oxygen sensor BMW 540i 2000 E39 Service Manual

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Exhaust System
M52 engine
(5281 1997-1 998)
1. Exhaust manifolds
2. Sealing washer
3. Plug
4. Gasket (manifold to cylinder
head)
5. Clamping sleeve
6. Post-catalytic converter oxygen sensor
7. Pre-catalytic converter oxygen
sensor
8. Hanger
9. Rear muffler
10. Vibration dampener
11. Center support bracket
12. Clamping sleeve
13. Front pipe with catalytic
converters
14. Hanger
15. Center muffler
16. Gasket (front pipe to manifold)

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I Exhaust System
M52 TU and M54 engines
(528i 1999-2000
and 525i 2001-2003)
1. Transmission bracket
2. Center support bracket
3. Front muffler
4. Clamping sleeve
5. Vibration dampener
6. Hanger
7. Rear muffler
8. Hanger
9. Center muffler
10. Oxygen sensors, post-catalytic
converter
11. Oxygen sensors, pre-catalytic
converter
12. Exhaust manifoldlcatalytic
converter assemblies

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Exhaust systeml
M54 engine
(5301 2001-2003)
Clamping sleeve
Front muffler Rear muffler
Hanger
Vibration dampener
Clamping sleeve
Center muffler
Hanger
Gasket (front pipe to manifold)
10. Exhaust
manifold/catalytic
converter assemblies
11. Oxygen sensors, post-catalytic converter
12. Oxygen sensors, pre-catalytic converter

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I Exhaust System
M62 engine
(540i 1997-1 998)
1. Right side catalytic converters
2. Support bracket
3. Support bracket
4. Center muffler
5. Hanger
6. Rear muffler
7. Clamping sleeve
8. Oxygen sensors, post-catalytic
converter
9. Oxygen sensors, pre-catalytic
converter
10. Left side catalytic converter
11. Sealing rings
12. Left front exhaust manifold
13. Left rear exhaust manifold
14. Gasket
15. Exhaust manifold, right front
16. Exhaust manifold, right rear

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Exhaust systeml
M62 TU engine
(540i 1999-2003)
1. Oxygen sensors, pre-catalytic
converter
(2)
2.
Oxygen sensors, post-catalytic
converter
(2)
3.
Hanger
4. Rear muffler
5. Clamping sleeve
6. Hanger
7. Center muffler
8. Clamping sleeve
9. Catalytic converter, left side
10. Catalytic converter, right side
11. Exhaust manifoldlcatalytic
converter,
left side
12. Gasket (2)
13.
Gasket (2)
14.
Exhaust manifoldlcatalytic
converter, right side

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--.
- - Manual Transmission
- V-8 engine: Remove heat shield from left front axle support.
< V-8 engine: Remove engine speed reference sensor from
transmission.
- Where applicable, remove brackets for transmission under-
body protection (adjacent to transmission).
4 Support transmission with transmission jack.
- Where applicable, remove reinforcing cross brace from
below driveshaft at transmission.
- Disconnect harness connector from back-up light switch
on transmission.
- Free harnesses for oxygen sensors and back-up lights
from crossmember and transmission.
Remove transmission crossmember: Remove transmission mount bolts
(A).
Remove transmission crossmember bolts (B)
Where applicable, remove bolts (C).
NOTE-
5-speed transmission shown in illustration. Crossmember
assembly for 6-speed transmission is similar.
Disconnect driveshaft from transmission and hang to one
side. See
260 Driveshaft.
I CAUTION- I
Do not damage constant velocity joint orprotective boot at
rear differential.
- 6-cylinder engine: Remove stabilizer bar links and swivel sta-
bilizer bar
u~wards.

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260-1 0
/ Driveshaft
Driveshaft, installing
- Prepare CV joint for reinstallation:
Extend joint to limit.
Clean off old grease and fill with fresh grease
Install new seal.
- Bend driveshaft slightly at center universal joint to install
CAUTION-
Do not allow CVjoint seal to become displaced.
- Align matchmarlts on driveshaft to matchmarks on final drive
and transmission flanges.
- Fit constant velocity joint to final drive input flange. Alternate-
ly tighten two opposite nuts to draw constant velocity joint
evenly into the final drive input flange. Once seated, tighten
down remaining nuts.
I CAUTION-
I Do not reuse self-locking nuts. These nuts are designed to be /
I used onlv once. 1
- Insert bolts in front of driveshafl to transmission output
flange. Counterhold each bolt while tightening nut.
CAUTION-
. Do not reuse self-locking nuts. These nuts are designed to
be used only once.
Avoid stressing the flex-disc when torquing the bolts.
Do this by counterholding the bolts and turning the nuts
on the flange side.
- Position center support bearing and install mounting nuts.
Use new self-locking nuts.
- Install heat shields.
- Install rear transmission support crossmember.
- Install exhaust system. See 180 Exhaust System.
Reconnect oxygen sensor wiring harnesses and reattach
wiring harness retainers to rear transmission support
crossrnernber.

