A6 Quattro Sedan V8-4.2L (BVJ) (2007)
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 high pressure components such as removing the high pressure pump, fuel rail, fuel injectors or fuel pipes, reduce the fuel
pressure in the high pressure area to approximately 6 bar. The procedure for this is as follows.
Special tools, testers and auxiliary items required
‹› Vehicle Diagnostic, Testing, and Information System (VAS 5051B)
High fuel pressure, reducing
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Connect Vehicle Diagnostic, Testing, and Information 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" read out.
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Select measured value block 140.
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With the engine running in idle, the fuel pressure will be displayed in display field 3.
‹› Specified value: between 35 and 45 bar
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Remove the right instrument panel cover..
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Remove the Fuel Pump Control Module (J538) fuse in the fuse panel with the engine idling.