Oxygen Sensors; Oxygen Sensors (Precatalyst), Replacing (M52 Tu And M54); Oxygen Sensors (Post-Catalyst), Replacing (M52 Tu And M54) - BMW 5251 Service Manual

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Exhaust System
Oxygen sensors (precatalyst), replacing
(M52 TU and M54)
The precatalyst oxygen sensors are installed at the top of the
exhaust manifolds.
WARNING-
Allow components to cool before servicing.
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Using BMW scan tool DlSplus (Diagnostic Information Sys-
tem) or equivalent, read out and clear ECM fault codes.
Working at right side of engine above exhaust manifolds,
remove front or rear oxygen sensor harness connector
(arrows) from bracket, then separate plug.
NOTE-
In photo, secondary air pump has been removed for clarity.
Remove oxygen sensor using special oxygen sensor
removal socket.
Installation is reverse of removal
New sensor threads come coated with anti-seize paste.
If reusing a sensor, apply thin coat of anti-seize paste to
threads only. Do not contaminate tip of sensor with paste
or lubricants of any sort.
Install harness and connector in original location.
Tightening torque
-
- .
Oxygen sensor to manifold
50
Nm (37
ft-lb)
Oxygen sensors (post-catalyst), replacing
(M52 TU and M54)
The post-catalyst oxygen sensors are installed at the rear of
the catalytic converters.
WARNING-
Allow components to cool before servicing
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Using BMW scan tool DlSplus or equivalent, read out and
clear ECM fault codes.
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Remove large cover from above fuel raillintake manifold.