Audi Workshop Service and Repair Manuals

Renewing vacuum unit with position sender for charge pressure positioner -G581- Special tools and workshop equipment required

t  Socket -T10422-

t  Ring spanner -T10423- t  Vehicle diagnostic tester   Caution The tools listed, in particular the socket -T10422-, are only intended for use according to the procedure described in the following; do NOT use the tools for other bolted connections. There is danger of deformation if the specified torques are exceeded.   Note A replacement part set is available → Electronic parts catalogue for renewing the vacuum unit with position sender for charge pressure positioner -G581-.

Removing –  Remove air cleaner housing with air mass meter and connecting pipe → Rep. gr.23.

–  Press release tabs and disconnect crankcase breather connecting pipe -1- from cylinder head cover. –  Move clear vacuum hoses -arrows-. –  Unscrew captive bolt -2-, swivel air pipe with connection to rear and detach from turbocharger. –  Seal opening on turbocharger with sealing cap from replacement part set.

–  Detach heat shield sleeve around electrical connector -1-. –  Unplug electrical connector -1- at position sender for charge pressure positioner -G581-. –  Detach vacuum hose -2- from vacuum unit of turbocharger.

–  Depending on version, remove nut -arrow- securing oil supply line/vacuum line to cylinder head.

Make an improvised tool (14 mm) to counterhold connection for oil supply line, as shown. t  A = 110 mm t  B = 25 mm   Caution It is important that you counterhold connection when loosening oil supply line. Risk of further damage occurring later.

–  Counterhold connection using improvised tool and remove oil supply line -arrow- from turbocharger. –  Seal opening for oil supply line in turbocharger with plug from replacement part kit.

–  Counterhold lock nut -B- with ring spanner -T10423- and remove securing nut -A- from control rod using socket -T10422-.

–  Unscrew bolts -arrows- securing vacuum unit and detach vacuum unit -A-. Installing   Caution Only use new bolts and nuts from replacement part kit. –  If necessary, remove bottom nut securing control rod from new vacuum unit. –  Screw lock nut on control rod by hand as far as stop towards vacuum unit. –  Guide control rod through adjusting lever on turbocharger, fit vacuum unit -A- and secure bolts.

–  Tighten securing bolts -arrows- to 8 Nm.   Note Please ensure that guide can be moved easily on control rod.

–  Remove protective cap, fit oil supply line -arrow- on turbocharger and tighten to 22 Nm.

–  Plug in connector -2- at position sender for charge pressure positioner -G581- and fasten heat shield sleeve. –  Connect vehicle diagnostic tester. Selecting operating mode: –  On touch screen, press button for „Vehicle self-diagnosis“. Selecting vehicle system: –  On touch screen, press button for „01 - Engine electronics“. The display will show the identification and coding of the engine control unit. Selecting diagnostic function: –  On touch screen, press button for „011 - Measured values“. –  On the numeric keypad, enter measured value block „120“ and confirm your entry with „Q“ key. –  Connect hand vacuum pump -VAS 6213- to vacuum unit. –  Create voltage of 0.760 V by generating a vacuum (observe minimum value of measured value block).   Caution During the following adjustment procedure for the control rod, the vacuum and the voltage of 0.760 V must be maintained.

–  Slowly screw lock nut -B- for control rod downwards by hand. Adjusting lever is on bottom stop. –  Counterhold lock nut -B- and screw securing nut -A- on control rod against adjusting lever. Tighten slightly using ring spanner -T10423-. –  Release vacuum pressure from vacuum unit. –  Observe minimum value of measured value block: value of 3.30 ... 3.90 V should be displayed (unpressurised). –  Apply socket -T10422-, counterhold lock nut -B- using ring spanner -T10423- and tighten securing nut -A-.   Caution Create vacuum of 0.75 ± 0.05 bar for vacuum unit to ensure that adjusting lever is positioned at stop. A voltage of 0.760 V should build up.

Voltage value OK –  Press locking plate onto control rod by hand and turn by 90° in direction of -arrow-. –  Seal connection between control rod and securing nut with sealing paint from replacement part kit.

Voltage value not OK –  Counterhold lock nut -B-, loosen securing nut -A- on control rod and adjust value by turning lock nut -B-. –  Counterhold lock nut -B-, screw securing nut -A- in other direction and tighten connection using socket -T10422-.

–  Press locking plate onto control rod by hand and turn by 90° in direction of -arrow-. –  Seal connection between control rod and securing nut with sealing paint from replacement part kit.

Continued –  Depending on version, fit nut -arrow- securing oil supply line/vacuum line to cylinder head and tighten connection. –  Remove sealing cap from turbocharger. –  Fully assemble engine components. –  Start engine and erase event memory → Vehicle diagnostic tester. –  Check adjustment as follows: Selecting diagnostic function: –  On touch screen, press button for „006 - Basic setting“. –  On the numeric keypad, enter measured value block „120“ and confirm your entry with „Q“ key. –  On bottom half of touch screen, press button for „Activate“. –  Observe value on bottom part of display: value should fluctuate between 0.65 ... 0.85 V and 3.30 ... 3.90 V (vacuum unit is moved to both limit stops alternately). Voltage values OK: –  Exit basic setting.