CVT-34< SERVICE INFORMATION >
[RE0F08A]
TROUBLE DIAGNOSIS
If an unexpected signal is sent from the solenoid to t he 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 Repair INFOID:0000000004666882
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.
The TCM also communicates with the ECM by means of a signal
sent from sensing elements used wit h the OBD-related parts of the
CVT system for malfunction-diagnostic 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 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. Mo st intermittent errors are caused
by poor electric connections or improper wiring. In this case, careful
checking of suspected circuits ma y 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" .
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 "Diagnostic Worksheet Chart" )
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.
WORK FLOW
A good understanding of the malfunction conditions can make troubleshooting faster and more accurate.
In general, each customer feels differently about a malf unction. It is important to fully understand the symp-
toms or conditions for a customer complaint.
Make good use of the two sheets provided, "Informati on From Customer" and "Diagnostic Worksheet Chart" ,
to perform the best troubleshooting possible.
Work Flow Chart SAT631IB
SAT632I
SEF234G
TROUBLE DIAGNOSIS
CVT-41
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• Inspect for fluid leakage and check the fluid level. Refer to
CVT-17, " Checking CVT Fluid " .
Fluid Condition Check Inspect the fluid condition.
STALL TEST
Stall Test Procedure 1. Inspect the amount of engine oil. Replenish the engine oil if necessary.
2. Drive for about 10 minutes to warm up the vehicle so that the CVT fluid temperature is 50 to 80 °C (122 to 176 °F). Inspect the
amount of CVT fluid. Replenish if necessary.
3. Securely engage the parking brake so that the tires do not turn.
4. Install a tachometer where it can be seen by driver during test. •It is good practice to mark the point of specified engine
rpm on indicator.
5. Start engine, apply foot brake, and place selector lever in “D” position.Fluid status Conceivable cause Required operation
Varnished (viscous
varnish state) Clutch, brake
scorched Replace the CVT fluid and check the
CVT main unit and the vehicle for
malfunctions (wire harnesses, cool-
er pipes, etc.)
Milky white or
cloudy Water in the fluidReplace the CVT fluid and check for
places where water is getting in.
Large amount of
metal powder mixed
in Unusual wear of
sliding parts within
CVT Replace the CVT fluid and check for
improper operation of the CVT. SAT638A
SAT647B
SAT513G
SAT775B
CVT-42< SERVICE INFORMATION >
[RE0F08A]
TROUBLE DIAGNOSIS
6. While holding down the foot brake, gradually press down the accelerator pedal.
7. Quickly read off the stall speed, and then quickly remove your foot from the accelerator pedal.
CAUTION:
Do not hold down the accelerator pedal for more than 5 sec-
onds during this test.
8. Move the selector lever to the “N” position.
9. Cool down the CVT fluid. CAUTION:
Run the engine at idle for at least 1 minute.
10. Repeat steps 6 through 9 with selector lever in “R” position.
Judgement Stall Test
O: Stall speed within standard value position.
H: Stall speed is higher than standard value.
L: Stall speed is lower than standard value.
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 CVT fluid reaches in the range of 50 to 80°C
(122 to 176 °F), then inspect the amount of CVT fluid and replenish if necessary.
NOTE: Stall speed: 2,600 - 3,150 rpm SAT514G
SAT771B
Selector lever position
Expected problem location
“D” “R”
Stall rotation H O • Forward clutch
O H • Reverse brake L L • Engine and torque converter one-way clutch
H H • Line pressure low
• Primary pulley
• Secondary pulley
• Steel belt SCIA6184E
CVT
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The CVT fluid temperature rises in the range of 50 - 80
°C (122 - 176 °F) during 10 minutes of driving.
3. After warming up CVT, remove the oil pressure detection plug and install the oil pressure gauge [special service tool: - (OTC3492)].
CAUTION:
When using the oil pressure gauge, be sure to use the O-ring attached to the oil pressure detec-
tion plug.
4. Securely engage the parking brake so that the tires do not turn.
5. Start the engine, and then measure the line pressure at both idle and the stall speed.
CAUTION:
• Keep the brake pedal pressed all the way down during
measurement.
• When measuring the line pressure at the stall speed, refer
to "STALL TEST" .
6. After the measurements are complete, install the oil pressure detection plug and tighten to the specified torque below.
CAUTION:
• Do not reuse O-ring.
• Apply CVT fluid to O-ring.
Line Pressure
*: Reference values
Judgement of Line Pressure Test
CVT-44< SERVICE INFORMATION >
[RE0F08A]
TROUBLE DIAGNOSIS
Road Test INFOID:0000000004666886
DESCRIPTION
• The purpose of the test is to determine overall performance of CVT and analyze causes of problems.
• The road test consists of the following three parts:
1. “Check Before Engine Is Started” CVT-45 .
2. “Check at Idle” CVT-45 .
3. “Cruise Test” CVT-47 .
Judgement Possible cause
Idle speed Low for all positions
(“P”, “R”, “N”, “D”, “L”) 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 specific
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
function.
For example
• Accelerator pedal position signal malfunction
• CVT fluid temperature sensor malfunction
• Pressure control solenoid A (line pressure solenoid) malfunction (sticking in OFF state, filter
clog, cut line)
• Pressure regulator valve or plug sticking
Stall speed Line pressure does
not rise higher than
the line pressure for
idle. Possible causes include a sensor malfunction or malfunction in the pressure adjustment func-
tion.
