine speed under 5,000
rpm.
Transmission Fluid Pressure Sensor A (Secondary Pressure Sensor)

If an unexpected signal is sent from the transmission fluid pressure sensor A (secondary pressure sensor)
to the TCM, the secondary pressure feedback control is stopped and the offset value obtained before the
non-standard condition occurs is used to control line pressure.

If transmission fluid pressure sensor A (secondary pressure sensor) error signal is input to TCM, second-
ary pressure feedback control stops, but line pressure is controlled normally.
Pressure Control Solenoid A (Line Pressure Solenoid)
If an unexpected signal is sent from the solenoid to the TCM, the pressure control solenoid A (line pressure
solenoid) is turned OFF to achieve the maximum fluid pressure.
Pressure Control Solenoid B (Secondary Pressure Solenoid)
If an unexpected signal is sent from the solenoid to the TCM, the pressure control solenoid B (secondary pres-
sure solenoid) is turned OFF to achieve the maximum fluid pressure.
Torque Converter Clutch Solenoid
If an unexpected signal is sent from the solenoid to the TCM, the torque converter clutch solenoid is turned
OFF to cancel the lock-up.
Priority Detected items (DTC)
1 U1000 CAN communication line
2 Except above

TROUBLE DIAGNOSIS
CVT-25
D
E
F
G
H
I
J
K
L
MA
B
CVT

Step Motor
If an unexpected signal is sent from the step motor to the TCM, the step motor coil phases “A” through “D” are
all turned OFF to hold the gear ratio used right before the non-standard condition occurred.
CVT Lock-up Select Solenoid
If an unexpected signal is sent from the solenoid to the TCM, the CVT lock-up select solenoid is turned OFF to
cancel the lock-up.
TCM Power Supply (Memory Back-up)
Transaxle assembly is protected by limiting the engine torque when the memory back-up power supply (for
controlling) from the battery is not supplied to TCM. Normal statues is restored when turning the ignition switch
OFF to ON after the normal power supply.
How to Perform Trouble Diagnosis for Quick and Accurate RepairBCS001GG
INTRODUCTION
The TCM receives a signal from the vehicle speed sensor, PNP
switch and provides shift control or lock-up control via CVT solenoid
valves.
Input and output signals must always be correct and stable in the
operation of the CVT system. The CVT system must be in good
operating condition and be free of valve seizure, solenoid valve mal-
function, etc.
It is much more difficult to diagnose an error that occurs intermit-
tently rather than continuously. Most intermittent errors are caused
by poor electric connections or improper wiring. In this case, careful
checking 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-II or a circuit tester connected should be performed.
Follow the CVT-26, "
WORK FLOW" .
Before undertaking actual checks, take a few minutes to talk with a
customer who approaches with a driveability complaint. The cus-
tomer can supply good information about such errors, especially
intermittent ones. Find out what symptoms are present and under
what conditions they occur. A “DIAGNOSTIC WORKSHEET” as
shown on the example (Refer to CVT-27
) should be used.
Start your diagnosis by looking for “conventional” errors first. This will
help troubleshoot driveability errors on an electronically controlled
engine vehicle.
Also check related Service bulletins.
SAT631IB
SAT632I
SEF234G

CVT-28
TROUBLE DIAGNOSIS

4❏ Perform road testCVT-35
4-1.Check before engine is started CVT-37
❏ CVT-164, "CVT Indicator Lamp Does Not Come On"
❏ Perform self-diagnosis. Enter checks for detected items. CVT-47
❏ CVT-53, "DTC U1000 CAN COMMUNICATION LINE"
❏ CVT-56, "DTC P0615 START SIGNAL CIRCUIT"
❏ CVT-60, "DTC P0703 STOP LAMP SWITCH CIRCUIT"
❏ CVT-62, "DTC P0705 PARK/NEUTRAL POSITION SWITCH"
❏ CVT-69, "DTC P0710 CVT FLUID TEMPERATURE SENSOR CIRCUIT"
❏ CVT-74, "DTC P0715 INPUT SPEED SENSOR CIRCUIT (PRI SPEED SENSOR)"
❏ CVT-79, "DTC P0720 VEHICLE SPEED SENSOR CVT (SECONDARY SPEED SEN-
SOR)"
❏ CVT-85, "DTC P0725 ENGINE SPEED SIGNAL"
❏ CVT-87, "DTC P0730 BELT DAMAGE"
❏ CVT-89, "DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE"
❏ CVT-94, "DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)"
❏ CVT-97, "DTC P0745 LINE PRESSURE SOLENOID VALVE"
❏ CVT-102, "DTC P0746 PRESSURE CONTROL SOLENOID A PERFORMANCE
(LINE PRESSURE SOLENOID VALVE)"
❏ CVT-105, "DTC P0776 PRESSURE CONTROL SOLENOID B PERFORMANCE
(SEC PRESSURE SOLENOID VALVE)"
❏ CVT-108, "DTC P0778 PRESSURE CONTROL SOLENOID B ELECTRICAL (SEC
PRESSURE SOLENOID VALVE)"
❏ CVT-113, "DTC P0826 MANUAL MODE SWITCH CIRCUIT"
❏ CVT-118, "DTC P0840 TRANSMISSION FLUID PRESSURE SENSOR A CIRCUIT
(SEC PRESSURE SENSOR)"
❏ CVT-123, "DTC P0841 PRESSURE SENSOR FUNCTION"
❏ CVT-126, "DTC P0845 TRANSMISSION FLUID PRESSURE SENSOR B CIRCUIT
(PRI PRESSURE SENSOR)"
❏ CVT-131, "DTC P0868 SECONDARY PRESSURE DOWN"
❏ CVT-134, "DTC P1701 TRANSMISSION CONTROL MODULE (POWER SUPPLY)"
❏ CVT-139, "DTC P1705 THROTTLE POSITION SENSOR"
❏ CVT-141, "DTC P1722 ESTM VEHICLE SPEED SIGNAL"
❏ CVT-143, "DTC P1723 CVT SPEED SENSOR FUNCTION"
❏ CVT-145, "DTC P1726 ELECTRIC THROTTLE CONTROL SYSTEM"
❏ CVT-147, "DTC P1740 LOCK-UP SELECT SOLENOID VALVE CIRCUIT"
❏ CVT-153, "DTC P1777 STEP MOTOR - CIRCUIT"
❏ CVT-157, "DTC P1778 STEP MOTOR - FUNCTION"
4-2.Check at idleCVT-37
❏ CVT-165, "Engine Cannot Be Started in “P” or “N” Position"
❏ CVT-166, "In “P” Position, Vehicle Moves Forward or Backward When Pushed"
❏ CVT-166, "In “N” Position, Vehicle Moves"
❏ CVT-167, "Large Shock “N” → “R” Position"
❏ CVT-168, "Vehicle Does Not Creep Backward in “R” Position"
❏ CVT-169, "Vehicle Does Not Creep Forward in “D” Position"

