Fuel Delivery and Air Induction: Service and Repair

WM 2430B1 Filling and bleeding the DFI fuel high-pressure system (includes bleeding fuel distribution pipe)

Preliminary work

1. Repairs in the high-pressure area resulting in air getting into the high-pressure system (e.g. replacing the high-pressure pump, removing and installing fuel distribution pipes).
2. Perform a leak test using helium (high-pressure system is dry or contains considerable amounts of residual gases).
3. Low-pressure area and the fuel supply system are in perfect condition.
- Fuel level is sufficient.
- Fuel feed system is working perfectly.

Filling and bleeding the DFI fuel high-pressure system

Filling and bleeding the fuel high-pressure system

1. Start the engine and let it run at idle speed for about 5 minutes. This can result in a rough-running engine and the Check Engine warning light in the instrument cluster can be activated.
- If this happens, continue with Step 2.
- If this does not happen, continue with Step 7.

2. Turn off the engine after letting it run for 5 minutes and switch off the ignition.
3. Switch on ignition.
4. Read out the fault memory of the DME control unit using the PIWIS Tester and erase fault code P1026 - "Fuel high-pressure implausible".
5. Switch off ignition.
6. Switch the ignition on and start the engine.

If the engine is still rough-running, let the engine run again for around 5 minutes at idle speed. Then repeat Steps 2 to 6 as often as required until you get to Step 7.
7. The bleeding process is complete when the engine runs smoothly, the Check Engine warning light is no longer activated and fault code P1026 is no longer entered in the fault memory.
8. Perform a test drive.