Compression Pressure, Checking: Procedure

Engine oil temperature: minimum 30 °C (86 °F)
Battery voltage minimum 12.5 V.

-- Remove the rear noise insulation -2-. Refer to NOISE INSULATION .

Fig 1: Automatic Transmission Fluid Oil Pan

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-- Disconnect the connector -2- from the Engine Speed Sensor -G28-.

Fig 2: Disconnect Connector From Servotronic Solenoid Valve

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NOTE:

Ignore item -1-.

-- Remove the air duct -arrows-.

Fig 3: Identifying Air Duct

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-- Free up the fuel line and the line to the Evaporative Emission (EVAP) canister on the air guide pipe.

-- Disconnect the connector -1- from the Mass Airflow Sensor -G70-.

Fig 4: Disconnecting Connector On Mass Airflow (MAF) Sensor

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-- Disconnect the vacuum line -3- from the air guide pipe.

CAUTION:

Risk Of Violating Emissions Legislation On USA Vehicles.

Do not open hose connection -2- !

-- Lay aside air guide pipe with connected crankcase ventilation hose -2- by loosening hose clamp -4- and opening clips -arrows-.

-- Disconnect the vacuum line -1-.

Fig 5: Identifying Secondary Air System Components

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-- Remove the air filter housing and disconnect the electrical connector -2- on the rear side at the Intake Air Switch-Over Valve -N335-.

-- Remove hose -3- from the Secondary Air Injection (AIR) system.

-- Disconnect the coolant hose from -3- from the coolant overflow reservoir.

Fig 6: Identifying Coolant Hose And Coolant Reservoir

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-- Remove the bolts -arrows-.

-- Disconnect the connector on the Engine Coolant Level Warning Switch -F66- and move the coolant overflow reservoir with the coolant hoses -1 and 2- still connected to the side.

-- Pull the oil dipstick -1- out of the guide tube.

Fig 7: Identifying Oil Dipstick, Bolts & Ignition Coils Electrical Harness Connectors

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-- Remove the bolts -2 and 3-.

-- Disconnect the connectors on the ignition coils.

-- Press the electrical wiring harness to the side.

-- Remove the bolts -1 and 2-.

Fig 8: Identifying Bolts & Ignition Coils Electrical Harness Connectors

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-- Disconnect the connectors on the ignition coils.

-- Press the electrical wiring harness to the side.

-- Remove all the ignition coils in direction of -arrow- using the :T40039 .

Fig 9: Identifying Ignition Coil Puller T40039 Removing Ignition Coils

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-- Remove spark plugs with :3122B .

-- Check the compression using the :VAG1763 .

NOTE:

For Information On Using The Tester. Refer To The Operating Instructions.

-- Have a second mechanic press the accelerator pedal down all the way while operating the starter until the pressure increase is no longer displayed on the tester.

-- Repeat Procedure On Each Cylinder.

Compression Pressure	Pressure
New	10 to 14 bar (145 to 203 psi)
Wear limit	9 bar (130 psi)
Maximum difference between cylinders	3 bar (43 psi)

Assemble in reverse order of disassembling. Note The Following:

-- Install the spark plugs. Refer to

-- Install the rear noise insulation. Refer to NOISE INSULATION .

There will be faults stored in the engine control module Diagnostic Trouble Code (DTC) memory because the connectors were disconnected.

-- Generate Readiness Code in Guided Functions . Refer to Vehicle Diagnostic Tester.