Fuel Pressure, Checking: Notes
Special Tools And Workshop Equipment Required
- Diesel Pressure Tester Kit:VAS6551
- Diesel Pressure Tester Kit - Adapter Set: VAS6551/5
- Hose Clip Pliers:VAG1921
- Trim Removal Wedge:3409
- Vehicle Diagnostic Tester
Remember, the fuel pump will turn on when a door is opened, if the battery is connected. Fuel may leak out when the system is open.
Test Conditions
- Connect the battery charger. The voltage must be minimum 12.5 V. Refer to BATTERY, DISCONNECTING AND CONNECTING .
- Fuses OK. Refer to Wiring Diagram .
- Fuel Pump Control Module -J538- is OK. Refer to Vehicle Diagnostic Tester.
- The fuel filter is OK.
- Make sure the vehicle is level.
- Fuel tank minimum 1 /2 full.
- All electrical consumers such as, for example, headlamps and rear window defogger, must be off.
The vehicle must be fueled with diesel fuel treated for the season. Under some conditions, summer diesel fuel can coagulate at low winter temperatures.
Diesel fuel bought in the summer can be filtered to 0 °C (32 °F).
Diesel fuel sold during the transition time can be filtered to -10 °C (14 °F).
Diesel fuel bought in the winter can be filtered to -20 °C (-4 °F).
Test a sample in the winter if there is doubt.
The sample should set outside at low outside air temperature for approximately 1 hour.
If the fuel coagulates at temperatures down to -20 °C (-4 °F), then this diesel fuel is not suited for low temperatures. This coagulation can plug the screen in the fuel delivery unit as well as in the fuel filter.