Test requirements:
- Read DTC memory. See DIAGNOSTIC MODE 3: CHECK DTC MEMORY .
- Output Diagnostic Test Mode (DTM) performed
- Minimum engine oil temperature: 60 °C.
- All vacuum connections are leak tight
- Remove engine cover -B-, remove bolts (arrows) to do so.
- Using T-piece connect VAG1397A Turbocharger Tester test hose to fuel pressure regulator (arrow).
- Guide test hose over rear corner of hood and through right window into vehicle interior.
- Turn turbocharger tester on and select measuring range -I- (absolute pressure).
- Connect test hose to connection flange -I-.
NOTE:
- Hoses must be connected so there is no possibility of leaks, otherwise incorrect readings may result.
- Ensure test hose is not pinched at hood and body.
- By pressing memory button "M" on turbocharger tester, the last test value is saved until either memory button "M" is pressed again or the turbocharger tester is shut-off.
- A blinking comma in display field indicates a value has been saved.
- An arrow appears in the top left corner of display field if turbocharger tester battery voltage drops below the permissible specification.
- Before testing drive vehicle rapidly at least 3 km (without frequent stops and similar).
- A second technician is required because the indicated values must be read out in the vehicle interior.
- Observe safety precautions. See TURBOCHARGER AND BOOST PRESSURE REGULATOR VALVE, CHECKING .
- Accelerate vehicle in 4th gear at full throttle from 2000 RPM and watch tachometer.
- At 3000 RPM press memory button "M" on turbocharger tester.
- Specified value: 1.390 ... 1.490 bar
NOTE:
If there is no available boost pressure and a rumbling sound can be heard from the engine compartment, these are caused by the following:
- Boost pressure recirculation valve malfunctioning.
- Vacuum line to recirculation valve leaking or slipped off.