General Description and Operation

CONTROL SYSTEM DESCRIPTION
The RE4RO1A automatic transmission senses vehicle operating conditions through various sensors. It always controls the optimum shift position and reduces shifting and lock-up shocks.

FAIL-SAFE
The A/T control unit has an electronic Fail-Safe (limp home mode). This allows the vehicle to be driven even if a major electrical input/output device circuit is damaged. Under Fail-Safe, the vehicle always runs in third gear with shift lever position of 1, 2 or D. Customer may say "Sluggish, poor acceleration".
When Fail-Safe operation occurs the next time the key is turned to the "ON" position, the "OD OFF" indicator lamp will blink for about 8 seconds.
Fail-Safe may activate without electrical circuit damages if the vehicle is driven under extreme conditions (such as excessive wheel spins and emergency braking immediately afterwards). In this case, turn key "OFF" for 5 seconds and then "ON" to recover normal shift pattern.
The blinking of the "OD OFF" indicator lamp for about 8 seconds will appear only once and be cleared. The customer may resume normal driving conditions by chance. Always follow the "WORK FLOW" Chart.

The SELF-DIAGNOSIS results will be as follows:
- The first SELF-DIAGNOSIS will indicate the damage of the vehicle speed sensor or the revolution sensor.
- During the next SELF-DIAGNOSIS performed after checking the sensor, no damages will be indicated.

A/T CONTROL UNIT FUNCTION
The function of the A/T control unit is to:
- Receive input signals sent from various switches and sensors.
- Determine required line pressure, shifting point, lock-up operation, and engine brake operation.
- Send required output signals to the respective solenoids.




INPUT/OUTPUT SIGNAL OF A/T CONTROL UNIT