1997 BMW 528i Car engin

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I Airbag System (SRS)
Two-stage airbag (MRS Ill)
Beginning with 2000 model year (911 999 production) the front
airbags were changed to a two-stage style airbag. This en-
sures that the force of
airbag inflation is not greater than nec-
essary to provide
protection. The airbags are designed to
Drovide "soit" de~lovment if the acceleration sensor detects a
iow-speed impact, and "hard deployment in higher speed im-
pacts.
NOTE-
A two-stage passenger airbag was used on cars built be-
tween
9/1998 and 3/1999. This pre-smart technology airbag
used two ignition stages. Stage one is designed to ignite first
during an impact. Stage two ignites after a timed period, as
programmed in the MRS
I1 control module.
Airbag indicator light
The MRS control module detects and stores system status
The
airbag indicator light in the instrument cluster displays
the status of the
airbag system when the ignition key is in "ac-
cessory" or
ON positions.
System normal: lndicator light comes on briefly, then goes
out.
- System malfunction: lndicator light fails to come on.
System malfunction: lndicator light comes on briefly, goes
out and lights up again.
The
airbag indicator light also comes on if the seat belt pyro-
technic tensioners have been triggered.

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Airbag System (SRS)~
Warnings
When servicing airbag equipped cars, the following precau-
tions must be
observed to prevent personal injury.
WARNING-
. If the airbag indicator light is on, there is a risk that the air-
bags will not be triggered in case of an accident Be sure
to have the system inspected and repaired immediately
Airbag(s) are inflated by an explosive device. Handled
improperly or witliout adequate safeguards, the system
can be very dangerous. Special precautions must be
observed prior to any work at or near the airbags.
0 The airbag is a vehicle safety system. Serious injury
may result if system service is attempted by persons
unfamiliar with the BMW
MRS and its approved service
procedures. BMW advises that all inspection and ser-
vice be performed by an authorized BMW dealer.
Always disconnect the battery and cover the negative
(-) battery terminal with an insulator before starting di-
agnostic, troubleshooting or service
work not associat-
ed
with the airbags, and before doing any welding on
the car.
0 After disconnecting the battery, wait 5 seconds before
beginning work on
airbag components.
* If an airbag has been activated due to an accident,
BMW specifies that
airbag components be replaced.
For more information on post-collision
airbag service,
see an authorized BMW dealer.
Do not fire an
airbag unit prior to disposal. It must be
fired by a special disposal company or shipped back to
BMW in the packaging of the new components.
When removing a fired
airbag unit, avoid contact with
the
skin; weargloves. In case ofskin contact, wash with
water.
Do not allow
airbag system components to come in
contact with cleaning solutions or grease. Never sub-
ject
airbag components to temperatures above 167°F
(75°C). When reconnecting the battery, no person
should be inside the vehicle.
Always place an
airbag unit that has been removed
from its
packaging with the paddedside facing upward.
Do not leave an
airbag unit unattended.
0 If the airbag unit or airbag control module has been
dropped from a height of
'/? meter (I//: ft.) or more, the
airbag unit should not be installed.

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Airbag System (SRS)~
MRS control module, replacing
- Disconnect negative (-) cable from battery and cover nega-
tive terminal with insulating material.
CAUTIOI\C
Prior to disconnecting the battery, read the battery discon-
nection cautionsgiven in001 General Warnings and
Cau-
tions.
- Remove center console between front seats. See 513 lnteri-
or Trim.
Remove module mounting nuts (arrows) and lift up control
module. Disconnect electrical harness connector.
Installation is reverse of removal.
Be sure that MRS control module ground cable is attached
to the module mounting stud.
Side-impact crash sensor, removing and
installing
- Make sure ignition key is OFF.
- Remove front seat. See 520 Seats.
Remove plastic door sill trim by lifting to release clips at one
end, then sliding off. Fold up carpet towards rear seat floor. If
necessary, remove floor level heater duct.

