11 00 039 Checking compression at all cylinders

Special tools required:

NOTE: Read out fault memory of EMS/DME control unit, check stored fault messages, rectify faults and clear fault memory.

Switch off ignition.

CAUTION: High tension - danger!
Interrupt voltage supply to ignition coils.

Detach plug connector from ignition coil unit.

Fig 1: Detaching Plug Connector From Ignition Coil Unit

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Press securing clip (1) away.

Detach plug connector (2).

Unscrew all spark plugs. Refer to 12 12 011 REPLACING ALL SPARK PLUGS .

Screw special tool 11 8 490 into spark plug thread and connect special tool 11 0 224.

Fig 2: Identifying Special Tool

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Make sure seal of adapter tool is in proper working order.

Press accelerator pedal to floor and actuate starter motor until compression pressure stops rising.

Fig 3: Testing Compression

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Compression pressure, Refer to ENGINE - TECHNICAL DATA .

NOTE: Disconnect ignition unit; this results in a defect trouble code being output during starting.

Connect DIS and delete stored faults.

NOTE: Read out fault memory of EMS/DME control unit, check stored fault messages, rectify faults and clear fault memory.