Description
The ecm uses the signals from the throttle position sensor, air-flow meter, turbine (input) speed sensor, intermediate (counter) shaft speed sensor and crankshaft position sensor to monitor the engagement condition of the lock-up clutch.
Then the ecm compares the engagement conditions of the lock-up clutch with the lock-up schedule in the ecm memory to detect mechanical problems of the shift solenoid valve dsl, valve body and torque converter clutch.
Monitor description
Torque converter lock-up is controlled by the ecm based on the speed sensor (nt), speed sensor (nc), engine rpm, engine load, engine temperature, vehicle speed, transmission temperature and gear selection.
The ecm determines the lock-up status of the torque converter by comparing the engine rpm (ne) to the input turbine rpm (nt). The ecm calculates the actual transmission gear by comparing input turbine rpm control voltage to counter gear rpm (nc). When conditions are appropriate, the ecm requests "lock-up" by applying control voltage to the shift solenoid valve dsl. When the dsl is turned on, it applies pressure to the lock-up relay valve and locks the torque converter clutch.
If the ecm detects no lock-up after lock-up has been requested or if it detects lock-up when it is not requested, the ecm interprets this as a fault in the shift solenoid valve dsl or lock-up system performance.
The ecm will illuminate the mil and store the dtc.
Example:
When any of the following is met, the system judges it as a malfunction.
(Engine speed is at least 100 rpm greater than input turbine speed.)
(The difference between engine speed and input turbine speed is less than 35 rpm.)
Monitor strategy
Typical enabling conditions
Typical malfunction thresholds
Either of the following conditions is met: off malfunction or on malfunction
Off malfunction
On malfunction
2 Detections are necessary per driving cycle:
1St detection: temporary flag on
2Nd detection: pending fault code on
Vehicle speed must be under 10 km/h (6.2 Mph) once before 2nd detection
Wiring diagram
Inspection procedure
Hint:
Performing the intelligent tester's active test allows relay, vsv, actuator and other items to be operated without removing any parts. Performing the active test early in troubleshooting is one way to save time.
The data list can be displayed during the active test.
Hint:
Hint:
Result
Hint:
If any other codes besides p0741 are output, perform troubleshooting for those dtcs first.
Standard resistance
Standard resistance
Replace ecm
Standard resistance: 11 to 13 ùat 20°c (68°f)
Ok: valve moves and makes operating noise.
Ok: the connectors and pins are securely installed.
There is no open or short on the wire harness.
Ok: there are no foreign objects on each valve.
Ok: the torque converter clutch operates normally.
Repair automatic transaxle assembly
Suspension system
Problem symptoms table
Hint:
Use the table below to help determine the cause of the
problem symptom. The potential causes of the symptoms are
listed in order of probability in the "suspected area" column of
the table. Check each symptom by checking the suspected
areas in the order th ...
Freeze frame data
Description
Freeze frame data records the engine conditions (fuel
system, calculated load, engine coolant temperature,
fuel trim, engine speed, vehicle speed, etc.) When a
malfunction is detected. When troubleshooting, it can
help determine if the vehicle was running or stopped, the
engin ...
Key lock-in prevention function does not work properly
Description
When the key is in the ignition key cylinder or the door courtesy light on
signal is output to the main body
ecu, performing the door lock operation with the lock switch does not lock the
door.
Wiring diagram
Inspection procedure
Read value of intelligent tester (unlock w ...