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.
Performance Controls: Notes
Exhaust Flap: The 12.6 liter rear silencer (4) is fitted with an exhaust flap to keep noise to a minimum at engine idle speed and low RPM. The flap provides exhaust efficiency based on two effects:
- Minimization of the cross section (slight back pressure) and the outlet noise level at low exhaust flow rates
- Large cross-section with low backpressure at high speeds and loads
The exhaust flap is opened allowing additional flow when:
- The transmission gear is engaged and
- The engine speed is approximately above 1,500 RPM
A vacuum controlled diaphragm (2 - actuator mounted on the silencer) opens and closes the exhaust gas flap. The vacuum is supplied from the camshaft driven vacuum pump.
The exhaust flap is opened with vacuum, and is sprung closed by the actuator (when vacuum is not present). The procedure is carried out using a solenoid valve (1) which is electrically controlled by the ECM and located in the left rear luggage compartment (below the light assembly).
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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