CVT SYSTEM
CVT-207
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Lock-up and Se
lect Control INFOID:0000000004305581
• The torque converter clutch piston in the torque conv erter 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.
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 (out put) revolution speed to lessen the shift shock.
Control Valve INFOID:0000000004305582
FUNCTION OF CONTROL VALVE SCIA1958E
SCIA2374E
ON BOARD DIAGNOSTIC (OBD) SYSTEM
CVT-211
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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-20, " Schematic " , or see
EC-1532, " Wiring Diagram " .
2. When the engine is start ed, the MIL should go off.
If the MIL remains on, the on board diagnostic system has
detected an engine system malfunction. SEF217U
TROUBLE DIAGNOSIS
CVT-213
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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:0000000004305590
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-diagnos tic 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. Most intermittent errors are caused
by poor electric connections or impr oper wiring. In this case, careful
checking of suspected circuits may help prevent the replacement of
good parts.
A visual check only may not find t he 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
CVT-214< SERVICE INFORMATION >
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TROUBLE DIAGNOSIS
DIAGNOSTIC WORKSHEET
Information From Customer
KEY POINTS
• WHAT ..... Vehicle & CVT model
• WHEN ..... Date, Frequencies
• WHERE ..... Road conditions
• HOW ..... Operating conditions, Symptoms
*1. "Information From Customer" *2. "DIAGNOSTIC WORKSHEET" *3.
CVT-212*4.
CVT-219 *5.
CVT-219 ,
CVT-219 *6.
CVT-223 *7.
CVT-230 *8.
CVT-209 *9.
CVT-212 *10.
CVT-238 *11.
CVT-315 *12.
CVT-323 *13.
CVT-209 *14.
CVT-238 *15.
CVT-315 *16.
EC-1052 AWDIA0189G B