ecm BMW 528i 1998 E39 Owners Manual

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170-5
Radiator and Cooling System
Fan switch calibration (M52, M62 engine)
coniprairoi OUt rlgnal
Auto. ciimilte ~ontioi inpuls via CAN bus
Electric fan activation:
Low speed
91°C (196°F)
High speed 104' C (21 9' F)
< In models manufactured after 911998 (M52 TU engine, M54
engine.
M62 TU engine), the electric cooling fan is controlled
by the engine control module (ECM) via the output final
stage.
The output final stage is mounted on the fan housing, next to
the fan motor. The fan is operated using a pulse width modu-
lated signal. Fan circuit wiring is protected by a 50-amp fuse.
Electric fan activation is based on the following inputs to the
ECM:
Radiator outlet temperature
Calculated catalytic converter temperature
Vehicle speed
* Battery voltage
Calculated
A/C pressure
When the vehicle is first started, the ECM activates the elec-
tric fan briefly at 20% of its maximum speed, then switches
off. This is for diagnostic monitoring. The voltage generated
by the fan when it slows down (acting as a generator) must
match the stored rpm values in the fan output stage toconfirm
that the fan is operating correctly.
NOTE-
If the ECM fault memory indicates a cooling fan fault, check
that the fan is not seized and that it spins freely.
When
A/C is switched ON, the electric fan is not immedi-
ately turned on.
After the engine is switched
OFF the fan may continue to
run at varying speeds for up to 10 minutes, based on cal-
culated catalyst temperature.
Transmission fluid heat exchanger
Automatic transmission fluid lines circulate transmission fluid
(ATF) to and from a heat exchanger at the radiator.
All 6-cylinder
models andV-8 models produced to 911998 are
equipped with a transmission cooler located in a cooling cas-
sette in front of the radiator.

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Warnings and cautions
Obse~e the following warnings and cautions when worlting
on the cooling system.
WARNING -
. At normal operating temperature the cooling system is
pressurized. Allow the system to cool as long as possible
before opening (a minimum of one hour), then release the
cap slowly to allow safe release ofpressure.
a Releasing the coolant system pressure lowers the cool-
ant boilingpoint and the coolant may boil suddenly. Use
1 heavy and wear eye and face protection to
guard against scalding.
Use extreme care when draining and disposing of en-
gine coolant. Coolant is poisonous and lethal to hu-
mans andpets. Pets are attracted to coolant because
of its sweet smell and taste. Seek medical attention im-
mediately if coolant is ingested.
CAUTIOG
Avoid adding cold water to the coolant while the engine is
hot or overheated. If it is necessary to add coolant to a
hol
system, do so only with the engine running and coolanl
pump turning.
To avoid excess silicate gel precipitation in the cooling
system and loss of cooling capacity, use BMW coolant
or equivalent low silicate antifreeze.
a If oil enters the cooling system, the radiator, expansion
tank and heating circuit must be flushed with cleaning
agent. BMW recommends removal of the radiator and
expansion
tank to flush.
When
worlcing on the cooling system, cover the alter-
nator to protect it against coolant drips.
Prior to disconnecting the battery, read the battery dis-
connection cautions given in
001 General Warnings
and Cautions.
Begin the diagnosis of cooling system problems with a thor-
ough visual inspection.
If no visual faults are found, it is rec-
ommend that the engine control module (ECM) fault memory
be checked for stored diagnostic trouble codes
(DTCs) using
BMW scan tool
DlSplus or equivalent.

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170-8
I Radiator and Cooling System
Common cooling system faults can be grouped into one of 4
categories:
Cooling system
lealts
Poor coolant circulation
Radiator cooling fan faults
Electrical/electronic faults
Cooling system inspection
- Check that coolant pump drive belt tensioner is functioning
properly and that belt tension is correct. Belt tensioner sys-
tems for the different models are shown in
020 Maintenance.
- Check condition of coolant pump drive belt.
- Checlc coolant hoses for cracks or softness. Checlc clamps
for looseness. Check coolant level and check for evidence of
coolant
lealts from engine.
- Check that radiator fins are not blocked with dirt or debris.
Clean radiator using low-pressure water or compressed air.
Blow outward, from engine side out.
- To check coolant pump:
Remove mechanical cooling fan. See Mechanical
(vis.
cous clutch) cooling fan, removing and installing.
Remove drive belt from coolant pump pulley. See
020
Maintenance.
Firmly grasp opposite sides of pulley and check for play in
all directions.
Spin pulley and check that shaft runs smoothly without
play.
NOTE-
The coolant provides lubrication for the pump shaft, so an oc-
casional drop of coolant
lealing from the pump is acceptable.
If coolant drips steadily from the vent hole, replace the pump.
- At normal engine operating temperature, cooling system is
pressurized. This raises boiling point of coolant.
Leaks may
prevent system from becoming pressurized. If visual evi-
dence is inconclusive, pressure test cooling system as de-
scribed later to help pinpoint hard-to-find leaks.
- If cooling system is full of coolant and holds pressure:
- Use an appropriate scan tool to interrogate engine control
module (ECM) for radiator fan or DME control circuit faults.
Checlc for loose or worn drive belt.
0 Test for failed thermostat or coolant pump impeller. Some
pumps may be fitted with plastic impellers.

