Idle Speed Control (ISC)

3S-FE, 3S-GE, 5M-GE, 7M-GE & 7M-GTE Engines

Idle speed is electronically controlled to compensate for engine operating conditions such as cold engine operation and heavy accessory loads. Idle speed is controlled by air flow through a throttle bypass port, which in turn is controlled by a solenoid operated valve. The ECU is programmed with target idle speed values for specific operating conditions, and maintains idle speed within these target values by controlling operation of the throttle bypass solenoid valve.