Compression, Checking

Special tools and workshop equipment required 

• Spark Plug Removal Tool3122 B
• Compression TesterV.A.G 1763
• Ignition Coil PullerT40039

Procedure

• Engine oil temperature min. 30 °C (86 °F)
• Battery voltage min. 12.5 V

-- Turn off ignition.

-- Disconnect electrical connector on Engine Speed (RPM) sensor -G28- -arrow- at right of transmission.

Fig 1: Locating Engine Speed (RPM) Sensor -G28- Electrical Connector

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-- Disconnect electrical connector -2- at Mass Airflow (MAF) sensor 2 -G246-.

Fig 2: Locating Electrical Connector, Air Guide Hose, And Retaining Clips

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-- Remove left air guide hose -1- from air duct.

-- Release retaining clips -3- and remove upper left section of air filter housing.

-- Disconnect hose -1- to Secondary Air Injection (AIR) pump.

Fig 3: Identifying Hose To Secondary Air Injection Pump, Electrical Harness Connector, Right Air Guide Hose, And Retaining Clips

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-- Disconnect electrical harness connector -4- at (MAF sensor -G70-.

-- Remove right air guide hose -3- from air duct.

-- Release retaining clips -2- and remove upper right section of air filter housing from lower part.

Vehicles with air suspension:

-- Press circlip -1- forward from hose coupling.

Fig 4: Circlip, Release Ring And Ventilation Hose

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-- Press release ring -2- down -arrows- and remove vent hose -3- from upper section of air filter.

All Vehicles

-- Remove oil dipstick -1- from guide tube.

Fig 5: Identifying Oil Dipstick, Bolts & Ignition Coils Electrical Harness Connectors

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-- Remove the bolts -2 and 3-.

-- Disconnect electrical harness connectors at ignition coils.

-- Press electrical wiring harness to side.

-- Remove the bolts -1 and 2-.

Fig 6: Identifying Bolts & Ignition Coils Electrical Harness Connectors

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-- Disconnect electrical harness connectors at ignition coils.

-- Press electrical wiring harness to side.

-- Remove all ignition coils using T40039.

Fig 7: Identifying Ignition Coil Puller T40039 Removing Ignition Coils

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-- Using 3122 B, remove spark plugs.

-- Check compression using V.A.G 1763.

-- Have a second technician press accelerator pedal completely and at the same time operate starter long enough until pressure increase no longer appears on tester.

Assembly is in reverse order of removal, note the following:

-- Install sparks plugs.

-- If electrical connectors were disconnected and the engine was started, then malfunctions have been stored in the engine control module. "Generate readiness code" in "Guided Functions" vehicle diagnostic tester.