Fail-Safe Function

WARNING: This page is about a different car, the 2009 Nissan Maxima. However, it is still accessible from the selected car via links, so may be relevant.

If any malfunction occurs in a sensor or solenoid valve, this function controls the CVT to make driving possible.

Output Speed Sensor (Secondary Speed Sensor)

The shift pattern is changed in accordance with the throttle position when an unexpected signal is sent from the output speed sensor (secondary speed sensor) to the TCM. The manual mode and "DS" mode are inhibited, and the transaxle is put in "D".

Input Speed Sensor (Primary Speed Sensor)

The shift pattern is changed in accordance with the throttle position and secondary speed (vehicle speed) when an unexpected signal is sent from the input speed sensor (primary speed sensor) to the TCM. The manual mode and "DS" mode are inhibited, and the transaxle is put in "D".

PNP Switch

If an unexpected signal is sent from the PNP switch to the TCM, the transaxle is put in "D".

CVT Fluid Temperature Sensor

If an unexpected signal is sent from the CVT fluid temperature sensor to the TCM, the gear ratio in use before receiving the unexpected signal is maintained or the gear ratio is controlled to keep engine speed under 5,000 RPM.

Transmission Fluid Pressure Sensor A (Secondary Pressure Sensor)

If an unexpected signal is sent from the transmission fluid pressure sensor A (secondary pressure sensor) to the TCM, the secondary pressure feedback control is stopped and the offset value obtained before the nonstandard condition occurs is used to control line pressure.
If transmission fluid pressure sensor A (secondary pressure sensor) error signal is inputted to the TCM, secondary pressure feedback control stops, but line pressure is controlled normally.

Pressure Control Solenoid A (Line Pressure Solenoid Valve)

If an unexpected signal is sent from the solenoid valve to the TCM, the pressure control solenoid A (line pressure solenoid valve) is turned OFF to achieve the maximum fluid pressure.

Pressure Control Solenoid B (Secondary Pressure Solenoid Valve)

If an unexpected signal is sent from the solenoid valve to the TCM, the pressure control solenoid B (secondary pressure solenoid valve) is turned OFF to achieve the maximum fluid pressure.

Torque Converter Clutch Solenoid Valve

If an unexpected signal is sent from the solenoid valve to the TCM, the torque converter clutch solenoid valve is turned OFF to cancel the lock up.

Step Motor

If an unexpected signal is sent from the step motor to the TCM, the step motor coil phases "A" through "D" are all turned OFF to hold the gear ratio used just before the non-standard condition occurred.

CVT Lock up Select Solenoid Valve

If an unexpected signal is sent from the solenoid valve to the TCM, the CVT lock up select solenoid valve 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 the TCM. Normal status is restored when turning the ignition switch OFF to ON after the normal power supply.