Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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).
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.