Serena 2 (1999-2005)

Automatic transmission fault diagnostics — system description (Nissan Serena C24)

Table of contents: Operation of the automatic…↓ Vehicle speed sensor 1 (secondary…↓ Accelerator sensor ↓ Range switch ↓ Switch solenoids A and B ↓ Line pressure control solenoid ↓ Torque Converter Clutch Lockup…↓ Engine Brake Clutch Solenoid ↓ Automatic transmission control…↓

Operation of the automatic transmission in emergency mode

When the vehicle is moving, if malfunctions occur in the sensors and solenoids listed below, the automatic transmission may switch to emergency mode.

Vehicle speed sensor 1 (secondary shaft speed sensor automatic transmission)

If this sensor fails, its signal is replaced by the signal from vehicle speed sensor 2 for the instrument cluster.

Accelerator sensor

If this sensor fails, the control unit uses signals from the idle switch and the full accelerator pedal switch and sets the degree of pressure on the accelerator pedal and the pressure in the line, see table.

Range switch

If the automatic transmission control unit receives two or more signals from the range switch, the control unit selects one of the positions D, N, R, 2 and 1 depending on the priority determined inside the unit. However, when returning to normal operation, switching to 4th gear is blocked. In addition, depending on the state in the range switch valve circuit, the current driving state of the vehicle is determined as shown in the table.

Switch solenoids A and B

If the transmission control unit receives an abnormal signal from the solenoid, gear shifting occurs as follows:

A: Solenoid ON.
X: Solenoid OFF.
-: Abnormal signal

Line pressure control solenoid

If the automatic transmission control unit receives an abnormal signal from the solenoid, the solenoid is switched off and a maximum line pressure signal is set.

Torque Converter Clutch Lockup Solenoid

If the automatic transmission control unit receives an abnormal signal from the solenoid, the solenoid is switched off and the torque converter lock-up is released.

Engine Brake Clutch Solenoid

If the solenoid sends an abnormal signal to the automatic transmission control unit, the solenoid will be switched off. During deceleration, engine braking will occur.