Intake (Vacuum) Jet Pump
The intake jet pump function is controlled by the MS42 ECM. The purpose is to provide sufficient vacuum for the brake booster in all operating conditions.
The additional vacuum compensation is activated by the ECM when the idle speed actuator is regulated for:
- A/C compressor "ON"
- Drive gear engaged (if the transmissions in fail-safe, the jet pump will always be operating)
- Engine warm up <70°C
The ECM controls the Intake Jet Pump by activating the Solenoid Control Valve. Additional Vacuum Enhancement is applied to the brake booster when the control circuit is "deactivated" (solenoid sprung open). Vacuum Enhancement is limited to the brake booster when the control circuit is "activated" (solenoid powered closed).