Fail-Safe Chart

This function minimizes the loss of the ECT functions when any malfunction occurs in each sensor or solenoid.

1. ATF (Automatic Transmission Fluid) temperature sensor:

   When the ATF temperature sensor has a malfunction, O/D upshift is prohibited.

2. Counter gear speed sensor NC (Speed sensor NC):

   When the counter gear speed sensor has a malfunction, O/D upshift is prohibited.

3. Shift solenoid valve DSL:

   When the solenoid valve DSL has a malfunction, the current to the solenoid valve is stopped. This stops lock up control, then fuel economy decreases.

4. Shift solenoid valve SL1, SL2 and S4:

   Fail safe function:

   If either of the shift solenoid valve circuits develops an open or short, the ECM turns the other shift solenoid "ON" and "OFF" in order to shift into the gear positions shown in the table below.

   Manual shifting as shown in the following table must be done (In case of a short circuit, the ECM stops sending the current to the short circuit solenoid).

   Even if starting the engine in the fail-safe mode, the gear position remain in the same position.

   Fig 1: Fail Safe Function Chart (1 Of 2)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   Fig 2: Fail Safe Function Chart (2 Of 2)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002