2. Checking Control of Fuel Pressure

Checking Control Of Fuel Pressure







CAUTION: The pressure in the fuel system can reach approximately 650 kPa when this diagnostic trouble code (DTC) is stored. Use an adapted manometer.

HINT: The following method is for checking the fuel system's pressure by reading out fuel pressure and the fuel pump's working load. If pressure gauge for pressure up to 650 kPa is connected, the fuel pressure sensor can also be checked during the test.

- Disconnect the pressure gauge if it is not adapted for higher pressures than 650 kPa.
- Run the engine until it is warm and let it idle.
- A/C off.
- Read off fuel pressure and the fuel pump's working load.
- The upper digital display and the graphic display (red characters) show absolute fuel pressure, calculated from the fuel pressure sensor.
- The middle digital display (blue characters) shows the fuel pump's current working load to hold current fuel pressure. (Normal value 50% ±10%.)
- The lower digital display shows the relative fuel pressure (white characters), calculated from the fuel pressure sensor and the atmospheric pressure sensor (=absolute pressure minus atmospheric pressure). If a pressure gauge is connected during the test it shall show this pressure.

Check the value for fuel pressure together with the value for the fuel pump's working load. Requested pressure is 380 kPa at idle. Fuel pressure (relative) lower than 380 kPa together with high working load on the fuel pump indicates a malfunction of the pressure control.

Is the function OK?

YES: Refer to 3. Checking Components. 3. Checking Components
NO: Refer to 4. Checking Components. 4. Checking Components