Fuel Pressure Sensor, Checking

Fuel Pressure Sensor, Checking

Special tools, testers and auxiliary items required
- Assembly tool T10118
- Socket wrench insert 27 mm VAS 5301/7
- Pressure sensor tester VAS 6394
- Test adapter VAS 5570

Work Procedure

CAUTION: The fuel pressure sensor is pressurized. Wear protective goggles and protective clothing to prevent injuries and contact with skin. Wrap a cloth around the connection point before loosening the fuel pressure sensor. Then release pressure by carefully loosening.

- Remove the fuel pressure sensor G247.







- Remove the locking bolt - 2 - and install the fuel pressure sensor G247 in the pressure sensor tester VAS 6394/1.Tightening specification: 22 Nm.







- Coat the adapter VAS 6294/2 sealing point with clean engine oil and install it in the fuel rail. Tightening specification: 22 Nm.







- Connect the pressure sensor tester VAS 6394/1 pressure line to the adapter VAS 6394/2.
- Connect the fuel pressure sensor - 1 - and electrical connector on the sensor using the pressure sensor tester VAS 5570.
- Install the engine cover/air filter and connect the mass air flow sensor G70.







- Switch the pressure sensor tester VAS 6394/1 on by pressing the button - A - briefly.

NOTE:
- Holding the button - A - for 2 seconds switches on the illumination for 20 seconds.
- If the pressure sensor tester VAS 6394/1 does not display 0 bar, set it back to zero See operating instructions.

- Connect the tester to the diagnostic connector.
- Switch on ignition.
- Press the following buttons in the tester screen one after another.

Vehicle Self-Diagnosis
On Board Diagnosis (OBD) micro
01 - Engine Electronics micro
011 - Measure Values micro
- Select the measured value block 1 4 0 and confirm with the Q button.

Display field 3 shows the fuel pressure actual value as measured by the fuel pressure sensor G247.
- Start engine.
- Compare the pressure displayed by the pressure sensor tester VAS 6394/1 with the actual value displayed on the vehicle tester.
- The pressures may have a maximum difference of 5 bar.
- If the difference is greater than 5 bar, replace the fuel pressure sensor G247.

CAUTION: The pressure sensor tester VAS 6394 is under high fuel pressure. Disconnect the connector from the fuel pressure sensor G247 when the engine is running. This reduces the pressure to approximately 6 bar. Switch off ignition. Place a cloth around the fuel pressure sensor G247, then carefully loosen the to release the remaining pressure.

- Repeat the test with the new fuel pressure sensor G247 and compare both measured values.

If the Measured Value Do Not Match Again
- Perform a wiring test.