Fuel Pressure Regulator and Holding Pressure, Checking

Fuel Pressure Regulator And Holding Pressure, Checking (Engine codes AVH)

The fuel pressure regulator regulates the fuel pressure depending on intake manifold pressure.

Special tools and equipment







- V.A.G 1318 Pressure gauge
- 1318/10 Adapter
- 1318/11 Adapter
- 1318/16 Hose adapter
- V.A.G 1921 Spring-type clip pliers


Work sequence







- Remove fuse No. 28 (fuel pump) from fuse holder.

WARNING: The fuel system is under pressure. Before opening the system place a cloth around the connection. Then release the pressure by carefully loosening the connection.







- Remove supply line -1- and collect leaking fuel with a cloth







- Connect pressure tester V.A.G 1318 with adapters V.A.G 1318/10, V.A.G 1318/11 and V.A.G 1318/6.
- Open pressure tester shut-off valve. Handle points in through-flow direction (arrow).
- Install fuse 28 (fuel pump) in fuse holder
- Start engine and run at idling speed.
- Measure fuel pressure.

Specification: approx. 2.5 bar







- Disconnect vacuum line -1- from union -2-. Fuel pressure must increase to approx. 3.0 bar.

If specification is not obtained.
- Check quantity supplied by fuel pump. [1][2]Fuel Pump, Checking - II

If specification is obtained.
- Switch ignition off.
- Hold pressure and check for leaks. Observe pressure drop on gauge. After 10 minutes, there must be a residual pressure of at least 2.0 bar.

If holding pressure drops below 2 bar.
- Start engine and run at idling speed.







- Switch ignition off after pressure has build-up. At same time close pressure tester V.A.G 1318 shut-off tap (handle at right angles to through-flow direction -arrow-).
- Observe pressure drop on gauge.

If pressure does not drop
- Check fuel pump non-return valve [1][2]Fuel Pump, Checking - II

If pressure drops again.







- Open shut-off tap on pressure tester V.A.G 1318 (handle point in direction of flow -arrow-).
- Start engine and run at idling speed.







- Switch ignition off once pressure has built-up and clamp off return hose at same time.

If pressure does not drop:
- Replace fuel pressure regulator
- Erase DTC memory to return learned values to a neutral (default) position, Interrogating and erasing DTC memory

If pressure drops again.
- Check line connections, O-rings on fuel rail and injectors for leaks.
- Check pressure tester for leaks.

If a leak on vehicle has been corrected.
- Erase DTC memory to return learned values to a neutral (default) position, Interrogating and erasing DTC memory With Manufacturer's Scan Tool

NOTE: Before removing the pressure tester, remove fuse 28 again and place a cloth around the connection to be loosened.