Boost Pressure Control

Special testers required:
- VAG 1397 A Turbocharger tester

Checking requirements:
- Intake and exhaust systems leak tight
- Engine oil temperature 80 °C minimum

NOTES:
- Boost pressure is measured under full load while driving on the road or on a dynamometer.
- 10 seconds maximum duration per measurement





Checking procedure:
- Disconnect hose between intake manifold and recirculation valve at intake manifold and using T-piece, connect VAG 1397 A turbo charger tester.
- Select measuring range 1.

NOTES:
- To operate turbocharger tester see operating instructions.
- Hoses must be connected so there is no possibility of leaks.
- Ensure pressure hose is not trapped between hood and body.

CAUTION! Always use a second technician to take measurements via the VAG 1397A Turbo charger tester when driving on the road.

Measure boost pressure at Wide Open Throttle:
On a dynamometer:
In 3rd gear or Transmission Range selection 2 between 3000 and 4000 rpm
On the road test drive:
In 2nd gear or Transmission Range selection 1, accelerate vehicle at Wide Open Throttle and hold vehicle between 3000 and 4000 rpm by braking at the same time

- Press memory button "M" on turbo tester and read display.
Relative pressure specification: 1.350 to 1.650 bar

If specification exceeded:
- Test Wastegate Bypass Regulator valve N75
- Check to ensure that flow in hose from turbo to pressure unit (via valve) is not blocked when connector is pulled off.
- Ensure control valve pressure unit is securely mounted on turbo.
- Check charge pressure control valve shaft mounting in turbo ease of movement.

If corroded together:
- Replace turbocharger assembly

If boost pressure not attained:
- Check Wastegate Bypass Regulator valve N75.