Checking Fuel Pressure
- Wear personal protective gear when working with fuel.
- In case of contact with skin or eyes wash immediately with plenty of warm water and acid-free soap.
- Consult a doctor as soon as possible.
- Danger of fire or explosion
→ Avoid contact with hot parts or sources of ignition.
→ Use suction to remove ignitable vapours.
→ Attach warning sign in a clearly visible position.
→ Contain leaked media using non-flammable absorbent material and put it in a container designed for this purpose for disposal in accordance with local requirements.
→ Secure collection containers/vessels to prevent them from tipping over.
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- The battery voltage must not fall below 12.5 volts during the delivery rate/pressure check.
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- There is no need to create a Vehicle Analysis Log (VAL).
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- The fuel pressure in the low-pressure system can also be read out using the PIWIS Tester.
- > P378a - Pressure gauge
> Fuel pressure test tool
with connecting line must be connected to the fuel line.
Fuel pressure test tool
- Check fuel pressure.
Connect the PIWIS Tester to the vehicle and switch on the PIWIS Tester .
Switch on the ignition.
Start diagnostics.
Select "DIME" control unit.
Select the "Drive links/checks " tab.
Select "Drain tank" .
Select the "Drain fuel tank" sub-procedure and press F12 to continue.
Follow the instructions on the Tester.
- Read off the pressure value on the pressure gauge (Important: The relative pressure is displayed = setpoint value
).
Check fuel pressure:
Setpoint value C2
> Absolute fuel pressure 6 bar +/- 0.2 bar
Setpoint value for all-wheel drive vehicles
> Absolute fuel pressure 6.2 bar +/- 0.2 bar
- Check holding pressure.
Read off the pressure on the pressure gauge after 20 minutes.
> Pressure 4.0 bar +/- 0.2 bar
> Pressure 4.0 bar +/- 0.2 bar
- To be on the safe side and as a check, the fuel pressure can also be read out as absolute pressure (relative pressure + 1 bar)
on the PIWIS Tester
using the following path:
Select "DIE" control unit.
Select the "Actual values/input signals" tab.
Select the menu item "B_Fuel system" and press F12 to continue.
Select the sub-procedure "B220_Fuel low pressure actual value" and press F12 to continue.
Follow the instructions on the Tester.
- Check fuel pressure:
Location Description Type Basic value Tolerance PIWIS Tester fuel pressure display Setpoint value C2 Absolute fuel pressure 6 bar +/- 0.2 bar PIWIS Tester fuel pressure display Setpoint value for all-wheel drive vehicles Absolute fuel pressure 6.2 bar +/- 0.2 bar - Switch off ignition, switch off the PIWIS Tester and disconnect adapter line in the vehicle.