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Radiator and Cooling systeml
Tightening torques
Block drain plug to block 25 Nm
(18
it-lb)
Coolant hose clamp (32 - 48 2.
5 Nm (22 in-lb)
mm hose diameter)
Radiator drain plug to radiator
2-3Nm(l8-27in-lb)
Thermostat housing to cylinder
head 10 Nm (89 in-lb)
I Coolant thermostat housing assmbly- - I
Thermostat, removing and installing
(M52 TU or M54 engine)
4 The electric map-controlled thermostat is part of the thermo-
stat housing at the front of the cylinder head.
1. Bolts (M6)
2 Bolt (ME)
3. Housing with thermostat
4. Gasket
- If a faulty thermostat is suspected, use appropriate scan tool
to interrogate
ECM for stored fault codes.
- Drain radiator and engine block. See Coolant, draining and
filling (6-cylinder models).
CAUTION-
Allow cooling system to cool before opening or draining the
system.
- Remove cooling fan and fan shroud. See Mechanical (vis-
cous clutch) cooling fan, removing and installing.
- Disconnect electrical harness connector from thermostat
housina.
4 Lever out retaining clips (arrows) and pull hose fittings off
thermostat housing.
- Unbolt and remove thermostat housing from front of engine.
Loosen nut at top of engine lifting eye to facilitate removal.
- Installation is reverse of removal, noting the following:
Keep sealing faces free of oil.
* Use new sealing gasket.
When reinstalling hose to thermostat housing, install clip
on hose end fitting, then push hose onto housing until it
clicks into place.
Fill system with coolant. See Coolant, draining and fill-
ing (6-cylinder models).

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Tightening torques Block drain plug to block
25 Nm (18 ft-lb)
Radiator drain plug to radiator 2 - 3 Nm (18 - 27 in-lb)
Thermostat housing to
cylinder head 10 Nm (89 in-lb)
Thermostat, removing and installing
(V-8 models)
The electrically-heated thermostat is an integral parl of the
thermostat housing. The operation of the thermostat is moni-
tored by the engine control module (ECM).
- If a faulty thermostat is suspected, use appropriate scan tool
to interrogate ECM for stored fault codes.
- Drain radiator and engine block. See Coolant, draining and
filling
(V-8 models).
WARNING -
Allow cooling system to cool before opening or draining the
system.
- Disconnect mass air flow (MAF) sensor electrical harness
connector. Remove air intake duct together with MAF sensor.
- Remove mechanical cooltng fan and fan shroud. See Me-
chanical (viscous clutch) cooling fan, removing and
in-
stalling.
Disconnect electrical harness connector (arrow) from ther-
mostat housing.
Remove coolant hose from thermostat housing.
NOTE-
M62 engine: Hose is clamped on.
M62 TU engine: Hose is attached with quick-disconnect fit.
ting. Remove clip to disconnect hose.

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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)

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Suspension, Steering and Brakes - ~enerail
The main components of the system are the wheel speed
(pulse) sensors, the
ABSIASC or ABSIDSC control module,
and the hydraulic control unit.
Traction control also comes into operation during decelera-
tion. Decelerating on snowy or icy road surfaces can lead to
rear wheel slip. If a rear wheel starts to drag or lock up, the
ASC system can limit the problem by adjusting throttle, fuel
injection and ignition timing.
4 A switch (arrow) on the center console is used to toggle the
ASC on or off.
NOJE-
Even with the ASC system turned off, if the ASC control mod-
ule senses a difference in wheel speed (one wheel spinning)
the
ASC system applies modulated braling force to the slip-
ping wheel until traction is regained. There is no override of
fuelinjection function.
The ASC system is designed to be maintenance free. There
are no adjustments that can be made. Repair and trouble-
shooting of the ASC system requires special test equipment
and knowledge and should be performed only by an autho-
rized
BMW dealer.
ABSIASC traction
I 1.
control system
Wheel speed sensor
Wheel speed pulse wheel
Brake disk
Brake caliper
ABSIASC hydraulic unit
Brake master cylinder
Pedal operated throttle valve
ASC controlled throttle valve
Engine control module (ECM)
Accelerator pedal
ABSlASC control module

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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.