oxygen sensor remove BMW 540i 2000 E39 User Guide

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.. .-
/Fuel lnjeciion
NOJE-
With engine oft disconnect harness connector and checlc
heating element resistance between white wires on the sen-
sor side of harness. If the element is electrically open (no
continuity), replace sensor.
- If oxygen sensor does not produce a fluctuating voltage and
preheater circuit is
OK, replace sensor.
NOJE-
If not already applied, coat oxygen sensor threads w~th anti-
seize compound before installat~on. Do not get the com-
pound on the sensor tip.
Tightening torque Oxygen sensor to exhaust system
55 Nm (41 ft-lb)
Fuel injectors, checking and replacing
The fuel iniectors are switched on and off (oaened and
closed)
by'the ECM. The injectors are connkcted to acom-
mon power source. A ground signal from the ECM is used to
open and close the injectors.
CA U JIOG
Use only a digital multimeter or an LED injector tester when
testing injectors or wiring. Use of an analog
VOM or incan-
descent test light may damaqe the engine controlmodule.
4 Remove fuel rail cover. See 110 Engine Removal and in-
stallation.
With the engine running, place the point of a long screwdriver
on each injector and check for a cliclting vibration.
If no vibra-
tion is found do the voltage
checit shown below.
Injector electrical loom removal:
- Loosen mounting nuts A.
Remove ground wire C.
Disconnect ignition coil harness D

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130-72
Fuel Injection
I Oxygen sensors, replacing
4 Four Bosch oxygen sensors (2 precatalytic converter sen-
sors and
2 post-catalytic converter sensors) provide a vary-
ing voltage signal
[0.2 vdc (max. lean) to 0.8 vdc (max. rich)]
to the ME
7.2 ECM representing oxygen content in the ex-
haust gas.
WARNING-
Exhaust manifolds and pipes can be hot enough to cause se-
rious burns. Wear suitable heavy gloves and other appropri-
ate protection.
- Using a special oxygen sensor socltet, remove the threaded
sensors from the exhaust system.
- If not already applied, coat the new oxygen sensor threads
with an anti-seize compound before installation. Do not get
compound on the sensor tip.
Tightening torque
Oxygen sensor to exhaust system
50 Nm (37 ft-lb)
Fuel injectors, removing and installing
The ME 7.2 system uses ball seat type fuel injectors. This de-
sign
prov:des precise seal'ng when the iniector is closed
therebv eiminalinq raw HC (unb~rned fue ) formalion in tne
intake.-~he fuel inkctors areswitched on and off by the ECM
at the ground side.
- Remove plastic cover from above fuel rail. See100 Engine
Removal and Installation.
- Disconnected battery negative (-) cable.
CAUTION-
Prior to disconnecting the battea read the battery discon-
nection cautions given at the front of this manual. See 001
General Warnings and Cautions.
- Remove both ignition coil covers.
Disconnect ignition coil connectors.
Remove left and right ignition coil ground wires,
4 Remove fuel injector loom boxes.
Loosen mounting fasteners
(A).
Disconnect electrical plugs (B and D).

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180-2
Exhaust System
The exhaust system is designed to be maintenance free, al-
though regular inspection is warranted due to the harsh oper-
ating conditions. Under normal conditions, the catalytic
converter does not require replacement unless it is damaged.
New fasteners, clamps, rubber mounts and gaskets should
be used when replacing exhaust components.
A liberal appli-
cation of penetrating oil to the exhaust system nuts and bolts
in advance may make removal easier.
WARNING -
The exhaust system and catalytic converter operate at
very high temperatures. Allow components to cool before
servicing. Wear protective clothing to prevent burns.
Do not use flammable chemicals near a hot
cataiyiic
converter.
Corroded exhaust system components crumble easily
and often have exposed sharp edges. To avoid injury,
wear eye protection and heavy gloves when working
Exhaust system, removing and installing
The removal and installation procedures given here are gen-
eral procedures for all models. The removal of the exhaust
system as a complete unit is recommended. Once the com-
plete system is removed from the car, individual pipes and
mufflers can be more easily replaced.
WARNING-
Exhaust gases are colorless, odorless, and very toxic. Run
the engine only in a well-ventilated area. Immediately repair
any
leaks in the exhaust system or structural damage to the
car body that
might allow exhaust gases to enter the passen-
ger compartment.
CAUTION-
Use care not to drag or bang oxygen sensors. Oxygen sen-
sors can be easily ruined.

