Monitor Description

WARNING: This page is about a different car, the 2010 Toyota Camry. However, it is still accessible from the selected car via links, so may be relevant.

Torque converter lock-up is controlled by the TCM based on the turbine (input) speed sensor NT, output speed sensor NC, engine RPM, engine load, engine temperature, vehicle speed, transmission fluid temperature, and gear selection. The TCM determines the lock-up status of the torque converter by comparing the engine RPM (NE) to the input turbine RPM (NT). The TCM calculates the actual transmission gear by comparing input turbine RPM (NT) to output shaft RPM (NC). When conditions are appropriate, the TCM requests "lock-up" by applying control voltage to shift solenoid SLU. When SLU is turned on, it applies pressure to the lock-up relay valve and locks the torque converter clutch.

If the TCM detects no lock-up after lock-up has been requested or if it detects lock-up when it is not requested, the TCM interprets this as a fault in shift solenoid valve SLU or lock-up system performance.

The TCM will turn on the MIL and store the DTC.

Example:

When any of the following is met, the system judges it as a malfunction.

There is a difference in rotation (speed) between the input side (engine speed) and output side (input turbine speed) of the torque converter when the TCM commands lock-up.
(Engine speed is at least 70 RPM greater than input turbine speed.)
There is no difference in rotation (speed) between the input side (engine speed) and output side (input turbine speed) of the torque converter when the TCM commands lock-up off.
(The difference between engine speed and input turbine speed is less than 20 rpm.)