11 00 039 Checking Compression Of All Cylinders (S85)

Special tools required: 

• 11 0 224
• 11 0 235

Disconnect all supply leads from ignition coils (interrupt power supply to ignition coils).

Check Schrader valve on special tool 110 235 for correct seating (engine damage).

The throttle valves cannot be opened by opening the throttle.

A compression check is carried out exclusively by means of the idle actuators.

A compression check is only possible with the diagnosis tester.

Necessary preliminary tasks: 

• Remove microfilter housing. See 64 31 061 REMOVING AND INSTALLING/REPLACING LEFT OR RIGHT MICROFILTER HOUSING LOWER SECTION or 64 31 061 REMOVING AND INSTALLING/REPLACING LEFT OR RIGHT MICROFILTER HOUSING LOWER SECTION (M6) .
• Release coolant tank and place to one side
• Remove all spark plugs.
• Connect diagnosis tester.

1. Service function.
2. Drive.
3. Engine electronics
4. Switch off fuel injection.
   IMPORTANT: Fuel injectors are switched off.
5. Actuate starter motor for 8 seconds.

Screw special tool 110 235 into spark plug hole.

Check that sealing ring is in perfect condition on special tool 11 0 235.

Connection (1) for diagnosis tester or special tool 11 0 224.

Connect special tool 110 224 or 25 bar pressure adapter to diagnosis tester.

Compression pressure.

Now clear the fault memory.