Compression Check: Testing and Inspection

Compression, Measuring

Special tools, testers and auxiliary items required

• Spark plug removal tool (3122 B)

• Compression tester (V.A.G 1763)

• Ignition Coil Puller (T40039)

Work procedure

• Engine oil temperature at least 30 °C.

• Battery voltage at least 12.5 V.

- Switch off ignition.

- Remove Engine Control Module (ECM) (J623)

- Only remove smaller connector - 1 - from engine control module (ECM) by removing connector lock - arrow -.





• The larger connector - 2 - remains connected.

- Remove bolts - arrows -.





- Remove air duct - 1 and 2 -.

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





- Disconnect electrical harness connector - 1 - at Mass Air Flow (MAF) Sensor (G70).

- Remove vacuum line - 3 - to air guide hose.

CAUTION!
Risk of violating emissions legislation.

• Do not open hose connection - 2 -!

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

• Ignore - 5 -.

- Open clips - arrows - and remove upper part of air filter housing.





- Remove coolant reservoir - arrow - and disconnect electrical connector on Engine Coolant Level (ECL) Warning Switch (F66) at bottom of coolant reservoir.





- Lay aside coolant reservoir with connected coolant hoses - 1, 2, 3 -.

- Remove oil dipstick - 1 - from guide tube.





- Remove bolts - 2 and 3 -.

- Disconnect electrical harness connectors at ignition coils.

- Press electrical wiring harness to side.

- Remove bolts - 1 and 2 -.





- Disconnect electrical harness connectors at ignition coils.

- Press electrical wiring harness to side.

- Remove all ignition coils using Ignition Coil Puller (T40039).





- Remove spark plugs using Spark Plug Removal Tool (3122 B).

- Check compression using compression tester (V.A.G 1763).

• Using tester => operating instructions.

- 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.

- Install Engine Control Module (ECM) (J623)

Faults are saved in ECM when electrical connectors are disconnected:

- Connect Vehicle Diagnosis, testing & info. system (VAS 5051).

- Start "Guided Functions" operating mode.

- Generate readiness code in ECM.