Troubleshooting

DTC P0741 Torque Converter Clutch Solenoid Performance (Shift Solenoid Valve SL)

SYSTEM DESCRIPTION

DTC Detecting Condition:

The ECM uses the signals from the throttle position sensor, air-flow meter and crankshaft position sensor to monitor the engagement condition of the lock-up clutch.

Then the ECM compares the engagement condition of the lock-up clutch with the lock-up schedule in the ECM memory to detect mechanical trouble of the shift solenoid valve SL, valve body, torque converter clutch or automatic transaxle (clutch, brake, gear etc.).

MONITOR DESCRIPTION

Monitor Strategy:

Typical Enabling Conditions:

Typical Malfunction Thresholds:

Torque converter lock-up is controlled by the ECM based on 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) with the input turbine rpm (NT). The ECM calculates the actual transmission gear by comparing input turbine rpm (NT) with the counter gear rpm (NC) and output shaft rpm (NO). When conditions are appropriate, the ECM requests "lock-up" by applying control voltage to shift solenoid SL. When the SL is turned on, solenoid SL 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. The ECM will turn on the MIL and store the DTC.

Example:
When any of the following is met, the system judges it as a malfunction.
a. There is a difference in rotation between before and after torque converters even when the ECM commands lock-up.
(Engine speed is at least 130 rpm greater than input speed.)

b. There is no difference in rotation between before and after torque converters even when the ECM commands lock-up off.
(The difference between engine speed and input speed is less than 35 rpm.)

Step 1 - 3:

INSPECTION PROCEDURE