Fuel Pressure Sensor/Switch: Testing and Inspection

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 6394/1
- Adapter VAS 6394/2
- Test Adapter VAS 5570
- Torque Wrench V.A.G 1331
- Vehicle Diagnostic, Testing, and Information System Vas 5051B

Work Procedure
- Remove engine cover.
- Remove the fuel pressure sensor.







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







- Remove locking bolt - 2 - and install the fuel pressure sensor in the pressure sensor tester VAS 6394/1. Tighten to 22 Nm.
- Connect pressure sensor tester VAS 6394/1 pressure line to adapter VAS 6394/2.







- Connect fuel pressure sensor and electrical connector with the test instrument adapter VAS 5570







- Switch 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 operating instructions

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

Vehicle Self-Diagnosis

On Board Diagnostic (OBD) micro

01 - Engine Electronics micro

011 - Test Instruments micro

- Select 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.

- Start engine.
- Compare 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.

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

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

If the measured value does not match again, perform a wiring test.