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721 -9
Airbaq System ~SRS)~
4 Sport steering wheel:
Insert screwdriver through opening in rear of steering
wheel and push against spring tension to release
airbag
unit lock.
Repeat procedure on other side of steering wheel.
Lift off
airbag unit and detach electrical harness connec-
tors.
WARNING-
Store the removedairbag unit with the horn pad facing up.
If stored facing down, accidental deployment could propel
it violently into the air, causing injury.
Once an
airbag is removed, the car must not be driven.
Do not connect the battery with the
airbag disconnect-
ed. A fault code will be stored, setting off the
airbag in-
dicator light Special tools are needed to reset the fault
memory
Once the
airbag unit is installed and all other service
procedures have been completed, start the engine and
check that the
airbag indicator light goes out. If the in-
dicator light stays on, the
airbag system will not func-
tion as designed. Have the system diagnosed and
repaired by an authorized
BMW dealer.
- Installation is reverse of removal.
MFL steering wheel: Torque airbag using specification list-
ed below.
- Sport steering wheel: Press airbag unit mounting pins into
spring
loclts in steering wheel until they snap in firmly.
CAUTION--
Do notpinch airbag harness in center of steering wheel when
installino
airbaa.
Tightening torque
Airbao to steerino wheel IMFL) 8 Nm (71 in-lb)
Passenger airbag, removing and installing
- Disconnect negative (-) cable from battery and cover nega-
tive terminal with insulating material.
--
WARNING -
After disconnecting the batteg wait 5 seconds before begin-
nina work on airbaa components.
Prior to disconnecting the battery, read the battery discon-
nection cautionsgiven in001 General Warnings and
Cau-

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OBD On-Board Diagnostics
I I
General ........................... OBD-1 Diaqnostic Trouble Codes (DTCs) . . OBD-9
On-Board Diagnostics (OBD I!) ..... OBD-I
Malfunction Indicator Light (MIL)
........ OBD-2
Scan tools and scan tool display.
........ OBD-3
Diagnostic monitors
.................. OED-4
Drive cycle
......................... OED-6
Readiness codes
.................... OBD-6
Diagnostic trouble codes
(DTCs) ........ OBD-7
-
Automatic transmission diagnostic
trouble codes
....................... OBD-9
Engine diagnostic trouble
codes: M52 engine.
................. OED-13
Engine diagnostic trouble
codes: M54 engine.
................. OBD-17
Engine diagnostic trouble
codes: M62 engine.
................. OBD-24
This chapter outlines the fundamentals and equipment
requirements of On-Board Diagnostics
I1 (OBD 11) standards
as they apply to BMW vehicles. Also covered here is a listing
of BMW and OBD
I1 diagnostic trouble codes (DTCs).
ON-BOARD DIAGNOSTICS (QBD !I)
OBD II standards were developed by the SAE (Society of
Automotive Engineers) and CARB (California Air Resources
Board).
OED I1 is the second generation of on-board self-
diagnostic equipment requirements. These standards were
originally mandated for California vehicles. Since
1996 they
have been applied
toall passengervehicles sold in the United
States.
On-board diagnostic capabilities are incorporated into the
hardware and soflwareof the enginecontrol module
(ECM) to
monitor virtually every component that can affect vehicle
emissions. The
OED I1 system works to ensure that
emissions remain as clean as possible over the life of the
vehicle.
Each emission-influencing component is checked by a
diagnostic routine (called a monitor) to verify that it is
functioning properly.
If a problem or malfunction is detected,
the
diagnostic executive built into the OBD I1 system
illuminates a malfunction indicator light (MIL) on the
instrument panel.
The OBD
I1 system also stores diagnostic trouble codes
(DTCs) about the detected malfunction in the ECM so that a
repair technician can accurately find and fix the problem.

