Turbocharger: Testing and Inspection

TURBOCHARGER, CHECKING

Special tools, testers and auxiliary items
- VAG 1397 A Turbocharger tester

Checking conditions
- No malfunctions stored in Diagnostic Trouble Code (DTC) memory
- Perform Output Diagnostic Test Mode
- No leaks from intake and exhaust systems
- Wastegate control line is not blocked, loose or leaking
- No engine or fuel injection mechanical malfunctions, e.g. start of injection, fuel injectors and compression pressure
- Engine oil temperature 89 °C minimum

Checking
- Measure boost pressure under full load, while driving on the road
- Test duration per measurement: 10 seconds maximum





- Disconnect -1- Wastegate Bypass Regulator valve -N75- from connector -2-





- Disconnect connecting hose running between intake manifold and Diesel Engine Control Module -J248-
- Using a tee, connect VAG 1397 A Turbocharger tester
- Selecting measuring range

NOTES:
- To operate the VAG 1397A Turbocharger tester see manufacturers operating instructions
- Ensure that all of the hoses are connected so there is no possibility of leakage
- If boost pressure is being measured while driving, a second person must be used to read and operate the turbocharger tester
- Ensure that the pressure hose is not trapped between the hood and the body

- Measure boost pressure at Wide Open Throttle:

On an open road:
- In 3rd gear (manual) or with Transmission Range selector lever in position 2 (automatic)
- With engine speed at 3500 to 4000 rpm

Or while driving:
- In 2nd gear (manual) or with Transmission Range selector lever in position 1 (automatic)
- Under Wide Open Throttle acceleration while watching the tachometer

NOTE: Do not apply the brakes while taking boost measurements (unless of course it becomes necessary). The Engine Control Module responds to braking by reducing the fuel quantity; which can lead to incorrect boost measurements.

- Press "M" button (memory) on VAG 1397A Turbocharger tester when the engine speed falls between 3500 and 4000 rpm, then read out the boost values
- Specification: 0.50 to 0.65 bar (relative pressure)

If specified boost pressure not obtained
- Check Wastegate Bypass Regulator valve and replace if necessary
- Repeat boost pressure check

If specified boost pressure still not obtained
- Replace turbocharger

If boost pressure is exceeded
- Check Wastegate Bypass Regulator valve -N75- (flow between turbocharger and valve to wastegate should not be blocked when connector is disconnected)
- Ensure that the wastegate valve is securely mounted on the turbocharger
- Check wastegate and operating rod, replace if necessary
- Check Wastegate Bypass Regulator valve shaft mounting in turbocharger for ease of movement. If corroded together; replace turbocharger