SEAT Workshop Service and Repair Manuals

Turbocharger and charge pressure regulating valve: check Special tools and workshop equipment required

t  Turbocharger tester -VAG 1397A-

t  Central diagnosis -VAS 505X- Test prerequisites l  All hoses and pipes checked for tight fit and leaks l  Fault memory interrogated, final control diagnosis performed → Vehicle diagnostic, testing and information system VAS 5051. Checking sequence   WARNING t  The testing and measurement equipment must always be fitted to the rear seat and from there be operated by a second person. t  If test equipment is operated from the front passenger's seat, the occupant could suffer injury in the event of an accident if the front passenger's airbag is triggered.

–  Connect T-piece with test hose of turbocharger tester -V.A.G 1397 A- to intake manifold (front). –  Route test hose under rear edge of bonnet and through right window into passenger compartment.

–  Switch on turbocharger tester and set measuring range switch to -I- (absolute pressure). –  Connect the measurement tube to the connection sleeve -I-.   Note t  When connecting the lines, ensure for complete tightness. Otherwise, measuring faults may occur. t  Take care not to trap measurement hose at bonnet and side window. t  Pressing memory button „M“ on turbocharger tester causes last measured value to be stored until memory button „M“ is pressed again or tester is switched off. t  Storage is indicated by flashing of decimal point in display zone. t  An arrow appears in the top left corner of the display if battery voltage of turbocharger tester drops below permitted specification. t  Before checking the vehicle, drive min. 3 km (avoiding traffic lights or the like). t  Second person is required to read out values displayed whilst driving.

–  With the ignition switched off, connect the Vehicle Diagnosis, Testing and Information System -VAS 505X- to the diagnostic terminal. –  Start engine. Indicated on the vehicle diagnostic, testing and information system -VAS 505X-: –  Briefly press the key „Vehicle self diagnosis“.

Indicated on the vehicle diagnostic, testing and information system -VAS 505X-: –  Select vehicle system „01 - Engine electronics“ in menu -1-. –  Wait until next display appears.

Indicated on the vehicle diagnostic, testing and information system -VAS 505X-: –  From list -1-, select diagnostic function „08 - Read measured value block“.

Indicated on the vehicle diagnostic, testing and information system -VAS 505X-: 1 -  Enter the value group, input value max. = 255 –  Use keypad -2- to enter „Display group number 115“ and confirm by touching the Q key. –  Take vehicle for a test drive. –  Accelerate vehicle in 3rd gear from 2000 rpm at full throttle and observe rev counter. –  Press the button in -VAS 505X- when reaching approx. 2,500 rpm and simultaneously press the memory button -M- on -V.A.G 1397 A-.   Note The charge pressure value should be determined using the turbocharger tester -V.A.G 1397 A-. The Vehicle diagnostic, testing and information system -VAS 505X- is used to check whether the charge pressure is also being registered in the control unit.

Indication on -V.A.G 1397 A-: l  Specification: 1.500 ... 1.600 bar.

Indicated on the vehicle diagnostic, testing and information system -VAS 505X-: –  Check the display in display field -4-. l  Specification: 1.500 ... 1.600 Millibar. If specification is not obtained:

Fault	Possible causes of the fault
Charge pressure below specification	t  Solenoid valve for charge pressure control -N75- defective. Check in the „guided fault finding“ → Vehicle diagnostic, testing and information system VAS 5051 t  Hose connections to solenoid valve for charge pressure control -N75- defective, check → Chapter t  Charge pressure regulating valve in turbocharger stuck open t  Leak between turbocharger and intake manifold. Effects → Chapter t  Mechanical air recirculation valve defective. Check → Chapter t  Recirculation valve for the turbocharger -N249- defective. Check in the „guided fault finding“ → Vehicle diagnostic, testing and information system VAS 5051 t  Turbocharger defective; renew → Chapter
Charge pressure above specification → Remark	t  Vacuum unit for charge pressure regulating valve defective. Renew turbocharger → Chapter t  Air leaks in hoses or connections to vacuum unit for charge pressure control (via solenoid valve for charge pressure control -N75-). Check → Chapter t  Charge pressure regulating valve in turbocharger sticking in closed position. Renew turbocharger → Chapter

1)	If the charge pressure is too high the fuel supply will be interrupted in order to protect the engine. Misfiring will then occur at high engine speeds.