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.
EGR Valve
On 2002, 530i and 3.0Si, a dual diaphragm valve operates in 2 stages. When vacuum is about 3. in Hg, vacuum is applied to upper diaphragm to partially lift EGR valve from seat allowing a small amount of exhaust gas flow. The second stage of EGR valve is controlled by a vacuum control valve which senses absolute pressure in intake manifold. When second stage is opened, EGR vale is lifted completely off its seat allowing full exhaust gas recirculation.
On 630CSi, 633CSi and 733i, the EGR valve is controlled by vacuum inputs from the pressure transmitter and the electromagnetic switching valve or thermo valve. The EGR valve consists of two diaphragms which allows precise control of the quantity of exhaust gas recirculation. The upper diaphragm is sued to close the valve completely, thus stopping the flow of exhaust gas. The lower diaphragm determines the quantity of exhaust gas recirculation.
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.
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