Paseo Coupe L4-1497cc 1.5L DOHC MFI (1997)
Shift Solenoid: Description and Operation
SHIFT SOLENOIDS "A" AND "B" (No. 1 and No. 2)
CIRCUIT DESCRIPTION
The ECM uses signals from the vehicle speed sensor to detect the actual gear position (1st, 2nd, 3rd or O/D gear).The ECM then compares the
actual gear with the shift schedule in the ECM memory to detect mechanical trouble of the shift solenoid valves and valve body.
Shifting from 1st to O/D is done in combination with ON and OFF of the shift solenoid valves No.1 and No.2 controlled by ECM. If an open or
short circuit occurs in either of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valve to allow the vehicle to be
operated safely (Fail safe function).
Fail Safe Function
If either of the shift solenoid valve circuits develops an open or a short, the ECM turns the other shift solenoid ON and OFF to shift to the gear
positions shown in the table below. The ECM also turns the shift solenoid valve SL OFF at the same time. If both solenoids are malfunction,
hydraulic control cannot be done electronically so it must be done manually.
Manual shifting as shown in the following table must be done. (In the case of a short circuit, the ECM stops sending current to the short circuited
solenoid).
SHIFT SOLENOID "E" (SL)
CIRCUIT DESCRIPTION
The ECM uses the signals from the throttle position sensor, air-flow meter and crankshaft position sensor to monitor the engagement condition of
the lock-up clutch.
Then the ECM compares the engagement condition of the lock-up clutch with the lock-up schedule in the ECM memory to detect mechanical
trouble of the shift solenoid valve SL, valve body and torque converter clutch.
The shift solenoid valve SL is turned ON and OFF by signals from the ECM to control the hydraulic pressure acting on the lock-up relay valve,
which then controls operation of the lock-up clutch.
Fail safe Function
If the ECM detects a malfunction, it turns the shift solenoid valve SL OFF.
