Fail-Safe Function

Fail-safe Function




- Front and rear vehicle speed sensors, rear wheel speed sensor abnormal
If a fault is detected in either or both of the front vehicle speed sensor and rear vehicle speed sensor, the vehicle speed information received from the ABS unit via CAN communication is substituted for control. This enables normal quality shifting.
- Inhibitor switch abnormal
If an input of other than the specified pattern is entered to the TCM, the select position indicator lights in the combination meter are turned off, the starter is disabled, the reverse light is disabled, the transmission is fixed in D range, and manual mode is inhibited.
- PN signal abnormal
The output is turned OFF (starter inhibited) if an abnormality is detected in the PN signal output. However, if the ECM is receiving range signals through the backup of CAN communication, the starter can be used in P and N ranges.
- AT interlock decision
If an AT interlock decision is made, the vehicle's minimum mobility is maintained by fixing the transmission in 2nd, 4th or 5th speeds in accordance with the engaging pattern detected by the hydraulic switch. Relation between the hydraulic switch detection pattern and fixed gear speeds are as shown in the table.
- Engine braking in 1st abnormal decision
If 1st engine braking abnormal decision is made, the low coast brake solenoid is deactivated to cancel the engine braking effect.
- Line pressure solenoid abnormal
The solenoid is deactivated and the line pressure set at maximum, 5th speed is inhibited. Except for this, the system is controlled normally.
- Lockup solenoid abnormal
The solenoid is deactivated and lockup is inhibited.
- Low coast brake solenoid abnormal
If the solenoid is failed and stuck in its ON state (electrically or mechanically) the transmission is fixed in 2nd speed, and when the solenoid is failed and stuck in its OFF state (electrically or mechanically) the solenoid is constantly turned OFF. (Engine braking is made not available in 1st and 2nd speeds.)
- Input clutch solenoid abnormal
If the solenoid is failed and stuck in its ON or OFF state (electrically or mechanically) the transmission is fixed in 4th speed to maintain mobility.
- Direct clutch solenoid abnormal
If the solenoid is failed and stuck in its ON or OFF state (electrically or mechanically) the transmission is fixed in 4th speed to maintain mobility.
- Front brake solenoid abnormal
If the solenoid is failed and stuck in its ON state (electrically or mechanically) the transmission is fixed in 5th speed, and when the solenoid is failed and stuck in its OFF state (electrically or mechanically) the transmission is fixed in 4th speed to maintain mobility.
- High and low reverse clutch solenoid abnormal
If the solenoid is failed and stuck in its ON or OFF state (electrically or mechanically) the transmission is fixed in 4th speed to maintain mobility.
- Transfer clutch solenoid abnormal
If the solenoid is failed and stuck in its ON or OFF state, the transfer solenoid output is constantly turned OFF.
- Turbine sensor 1, 2 abnormal
Shifting control is performed without using turbine sensor values to maintain minimum mobility. 5th speed and manual mode are inhibited.
- TCM data communication abnormal
If communication with the memory box on the control valves fails, backup values stored in the TCM are used for controlling the solenoids.
- CAN communication abnormal
If an abnormality occurs in CAN communication, data received via CAN communication are fixed to preset values to perform shift control and maintain minimum mobility. Lockup and manual mode are inhibited.