Operation and Drive, Torque Reduction

DRIVE
When selector lever on a car with automatic transmission is moved to a position other than P or N, Batt+ is applied to pin 14 of the Trionic ECM. The ECM is then programmed for automatic transmission and opens the idle air control valve slightly more to compensate for the rise in load. Pin 14 is not connected on cars with manual transmission.

If a gear position other than P or N is selected, a temporary reduction in ignition depending on throttle position takes place in order to protect the automatic transmission.

Torque Reduction
The automatic transmission control module grounds pin 13 of the Trionic ECM on gear-changing. The Trionic system then retards ignition to make gear-changing smoother and protect the automatic transmission.

During gear-changing, the ignition timing is between 17° BTDC and 10° ATDC, depending on engine speed and load.

Reduced Boost Pressure
The ECM reduces the boost pressure on cars with automatic transmission.

If there is a fault in the circuit to pins 13 or 14, gear-changing becomes less smooth and the automatic transmission may be damaged.

Brake
If both the brake peal and accelerator pedal are depressed and engine speed is less than 3000 rpm, ignition reduction occurs. The purpose of this is to protect the automatic transmission in the event of "stalling".