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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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OBD-3
On-Board
~iactnosticsl
Additional MIL information:
A fault code is stored within the ECM upon the first
occurrence of a fault in the system being checlted.
Two complete consecutive drive cycles with the iault
present illuminate the MIL. The exception to the two-fault
requirement is a catalyst-damaging fault, which illuminates
the MIL immediately.
If the second drive cycle was not complete and the fault
was not checked, the ECM counts the third drive cycle as
the next consecutive drive cycle. The MIL illuminates
if the
system is checked and the fault is still present.
Once the MIL is illuminated, it remains illuminated until the
vehicle completes three consecutive drive cycles without
detecting a fault.
0 An existing fault code is cleared from memory
automatically when the vehicle completes
40 consecutive
drive cycles without the fault being detected.
In order to automatically clear a catalyst-damaging fault from
memory, the condition underwhich the fault occurred must be
evaluated for 80 consecutive drive cycles without the fault
reoccurring.
A generic scan tool connected to the BMW data link
connector (DLC) or OBD
I1 plug can display diagnostic trouble
codes (DTCs), along with the conditions associated with the
illumination of the MIL. Using a more advanced or
BMW-
dedicated scan tool, additional proprietary information is
normally available.
Scan tool and scan tool display
The complexity of the OBD I1 system requires that all
diagnostics begin by connecting a scan tool to the vehicle.
Aftermarltet scan tools can be connected to either the 16-pin
OBD
I1 plug or the 20-pin BMW DLC in the engine
compartment
(ii installed). Data from the OBD II plug may be
limited, depending on scan tool and vehicle.
OBD
I1 standards reouire that the 16-oin OBD I1 oluo be
located within three
(3) feet of the driier and not're&ire any
tools to access.
Starting with June 2000 production, the 20-pin BMW DLC,
previously located in the engine compartment, was
discontinued. Diagnostic, coding and programming functions
are incorporated into the OBD
II plug, located under left side
of dashboard.
On cars built up to 06
/ 2000: when accessing emissions
related DTCs through the 16-pin OBD
I1 plug, malte sure the
BMW 20-oin DLC
caD is installed.

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OBD-6
On-Board Diagnostics
Fuel system monitoring. This monitor looks at the fuel
delivery needed (long
/short term fuel trim) for proper engine
operation based on programmed data. If too much or not
enough fuel is delivered over a predetermined time, a DTC is
set and the MIL illuminates.
Fuel trim refers to adiustments to base fuel schedule.
Lono- ., term fuel trim refers to gradual adjustments to the fuel
calibration adjustment as compared to short term fuel trim.
Long term fuel trim adjustments compensate for gradual
changes that occur over time.
Fuel system monitoring monitors the calculated injection time
(ti) in relation to enginespeed, load and precatalyticconverter
oxygen
sensor(s) signals.
Using this data, the system optimizes fuel delivery for all
engine operating conditions.
Evaporative system monitoring. This monitor checks the
the fuel storage system and related fuel lines for leaks. It can
detect very small leaks anywhere in the system.
A leak detection unit (LDP or DMTL) is used to pressurize the
evaporative control system on a continuous basis (as the
drive cycle allows) and to
check system integrity.
Drive cycle
The OED II drive cycle is an important concept in
understanding OBD
II requirements. The purpose of the drive
cycle is to run ail of the emission-related on-board diagnostics
over a broad range of driving conditions.
A drive cycle is considered complete when all of the
diagnostic monitors have run their tests without interruption.
~ora drive cycle to be initiated, the vehicle must be started
cold and brought up to
1 60°F and at least 40°F above its
original starting temperature.
Readiness codes
Inspection/maintenance (I/M) readiness codes are mandated
as part of OBD
II. The readiness code is stored aftercomplete
diagnostic monitoring of specified components and systems
is carried out. The readiness code function was designed to
prevent manipulating an
I/M emission test procedure by
clearing faults codes or disconnecting the ECM or battery.