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... .
Exhaust System
- With exhaust system fully cold, raise and support car for ac-
cess to exhaust system.
WARNING -
Do not worlc under a lifted car unless it is solidly supported on
jack stands designed for that purpose. Never work under a
car that is supported solely by a
jack.
- Disconnect oxygen sensor connector(s).
4 Loosen and remove bolts holding front exhaust pipes to ex-
haust manifolds (arrows). Right side of
V8 model shown.
- Support exhaust system
- Where applicable, disconnect exhaust support bracket as-
sembly from transmission.
< Remove hangers by prying off bracket (arrows).
- Lower exhaust system as a single unit to ground.
NOTE-
If the catalytic converterlfront exhaust pipe assembly is to be
replaced, transfer the oxygen sensors to the new
pipe(s).
Tightening torque
Oxygen sensor
55 Nm (41 ft-lb)
- installation is reverse of removal.
* Make sure there is at least 20 mm (314 in.) clearance be-
tween exhaust system and car body at every point.
Loosely install
ail exhaust system mounting hardware and
hangers before tightening fasteners to their final torque.
Coat manifold studs with copper paste before installing
nuts.
NOTE-
Where applicable, tighten front pipe with semi-flexible com-
pensator last when installing front pipe to
manifolds.
Tightening torques
Exhaust manifolds
to cylinder head 22 Nm (1 7 It-lb)
Front exhaust pipe to manifolds 30 Nm (22 ft-lb)
To prevent exhaust system rattles and vibration, the system
should be slightly preloaded by pushing the rear clamping
brackets forward about 7 mm (114 in).

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Exhaust system1
Exhaust manifold removal procedures are organized accord-
ing to engine code. If necessary, see
100 Engine-General
for engine code and application information.
Exhaust manifolds, removing and installing
(M52 engine)
4 Exhaust manifolds for the M52 engine.
Always use new retaining nuts and gaskets when removing
and installing the exhaust manifolds.
- With exhaust system cold, raise and support car for access
to exhaust system.
WARNING -
Do not work under a lined car unless it is solidly supported on
jack stands designed for that purpose. Never work under a
car that is supported solely by a jack.
- Disconnect secondary air check valve and pipe from exhaust
manifold.
- Unbolt front exhaust pipe@) from exhaust rnanifold(s)
- Remove exhaust support bracket from transmission.
- Loosen and remove nuts from exhaust manifolds and remove
manifolds. Discard nuts and gaskets.
NOTE-
On cars with oxygen sensors mounted in the exhaust mani-
folds, use care when removing manifolds.
To be safe, remove
the sensors from the manifolds before removing manifolds.
- Installation is reverse of removal
Coat exhaust manifold mounting studs with copper paste
before installing new nuts.
Install manifold gaskets with arched side facing manifolds.
Tightening torque
Exhaust manifolds
to cylinder head 20 Nm (15 ft-lb)

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180-6
Exhaust System
Exhaust manifolds, removing and installing
(M52 TU and M54 engines)
I Exhaust manifolds with converters I 4 The exhaust manifolds incorporate the catalytic converters.
Two precatalyst and two post-catalyst oxygen sensors are
mounted in the exhaust manifold assembly.
Under normal conditions, the catalytic converters do not re-
quire replacement unless damaged. Always use new retain-
ing nuts and gaskets when removing and installing the
exhaust manifolds.
I\
1 4 Using engine support equipment (BMW special tools 00 0
200. 00 0 201. 00 0 202.00 0 204.00 0 208 or equivalent).
connect to
lifting eye on front of engine. Rhise engine approx.
/I 1
5 mm (IH in).
With exhaust system cold, raise and support car for access
to exhaust system.
WARNING-
Do not worlc undera liftedcar unless it is solidly supported on
jack stands designed for that purpose. Never worlc under
a
car that is supported solely by a jaclc.
in order to avoid damaging oxygen sensors:
- Detach oxygen sensor harness connectors,
Remove oxygen sensors from exhaust manifolds as de-
scribed later in this group.
Unbolt and remove secondary air
checkvalve and pipe from
right front of cylinder headlexhaust manifold.
Working underneath car, unbolt front exhaust pipes from ex.
haust manifolds.
With engine supported from above, remove right engine
mount
bracket and right engine mount (arrow).
Loosen and remove nuts from exhaust manifolds and remove
manifolds. Discard nuts and gaskets.
CA UTIOG
Take care tliat the front and rear oxygen sensor connectors
are not mixed up.
-