For example
• Accelerator pedal position signal malfunction
• TCM malfunction
• Pressure control solenoid A (line pressure solenoid) malfunction (shorting, sticking in ON state)
• Pressure regulator valve or plug sticking
The pressure rises,
but does not enter the
standard position. Possible causes include malfunctions in the pressure supply system and malfunction in the pres-
sure adjustment function.
For example
• Accelerator pedal position signal malfunction
• Pressure control solenoid A (line pressure solenoid) malfunction (sticking, filter clog)
• Pressure regulator valve or plug sticking
Only low for a specific
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. SAT786A
TROUBLE DIAGNOSIS
CVT-45
< SERVICE INFORMATION >
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• Before road test, familiarize yourself with all test procedures and
items to check.
• Perform tests on all items until specified symptom is found. Trou-
bleshoot items which check out No Good after road test.
CONSULT-III START PROCEDURE • Using CONSULT-III, perform a cruise test and record the result.
• Print the result and ensure that shifts and lock-ups take place as per Shift Schedule.
1. Touch “DATA MONITOR” on “SELECT DIAG MODE” screen.
2. Touch “MAIN SIGNALS” to set recording condition.
3. See “Numerical Display”, “Barchart Display” or “Line Graph Display”.
4. Touch “START”.
5. When performing cruise test. Refer to CVT-47, " Cruise Test " .
6. After finishing cruise test part, touch “RECORD”.
7. Touch “STORE”.
8. Touch “BACK”.
9. Touch “DISPLAY”.
10. Touch “PRINT”.
11. Check the monitor data printed out.
Check before Engi ne Is Started INFOID:00000000046668871.
CHECK O/D OFF INDICATOR LAMP
1. Park vehicle on flat surface.
2. Move selector lever to “P” position.
3. Turn ignition switch OFF. Wait at least 5 seconds.
4. Turn ignition switch ON. (Do not start engine.)
Does O/D OFF indicator lamp come on for about 2 seconds? YES >> 1. Turn ignition switch OFF.
2. Perform self-diagnosis and note NG items.Refer to CVT-51, " CONSULT-III Function (TRANSMISSION) " .
3. Go to CVT-45, " Check at Idle " .
NO >> Stop “Road Test”. Go to CVT-155, " O/D OFF Indicator Lamp Does Not Come On " .
Check at Idle INFOID:00000000046668881.
CHECK STARTING THE ENGINE
1. Park vehicle on flat surface.
2. Move selector lever to “P” or “N” position.
3. Turn ignition switch OFF.
4. Turn ignition switch START.
Is engine started? SAT496G
TROUBLE DIAGNOSIS
CVT-49
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CHECK ENGINE BRAKE FUNCTION — PART 3
1. Move selector lever to “L” position.
2. Check engine brake.
Does engine braking effectively reduce speed in “ L ” position?
YES >> 1. Stop the vehicle.
2. Perform self-diagnosis. Refer to CVT-51, " CONSULT-III Function (TRANSMISSION) " .
NO >> Mark the box of CVT-163, " Vehicle Does Not Decelerate by Engine Brake " on the
CVT-34, " How
to Perform Trouble Diagnosis for Quick and Accurate Repair " . Then continue trouble diagnosis.
Vehicle Speed When Shifting Gears INFOID:0000000004666890
Numerical value data are reference values.
CAUTION:
Lock-up clutch is engaged when vehi cle speed is approximately 18 km/h (11 MPH) to 90 km/h (56 MPH).
TCM Terminal and Reference Value INFOID:0000000004666891
TCM HARNESS CONNECTOR TERMINAL LAYOUT
TERMINALS AND REFERENCE VALUES FOR TCM Data are reference values and are measured between each terminal and ground.
Engine type Throttle position Shift pattern
Engine speed (rpm)
At 40 km/h (25 MPH) At 60 km/h (37 MPH)
MR18DE 8/8
“D” position
Overdrive-off mode “L” position 3,600 - 4,500 4,400 - 5,300
2/8 “D” position 1,300 - 3,100 1,400 - 3,500
Overdrive-off mode 2,200 - 3,000 2,800 - 3,600 “L” position 3,200 - 4,100 3,900 - 4,800 WCIA0717E
Terminal
Wire
color Item Condition Data (Approx.)
1 GR Pressure control
solenoid valve A
(Line pressure
solenoid valve)
and Release your foot from the accelerator pedal. 5.0 - 7.0 V
Press the accelerator pedal all the way down. 1.0 - 3.0 V
2 LG Pressure control
solenoid valve B
(Secondary
pressure sole-
noid valve) Release your foot from the accelerator pedal. 5.0 - 7.0 V
Press the accelerator pedal all the way down. 3.0 - 4.0 V
3 SB Torque converter
clutch solenoid
valve When vehi-
cle cruises in
“D” position. When CVT performs lock-up. 6.0 V
When CVT does not perform lock-up. 1.0 V
DTC P0710 CVT FLUID TEMP
ERATURE SENSOR CIRCUIT
CVT-79
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3. Check resistance between CVT unit harness connector termi-
nals.
4. If NG, replace the transaxle assembly. Refer to CVT-182," Removal and Installation " .
Name Connector Terminal
Tempera-
ture °C ( °F) Resistance
(Approx.)
CVT fluid
temperature
sensor F46 17 - 19 20 (68) 6.5 k
Ω
80 (176) 0.9 k Ω SCIA4679E