S5 Quattro Coupe V8-4.2L (CAUA) (2009)
Fuel Pressure Release: Service and Repair
Before Opening High Pressure Fuel Injection System
CAUTION!
The fuel injection system is separated into a high-pressure section (max. approximately 120 bar) and a low-pressure section
(approximately 6 bar).
Before opening any components under high pressure, the fuel pressure in the high pressure area must be reduced. The procedure for this
is as follows.
High fuel pressure, reducing:
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Connect Vehicle Diagnosis, testing & info. system (VAS 5051B).
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Start engine and run at idle speed.
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Select "engine electronics" in OBD.
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Then select "Measured values".
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Select "Fuel pressure" from the list.
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When the engine is at idle, fuel pressure between 30 and 40 bar is displayed.
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Pry off the cover - 1 - on the left of the instrument panel, for example using the Trim Removal Wedge (3409) - arrow -.