Turbocharger and Charge Pressure Regulating Valve, checking
Turbocharger and Charge Pressure Regulating Valve, checking
Special tools and equipment
^ Turbocharger tester V.A.G 1397 A
^ VAS 5051 with VAS 5051/1
or
^ V.A.G 1551 with V.A.G 1551/3 A
Test requirements:
^ Vehicle diagnostic, testing and information system VAS 5051 or fault reader V.A.G 1551 Scan Tool connected.
^ All hoses and pipes must be checked for correct seating and leaks.
^ Diagnostic Trouble Code (DTC) memory has been checked:
^ Output Diagnostic Test Mode (DTM) has been performed:
Test sequence
WARNING!
^ Always attach testers and measuring instruments to the back seat and have a second person operate them from there.
^ If test equipment were operated from the front passenger seat, the person sitting there could be injured if the front passenger airbag were triggered in the event of an accident.
^ Connect T piece and measuring hose of turbocharger tester VAG 1397 A to intake manifold (front).
^ Route measuring hose under rear edge of hood and into passenger compartment via right hand window.
^ Switch on turbocharger tester and set measuring range selector switch to position -I- (absolute pressure).
^ Connect measuring hose to connection -1-.
Note:
^ Hose connections must be completely airtight, otherwise measurements will not be correct.
^ Ensure that measuring hose is not pinched at hood or side window.
^ Pressing memory key M on turbocharger tester will store the last measured value until memory key M is pressed again or tester is switched off
^ The decimal point in the display flashes to indicate that the value is being stored.
^ If the battery voltage of the turbocharger tester drops below the minimum level, an arrow will appear at the top left of the display.
^ Before checking, drive vehicle quickly for at least 3 km (choose a safe route that does not include stopping).
^ A second mechanic is required to note readings with the vehicle moving.
^ Read measured value block Display group 115, engine idling.
^ Accelerate vehicle from 2000 rpm at wide open throttle in third gear, and observe rev counter.
^ At approximately 2500 rpm press print key on VAS 5051 or PRINT key on V.A.G 1551 and at same time press recall button -M- on V.A.G 1397 A.
Note: The charge pressure level is measured with turbocharger tester V.A.G 139 71A. The vehicle diagnostic, measuring and information system VAS 5051 or the V.A. G 1551 Scan Too/ is used to check whether the charge pressure is being registered by the control module.
- Specified value on V.A.G 1397 A: 1.700 to 1.800 bar
- Specified value on V.A.G 1551 or on VAS 5051 in display zone 4: 1700 to 1800 bar
If specified value not attained Refer to, table
Charge pressure control malfunctions (Part 1 Of 2):
Charge pressure control malfunctions (Part 2 Of 2):
Charge pressure control malfunctions
1) If the charge pressure is too high the fuel supply will be interrupted in order to protect the engine. This results in misfiring at high engine speeds.
Effects of leaks in intake or exhaust system
Leak downstream of mass air flow sensor
^ Effect: Loss of power
Possible fault sources:
1 - Connection hoses between mass air flow sensor and exhaust turbocharger
2 - Connection hose for crankcase vent
3 - Connection hose to mechanical air recirculation valve
Leak downstream of exhaust turbocharger
^ Effect: Charge pressure too low
Possible fault sources:
1 - Connection hoses and pipe between exhaust turbocharger and charge air cooler
2 - Hose between charge air cooler and intake pipe
3 - Charge air cooler
4 - Seal of Charge Air Pressure sensor -G31- (in charge air cooler)
5 - Sealing between throttle valve control module and intake pipe
6 - Sealing between intake pipe and cylinder head
Effects of leaks on exhaust side
^ Effect: Charge pressure too low, possible exhaust smell, soot traces in engine compartment
Possible fault sources:
1 - Exhaust turbocharger exhaust manifold connection
2 - Exhaust manifold/cylinder head connection