TROUBLE DIAGNOSIS
CVT-29
D
E
F
G
H
I
J
K
L
MA
B
CVT

44-3.Cruise testCVT-38
❏ CVT-170, "CVT Does Not Shift"
❏ CVT-171, "Cannot Be Changed to Manual Mode"
❏ CVT-171, "CVT Does Not Shift in Manual Mode"
❏ CVT-172, "Vehicle Does Not Decelerate by Engine Brake"
❏ Perform self-diagnosis. Enter checks for detected items. CVT-47
❏ CVT-53, "DTC U1000 CAN COMMUNICATION LINE"
❏ CVT-56, "DTC P0615 START SIGNAL CIRCUIT"
❏ CVT-60, "DTC P0703 STOP LAMP SWITCH CIRCUIT"
❏ CVT-62, "DTC P0705 PARK/NEUTRAL POSITION SWITCH"
❏ CVT-69, "DTC P0710 CVT FLUID TEMPERATURE SENSOR CIRCUIT"
❏ CVT-74, "DTC P0715 INPUT SPEED SENSOR CIRCUIT (PRI SPEED SENSOR)"
❏ CVT-79, "DTC P0720 VEHICLE SPEED SENSOR CVT (SECONDARY SPEED SEN-
SOR)"
❏ CVT-85, "DTC P0725 ENGINE SPEED SIGNAL"
❏ CVT-87, "DTC P0730 BELT DAMAGE"
❏ CVT-89, "DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE"
❏ CVT-94, "DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)"
❏ CVT-97, "DTC P0745 LINE PRESSURE SOLENOID VALVE"
❏ CVT-102, "DTC P0746 PRESSURE CONTROL SOLENOID A PERFORMANCE
(LINE PRESSURE SOLENOID VALVE)"
❏ CVT-105, "DTC P0776 PRESSURE CONTROL SOLENOID B PERFORMANCE
(SEC PRESSURE SOLENOID VALVE)"
❏ CVT-108, "DTC P0778 PRESSURE CONTROL SOLENOID B ELECTRICAL (SEC
PRESSURE SOLENOID VALVE)"
❏ CVT-113, "DTC P0826 MANUAL MODE SWITCH CIRCUIT"
❏ CVT-118, "DTC P0840 TRANSMISSION FLUID PRESSURE SENSOR A CIRCUIT
(SEC PRESSURE SENSOR)"
❏ CVT-123, "DTC P0841 PRESSURE SENSOR FUNCTION"
❏ CVT-126, "DTC P0845 TRANSMISSION FLUID PRESSURE SENSOR B CIRCUIT
(PRI PRESSURE SENSOR)"
❏ CVT-131, "DTC P0868 SECONDARY PRESSURE DOWN"
❏ CVT-134, "DTC P1701 TRANSMISSION CONTROL MODULE (POWER SUPPLY)"
❏ CVT-139, "DTC P1705 THROTTLE POSITION SENSOR"
❏ CVT-141, "DTC P1722 ESTM VEHICLE SPEED SIGNAL"
❏ CVT-143, "DTC P1723 CVT SPEED SENSOR FUNCTION"
❏ CVT-145, "DTC P1726 ELECTRIC THROTTLE CONTROL SYSTEM"
❏ CVT-147, "DTC P1740 LOCK-UP SELECT SOLENOID VALVE CIRCUIT"
❏ CVT-153, "DTC P1777 STEP MOTOR - CIRCUIT"
❏ CVT-157, "DTC P1778 STEP MOTOR - FUNCTION"
5❏ Inspect each system for items found to be NG in the self-diagnosis and repair or replace the malfunctioning parts
6❏ Perform all road tests and enter the checks again for the required itemsCVT-35
7❏ For any remaining NG items, perform the “diagnosis procedure” and repair or replace the malfunctioning parts
8❏ Erase the results of the self-diagnosis from the TCMCVT-49