Monitor Description

The torque converter lock-up is controlled by the ECM based on engine rpm, engine load, engine temperature, vehicle speed, transmission temperature, and shift range selection. The ECM determines the lock-up status of the torque converter by comparing the engine rpm (NE) to the input turbine rpm (NC0). The ECM calculates the actual transmission gear by comparing input turbine rpm (NC0) to output shaft rpm (SP2).

When conditions are appropriate, the ECM requests "lock-up" by applying control voltage to shift solenoid SL. When the SL is opened, solenoid SL applies pressure to the lock-up relay valve and locks the torque converter clutch. If the ECM detects an open or short in the SL solenoid circuit, the ECM interprets this as a fault in the SL solenoid or circuit. The ECM will turn on the MIL and store the DTC.