Engine Load Speed Change Estimate Control

To prevent major loads from changing engine speed significantly, the ECU monitors signals from the Neutral Start Switch (NSW) and the Air Conditioner switch (A/C) and re-establishes target idle speeds accordingly. ISCV position is adjusted very quickly as the status of the A/C or NSW inputs change. Before a change in engine speed can occur, the ECU has moved the ISCV to compensate for the change in engine load. This feature helps to maintain a stable idle speed under changing load conditions.

The following chart shows typical target idle speeds which can be found in New Car Feature books. These speed specifications can be useful when troubleshooting suspected operational problems in the step type idle speed control system or related input sensor circuits.

7M-GE Stepper Type ISC Target Idle Speeds (Warm Engine)

A/C Switch Position

Neutral/Start Switch Position

Target Idle Speed

ON

ON

900 rpm

ON

OFF

750 rpm

ON

M/T

900 rpm

OFF

ON

700 rpm

OFF

OFF

600 rpm

OFF

M/T

700 rpm

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