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OED-2
On-Board Diagnostics
Specialized OED II scan tool equipment is needed to access
the fault memory and
OED I1 data.
The extra hardware needed to operate the OED
I1 system
consists mainly of the following:
* Additional oxygen sensors downstream of the catalytic
converters.
Fuel tank pressure sensor and device to pressurize
fuel
storage system.
Several engine and performance monitoring devices
Standardized 16-pin
OED II connector under the
dashboard.
Upgraded components for the federally required reliability
mandate.
Malfunction indicator light (MIL)
OED II software illuminates the malfunction indicator light
(MIL) when emission levels exceed 1.5 times Federal
standards.
4 For E34 cars covered by this manual, three different MIL
symbols were used, depending on year and model.
MIL illuminates under the following conditions:
Engine management system fault detected for
two
consecutive OED iI drive cycles. See Drive cycle in this
repair group.
- Catalyst damaging fault detected.
Component malfunction causes emissions to exceed 1.5
times OED
II standards.
Manufacturer-defined specifications exceeded. Implausible input signal.
Misfire
faults.
Leak in evaporative system,
Oxygen sensors observe no purge
flow from purge valve 1
evaporative system.
ECM fails to enter closed-loop operation within specified
time.
ECM or automatic transmission control
module (TCM) in
"limp home" mode.
ignition key ON before cranking (bulb
check function).
OED
II fault memory (including the MIL) can only be reset
using a special scan tool. Removing the connector from the
ECM or disconnecting the battery does not erase the fault
memory.

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- -
On-Board Diagnostics
Professional diagnostic scan tools available atthe time of this
printing include the BMW factory tools
(DISplus, GTI,
MoDiC) and a small number of aftermarket BMW-specific
tools. See
020 Maintenance.
In addition to the professional line of scan tools, inexpensive
generic OBD
II scan tool software programs and handheld
units are readily available. Though limited, they are
nonetheless powerful diagnostic tools. These tools read live
data streams and freeze frame data as well as a host of other
valuable diagnostic data.
Diagnostic monitors
Diagnostic monitors run tests and checks on specific
emission control systems, components, and functions.
A complete drive cycle is requiredforthe tests to bevalid. See
Drive cycle in this repair group. The diagnostic monitor
signals the
ECM of the loss or impairment of the signal or
component and determines if a signal or sensor is faulty
based on
3 conditions:
* Signal or component shorted to ground
Signal or component shorted to
B+
Signal or component missing (open circuit)
The OBD
II system monitors all emission control systems that
are installed. Emission control systems vary by vehicle model
and year. For example, a vehicle may not be equipped with
secondary air injection, so no secondary air readiness code
would be present.
OBD
II software monitors the following:
Oxygen sensors
Catalysts
Engine misfire
- Fuel tank evaporative control system
Secondary air injection Fuel system
Oxygen sensor monitoring. When driving conditions allow,
response rate and switching time of each oxygen sensor is
monitored. The oxygen sensor heater function is also
monitored. The OBD
II system differentiates between
precataylst and post-catalyst oxygen sensors and reads each
one individually. In order
forthe oxygen sensor to be
effectively monitored, the system must be in closed loop
operation.

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On-Board Diagnostics
Catalyst monitoring. Thisstrategy monitors the outputofthe
precatalyst and post-catalyst oxygen sensors, comparing the
oxygen content going into the catalytic converter to the
oxygen leaving the converter.
The diagnostic executive
lknows that most of the oxygen
should be used up during the oxidation phase. If it detects
higherthan programmed values, afault is set and the MIL
illuminates.
Misfire detection. This strategy monitors crankshaft speed
fluctuations and determines if an enoine misfire occurs bv
monitoring variations in speed between each crankshaft
sensortrigger point. This strategy is so finely tuned that it can
determine the severity of the misfire.
The system determines
if a misfire is occurring, as well as
other pertinent misfire
information such as:
Specific
cylinder(s)
Severity of the misfire event
Emissions relevant or catalyst damaging
Misfire detection is an on-going monitoring process that is
only disabled under certain limited conditions.
Secondary air injection monitoring. Secondary air
injection is used to reduce HC and CO emissions during
engine warm up. Immediately following a cold engine start
(-1 0" to 40°C), fresh air (and therefore oxygen) is pumped
directly into the exhaust
manifold. By injecting additional
oxygen into the exhaust manifold, catalyst warm-up time is
reduced.
Secondary air system components are:
Electric air injection pump
* Electric pump relay
* Non-return valve
Vacuum
I vent valve
- Stainless steel air injection pipes
Vacuum reservoir
The secondary air system is monitored via the use
of the pre-
catalyst oxygen sensors. Once the air pump is active and air
is injected into the system, the signal at the oxygen sensor
reflects a lean condition. If the oxygen sensor signal does not
change, a fault is set and the faulty
bank(s) identified. If after
completing the next cold startafault is again present, the MIL
illuminates.