Reducing pressure in high-pressure section of injection system |
WARNING The fuel system operates at extremely high pressure. This can cause injury. |
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| The injection system consists of a high-pressure section (maximum approx. 200 bar) and a low-pressure section (approx. 7 bar). |
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| Prior to opening the high-pressure section (e.g. when removing the high-pressure pump, fuel rail, injectors, fuel pipes or fuel pressure sender -G247-), the fuel pressure in the high-pressure section must be reduced to a specified level. The procedure is described below. |
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Reducing fuel pressure in high-pressure section: |
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| Connect → Vehicle diagnostic tester, select function „Reducing fuel pressure in fuel rail“ in „Guided Functions“ and follow on-screen instructions. |
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| Fuel pressure will drop to a specified value. |
The fuel rail is still filled with fuel, however it is no longer under high pressure. |
WARNING There is a risk of injury: avoid skin contact with fuel. |
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| Wear safety goggles and protective clothing when opening the fuel system. |
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| Before opening the high-pressure section of the fuel system, place a clean cloth around the connection to catch escaping fuel. |
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| The high-pressure system must be opened »immediately« after reducing the fuel pressure; wrap a clean cloth around the connection. Catch the escaping fuel. |
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| The pressure will increase again due to the effect of residual heat if the high-pressure system is not opened immediately. |
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| The ignition must not be switched on again from this point on as this would increase the pressure again. |
Additional steps required |
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| Erase event memory and generate readiness code in engine control unit in „Guided Functions“ mode. |
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