Fuel Pressure, Checking While Driving

Fuel Pump, Checking

Special tools, testers and auxiliary items required

• Pressure Tester (VAS 6550)

• Remote Control (V.A.G 1348/3A)

• Test Instrument Adapter/DSO (5-pin) (VAS 5565)

• Multi-meter (V.A.G 1715)

• Wrench (T10202)

• Torque Wrench (40-200 Nm) (V.A.G 1332)

• Measuring Container, 2 Liter

Fuel Pressure, Checking while Driving

• If there are concerns about the driving behavior, the cause may be low fuel pressure. Malfunctions in the high pressure area can also be caused by low fuel pressure. This test checks the high and low fuel pressure while driving. The high fuel pressure is read from the Engine Control Module (ECM). The pressure tester (VAS 6550) measures the low fuel pressure and transmits the reading to the vehicle diagnosis and service system (VAS 5052 B).

• This test can be a component of "Guided Fault Finding" if there is a Diagnostic Trouble Code (DTC) entry. It can also be started in the vehicle diagnosis and service system (VAS 5052 B) under "Function and Component Selection".

Special tools, testers and auxiliary items required

• Pressure gauge (VAS 6550)

• Hose adapter (6550/2)

• Vehicle diagnosis and service system (VAS 5052 B)

• Cable Set (VAS 5051/66)


The fuel supply line is under pressure! Wear eye protection and protective clothing in order to avoid injuries by contact with fuel. Before disconnecting the connection, wrap a cloth around the connection. Then, disconnect the hose connection carefully to release the pressure.

- Remove the fuel supply line (metal coupling) - arrow - and absorb the leaking fuel with a cleaning cloth.





• Press in the securing ring to disengage the fuel line.

- Connect the (VAS 6550) to the fuel supply line using (VAS 6550/2).





- Lay a cleaning cloth on the engine cover. Lay the (VAS 6550) on the clean cloth and secure with cable ties - arrows -.


Secure the (VAS 6550) carefully so that it does not slide back and forth during the road test. Make sure there is enough clearance to all moving or hot components.

- Secure the drain valve with a cable tie - arrow - so that it does not open.





- Connect the (VAS 5051/66) to (VAS 6550) and route it through the vehicle interior.


Route the (VAS 5051/66) carefully. Make sure there is enough clearance to all moving or hot components.

- Connect the (VAS 5051/66) to (VAS 5052 B) and turn the (VAS 6550) on.

If the fuel pressure test is done within "Guided Fault Finding", follow the instructions from the vehicle tester.

If the fuel pressure test is done without "Guided Fault Finding", proceed as follows:

- Connect the (VAS 5052 B) to the vehicle.

- Select "Guided Fault Finding" in (VAS 5052 B).

- Perform the vehicle identification.

- Select the following menu items one after another using the Go to button:

• Function/Component Selection

• Powertrain

• Engine

• 24-Fuel Preparation/Injection

• Mechanical Components

• High Pressure Pump

- Follow the instructions from the (VAS 5052 B).


Always secure testing and measuring equipment on the rear seat during a road test.

This equipment should only be operated by a passenger when driving.