11 78 540 Replacing left monitor sensor (N74)

WARNING: Scalding hazard!

Only perform this work after engine has cooled down.

Necessary preliminary tasks:

Check function of DME control unit
Turn off ignition
Remove REAR UNDERBODY PROTECTION

Remove heat shield (2) of the left side.

Fig 1: Identifying Heat Shield

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Release exhaust system (1) at the catalytic converters.

Remove (2) sealing ring.

Fig 2: Identifying Exhaust System And Sealing Ring

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Release screws (1).

Remove exhaust holder (2).

Tightening torque: see 3AZ in 18 31 EXHAUST SYSTEM

Fig 3: Identifying Exhaust Holder With Screws

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Unclip plug connection (2) of the oxygen sensor from the holder (1).

Release oxygen sensor cable (3) from the retaining clips (4).

Disconnect plug connection of the oxygen sensor (2).

Fig 4: Identifying Oxygen Sensor, Cable, Plug Connection, Holder And Retaining Clips

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Detach oxygen sensor cable (1) from the retaining clips (2).

Fig 5: Identifying Oxygen Sensor Cable And Retaining Clips

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Release monitoring sensor (1) with special tools 11 7 030 and 11 9 150.

Fig 6: Releasing Monitoring Sensor Using Special Tools 11 7 030 And 11 9 150

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Installation:

The threads of new lambda control/monitoring sensors are already coated with Never Seez Compound (refer to BMW Parts Department).

If a lambda control/monitoring sensor is to be reused, apply a thin and even coating of Never Seez Compound to the thread only.

The part of the lambda control/monitoring sensor which projects into the exhaust branch (sensor ceramics) must not be cleaned and not coated with lubricant.

Fasten monitoring sensor (1) with special tools 11 7 030 and 11 9 150.

Installation:

When special tool 11 9 150 is used in conjunction with special tool 11 7 030, 47 Nm on the torque wrench dial corresponds to an actual tightening torque of 50 Nm.

Tightening torque: see 1AZ in 11 78 EMISSIONS CONTROL, CONTROL SENSOR / MONITORING SENSOR

Fig 7: Tightening Monitoring Sensor Using Special Tools 11 7 030 And 11 9 150

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Installation:

Check function of DME control unit.

Pay attention to cable routing of monitor sensor.