With Manufacturer's Scan Tool

Charge air pressure system, checking





Special tools and equipment
^ VAG 1390 Vacuum pump
^ Fluke 83 Multimeter
^ VW 1594 Adaptor kit
^ VAG 1598/22 Test box
^ VAG 1551/1552 with VAG 1551/3 adaptor cable
^ Wiring diagram

Checking conditions
^ No DTC,s stored in Diagnostic Trouble Code memory
, Refer to Powertrain Management
^ No leaks from intake and exhaust systems.
^ No stored DTC,s from engine and fuel injection system, e.g. start of injection, fuel injectors and compression pressure.
^ Engine oil temperature 80°C minimum.

Test sequence
Observe following if test and measuring instruments are required during a test drive:
^ Test and measuring instruments must be secured to the rear seat and operated by a 2nd person from this location.

CAUTION: If test and measuring instruments are operated from the front passenger seat and the vehicle is involved in an accident, there is a possibility that the person sitting in this seat could receive serious injuries when the airbag is triggered.

- Connect VAG 1551/1552 Scan Tool

- Start engine and let idle
- Press 0 and 1 buttons to select Address word 01 "Engine electronics"





Display will appear as shown

- Press 0 and 8 buttons to select Function 08: "Read measuring value block"
- Press Q button to enter input





Display will appear as shown

- Press 0, 1 and 1 buttons to select Display Group 11
- Press Q button to enter input
Read measuring value block 11 --> 840 rpm 938 mbar 978 mbar 92 %

Display will appear as shown
- Accelerate vehicle in 3rd gear from about 1500 rpm under Wide Open Throttle.
- Press VAG 1551 PRINT button at approximately 3000 rpm.
Read measuring value block 11 --> 3090 rpm 1866 mbar 1917 mbar 62 %
Specification: 1700 to 2200 mbar (in display zone 3)
If specification not obtained:
- Perform Output Diagnostic Test Mode to activate Wastegate Bypass Regulator valve:

Display will appear as shown

Note: The valve must function and the charge air pressure control rod must move back and forth (at least 3 to 4 times), as long as there is a vacuum in the vacuum reservoir.

If rod moves but pressure specifications are not obtained
- Replace turbocharger.
If rod does not move because solenoid valve is not working:
- Check Wastegate Bypass Regulator valve -N75-
- Check vacuum hoses
If rod does not move but solenoid operates:





- Connect VAG 1390 vacuum pump to Wastegate Bypass Regulator valve and check rod for ease of movement.
If rod does not move easily:
- Replace turbocharger assembly.