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.
Auxiliary Air Valve
The 924S and 944 (except 944S) use an auxiliary air valve to provide additional air during cold engine starts and warm-up. It is located next to throttle body. The valve consists of an electrically heated bi-metallic strip, movable disc and air by-pass channel. The heater coil on the bi-metallic strip is energized by the fuel pump relay.
Control of the valve is based upon engine temperature. The air by-pass channel is open when engine is cold and gradually closes as temperature rises. At predetermined temperatures, air by-pass channel is blocked and additional airflow stops.
Use the Manual With the Right Hardware
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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.