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1 Exhaust ~vsteml
NOTE-
The front exhaust manifold must be removed before the rear
manifold.
- Installation is reverse of removal.
Coat exhaust mounting studs with CRC or equivalent cop-
per paste.
Use new gasltets and self-locking nuts.
Tightening torques Exhaust manifold to cylinder head 20 Nm
(15 ft-lb)
Front exhaust pipe to manifold 30 Nm
(22 ft-lb)
Oxygen sensor to manifold 50
Nrn (37 ft-lb)
Exhaust manifolds, removing and installing
(M62 engine)
Always use new retaining nuts and gasltets when removing
and installing the exhaust manifolds.
NOTE-
Access to manifolds is extremely limited. If removing exhaust
manifolds as part of additional engine worlc (such as cylinder
head removal), it may be easier to first remove engine.
- With exhaust system cold, raise and support car for access
to exhaust system.
WARNING -
Do not work undera lifted car unless it is solidly supported on
jaclt stands designed for the purpose. Never worlc undera car
that is supportedsolely
by a jack.
- Remove exhaust system. See Exhaust system, removing
and installing.
- Removing right side exhaust manifolds (cylinder bank 1-4):
Remove heat baffle plate.
Disconnect plug connection to oxygen sensor.
securing exhaust manifolds to head.
Remove manifolds towards bottom.
- Installation is the reverse of removal.
Coat exhaust mounting studs with CRC or equivalent
copper paste.
Use new gasltets and self-loclting nuts.

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- Removing left side exhaust manifolds (cylinder bank 5-8):
- Remove heat baffle plate on left side.
Remove oxygen sensor using
BMW special tool 11 7 030
or similar oxygen sensor socket.
Install
BMW special tools 00 0 200,OO 0 201,OO 0 202,OO 0
204, and 00 0 208 or other suitable engine lifting support
above engine and attach to lifting eye on left head.
NOTE-
The supports on special tool 00 0 208 must rest on the
screws on the fenders.
- Remove nut at top of engine support on left side
- Raise engine at front suspension lug a maximum of 25 mm
(I
.O in).
Release clamping bolt and nut
(arrow) and slide universal
joint off steering gear.
4 Remove nuts securing left exhaust manifold to head,
Raise front of manifold as high as possible past end posi-
tion of steering gear and feed out towards bottom.
- Installation is reverse of removal.
Coat exhaust mounting studs with CRC or equivalent
copper paste.
Use new exhaust gaskets and self-locking nuts.
Install new self-locking nuts on engine mount and steering
shaft bolt.

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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.
- 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
- Using BMW scan tool DlSplus or equivalent, read out and
clear ECM fault codes.
- Remove large cover from above fuel raillintake manifold.

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Exhaust System
Label and disconnect sensor harness connectors (arrows).
CAUTlOI\C
Label connectors so that front and rear connectors are not
mixed up.
- Detach harness from guides and brackets.
- Remove oxygen sensor from exhaust manifold using special
tool
11 7 030 or equivalent.
- Installation is reverse of removal
New sensor threads come coated with anti-seize paste.
If reusing old 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 sensor, replacing
(M52 and M62 engine)
The sensors are installed at the front and rear of the catalytic
converters.
I WARNING- I
I Allow components to cool before servicing. I
Using BMW scan tool DlSplus or equivalent, read out and
clear
ECM fault codes.
Detach harness from guides and brackets.
Remove oxygen sensors (arrows) from exhaust using spe-
cial tool
ll 7 030 or equivalent.
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
Oxvaen sensor to manifold 50 Nm (37 it-lb)