ECT BMW 528i 1998 E39 Workshop Manual

Downloaded from www.Manualslib.com manuals search engine
721 -1 0
/Airbag System (SRS)
4 Pry up cover from top of passenger side airbag on dash-
board.
4 Remove airbag mounting bolts (arrows)
- Lift airbag and disconnect electrical harness connector. Re-
move
airbag.
WARNING-
Store the removed airbag unit with the soft pad facing up. If
stored facing down, accidental deployment could propel it vi-
olentlv into the
ail: causino inium
- Installation is reverse of removal. Make sure wiring harness
is not pinched when installing
airbag unit in dashboard.
Tightening torques
-
Passenger alr bag to 10 NM (88 in-lb)
dashboard (Me)
Door mounted side-impact airbag,
removing and installing
- Disconnect negatlve (-) cable from battery and cover nega-
tive terminal with insulating material.
CAUTION-
Prior to disconnecting the battea read the battery discon-
nection cautions given
in 001 General Warnings and Cau-
tions.
- Remove inside door panel as described in 41 1 Doors

Downloaded from www.Manualslib.com manuals search engine
721 -1 1
Airbag System (SRS)~
Front door airbag:
Remove airbag mounting bolts (arrows).
Disconnect electrical harness connector.
CAUTIOI\C
When removing andinstalling the airbag unit, pay attention to
the routing
of the electrical harness to avoid kinks or breaks
in the wire.
Installation is reverse of removal,
Rear door
airbag:
Detach electrical harness connector.
Remove mounting bolts and remove
airbag from door.
- Installation is reverse of removal.
Route electrical harnesses as they were before.
Use new wire ties as necessary.
Use new self-locking mounting bolts.
Tightening
torque
Side-impact airbag to door 8.5 Nm (75 in-lb)
Head protection airbag
components
1. B-pillar deflection plate
2. Head protection airbag
3. Cable holder
4. Gas generator

Downloaded from www.Manualslib.com manuals search engine
721-12
Airbag System (SRS)
Head protection airbag (HPS)
4 Replacement of a head protection airbag (HPS) is an exten-
sive operation, including removal of the following:
Complete dashboard
Complete headliner
Windshield pillar (A-pillar) trim
Door pillar (B-pillar) trim
- Before starting work on the HPS airbag, disconnect negative
(-) cable from battery and cover negative terminal with insu-
lating material.
Prior to disconnecting the battery, read the battery discon-
nection cautionsgiven in001 General Warnings and Cau-
tions.
Tightening torque HPS
airbag to body 11 Nm (8 ft-lb)
HPS airbag mounting bracket
to A or B-pillar
HPS gas generator to
dashboard reinforcement
(M6
self-tapping screw) 2.5
Nm (22 in-lb)
4 Nm (35 in-lb)

Downloaded from www.Manualslib.com manuals search engine
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.

Downloaded from www.Manualslib.com manuals search engine
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.

Downloaded from www.Manualslib.com manuals search engine
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.

Downloaded from www.Manualslib.com manuals search engine
- -
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.

Downloaded from www.Manualslib.com manuals search engine
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.

Downloaded from www.Manualslib.com manuals search engine
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.

Downloaded from www.Manualslib.com manuals search engine
On-Board Diagnostics
Readiness codes indicate whether the OED Ii system is
actually ready to monitor the various emission control
systems on the vehicle. The vehicle must complete a drive
cycle to set readiness codes. The code is binary:
0 for ready
1 for not ready
f
4 The parameters which are monitored for readiness are:
llM readiness codes
1. Catalyst efficiency
2. Catalyst heating
3. Fuel tank evaporative control
4. Secondary air injection
5.
NC refrigerant
6. Oxygen sensors
7. Oxygen sensor heaters
8. Exhaust gas recirculation
Readiness codes are set to 1 (not ready) in the following
cases:
~9~~.f~[<+t~t~p:,~;:#j~~{]~y~ ,,... , , 8701Dbd001
The battery or ECM is disconnected.
When
all zeros are displayed, the system has established
DTCs are erased after completion of repairs and a drive
cycle is not completed.
readiness. Readiness codes
can be displayed using BMW
and aftermarket scan tools.
An
OED II scan tool can be used to determine IIM readiness.
Diagnostic trouble codes (DTCs)
SAE standard J2012 mandates a 5-digit diagnostic trouble
code (DTC) standard. Each digit represents a specific value.
Emission related DTCs
start with the letter P for power train.
When the engine service
light (MIL) is illuminated it indicates
that a DTC has been stored.
DTCs are stored as soon as they occur, whether or not the
engine service light illuminates.
DTCs store and display a time stamp.
DTCs record the current fault status: Present, not currently
present, or intermittent.