Compression Check: Testing and Inspection

Compression, Checking

Special tools, testers and auxiliary items required

• Spark Plug Removal Tool (3122 B)

• Compression Tester (V.A.G 1763)

• Ignition Coil Puller (T40039)

Procedure






• Engine oil temperature at least 30 °C (86 °F).

• Battery voltage at least 12.5 V.

- Remove the rear noise insulation - 2 -.

- Disconnect the electrical connector - 2 - on the Engine Speed (RPM) sensor (G28).






• Ignore - 1 -.

- Remove the air duct - arrows -.






- Free up the fuel line and the line to the EVAP canister on the air guide pipe.






- Disconnect the connector - 1 - from the Mass Airflow (MAF) sensor (G70).

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


Risk of violating emissions legislation.

• 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 -.






- 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 system.

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






- Remove the bolts - arrows -.

- Disconnect the electrical connector on the engine coolant lever 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.






- Remove the bolts - 2 and 3 -.

- Disconnect the electrical connectors on the ignition coils.

- Press the electrical wiring harness to the side.

- Remove the bolts - 1 and 2 -.






- Disconnect the electrical connectors on the ignition coils.

- Press the electrical wiring harness to the side.

- Remove all the ignition coils with the (T40039).






- Remove the spark plugs using the (3122 B).

- Check compression pressure using the (V.A.G 1763).

• Using tester, see operating instructions.

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

- Repeat the procedure on each cylinder.






Assemble in reverse order of disassembling. Note the following:

- Install spark plugs.

- Install the rear noise insulation.

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

- Generate readiness code in Guided Functions using the vehicle diagnostic tester.