Checking Fuel Pressure

WARNING: This page is about a different car, the 2024 Porsche Macan, 2023 Porsche Macan, 2022 Porsche Macan, 2021 Porsche Macan, and 2020 Porsche Macan. However, it is still accessible from the selected car via links, so may be relevant.

WARNING: Toxic substances

Danger of poisoning or suffocation
Danger of burns to the eyes and skin
1. → Ventilate the work area well.
2. → Never ingest or inhale.
3. → Read specific information on the Hazard Sheet.
4. → Wear personal protective gear.
5. → Do not smoke, eat or dink in the work area.

WARNING: Highly inflammable or explosive materials

Danger of fire or explosion
1. → Avoid contact with hot parts or sources of ignition.
2. → Use suction to remove ignitable vapours.
3. → Attach warning sign in a clearly visible position.
4. → 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.
5. → Secure collection containers/vessels to prevent them from tipping over.

Information

The battery voltage must not fall below 12.5 volts during the fuel pressure check.

Information

Faults in the fuel high-pressure injection system can also be caused by defects in the pre-delivery system (fuel low pressure).
In the event of problems in the fuel high-pressure injection system, the pre-delivery system should be checked first.

Information

The fuel holding pressure must only drop to max. half the stop pressure in one hour.

Disconnect supply line.

1.1 Release quick connector -3- on engine compartment section -2- and disconnect it from underbody section -1- .

1.2 Soak up escaping fuel using suitable aids and close off line connection for engine compartment section -2- using a suitable stopper.

Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Underbody section to engine compartment section

Connect test tools -1 to 3- .

Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Test tools for checking fuel pressure
1. 2.1 Connect pressure gauge -1- from tool set > V.A.G 1318 - K-Jetronic pressure tester on vehicle side using > V.A.G 1318 - K-Jetronic pressure tester adapter/17 - and/23 -2 - and 3- to supply line.
2. 2.2 Make sure that the shut-off valve on the pressure gauge is closed.
Perform fuel pressure test using the PIWIS Tester.
1. 3.1 Switch on the PIWIS Tester and connect it to the vehicle.
2. 3.2 Switch on the ignition.
3. 3.3 Select the Diagnostics function.
4. 3.4 Select the DME control unit in the control unit overview and confirm by pressing F12.
5. 3.5 Switch to the Drive links/checks menu item.
6. 3.6 Select the Drain fuel tank function and press F12 to confirm your selection.
7. 3.7 Activate the Drain fuel tank function (= activate fuel pump) by pressing F12.
8. 3.8 Read off the pressure on the pressure gauge and compare it with the required value:
  - Pressure 6.5 bar +/- 0.25 bar
9. 3.9 End the Drain fuel tank function by pressing F8 = Stop.
10. 3.10 Switch off ignition and remove the PIWIS Tester.
11. 3.11 Check fuel holding pressure.
  1. 3.11.1 Continue to apply pressure to the fuel system for one hour.
  2. 3.11.2 Read off the pressure shown on the pressure gauge again.
  Maximum permissible pressure drop: > Pressure 1 bar