2000 BMW 528i Secondary air system

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Engine Removal and Installation
4 Working at E-box at right rear of engine compartment:
Disconnect engine electrical harness connectors
(arrows).
Lift off harness looms and lay over engine.
- Remove polyribbed drive belts. Mark direction of rotation if
belts will be reused. See 020 Maintenance.
- Remove exhaust system and transmission from car. See 180
Exhaust System, 230 Manual Transmission or 240 Auto-
matic Transmission.
NOJE-
Detach automatic transmission cooler lines from radiator, re-
move brackets holding lines to side of engine, andstore lines
in a clean environment.
- Remove power steering pump:
If necessary, remove steering pump pulley.
Remove front and rear pump mounting bolts.
Suspend pump from body using stiff wire.
4 Remove A/C compressor mounting bolts (arrows) and AIC
compressor from its mounting bracketwithoutdisconnecting,
distorting, or deforming any refrigerant lines. Suspend from
body using stiff wire.
4 If applicable, remove secondary air pump:
Remove hose at one-way valve
(A).
Remove bolts at support bracket on strut tower (arrows).
- Disconnect electrical harness from bottom of secondary
air pump.
Remove bracket from strut tower.

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Cylinder Head Removal and Installation
4 If applicable, remove secondary air injection pump:
Disconnect hose at one-way valve
(A).
Remove bolts at support bracket on strut tower (arrows).
Disconnect electrical harness from bottom of secondary
air injection pump.
Remove mounting bracket from strut tower.
4 Remove ignition coils:
* Disconnect ignition coil harness connectors.
Remove coil mounting fasteners.
Remove coils.
* Remove ground straps.
CA UTIOI\C
Note location of all ground wires. Failure to reinstall grounds
can result in permanent damage to engine control module or
ignition system components.
Set coil harness to side of engine compartment
- Remove cylinder head cover mounting fasteners and remove
cylinder head cover.
NOTE-
The cylinder head cover mounting bolt insulators and gas-
ltets should be reinstalled in their original locations. Male
note of their arrangement during removal.
- Remove spark plugs
4 Remove oil baffle cover from above intake camshaft.

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Ignition System
This repair group covers component troubleshooting and re-
placement information for the ignition system.
When diagnosing engine management problems, including
on-board diagnostics (OBD
11) fault code analysis, also refer
to these repair groups:
* 130 Fuel Injection
* ELE Electrical Wiring Diagrams
OED On-Board Diagnostics
Special tools
System diagnosis and testing of the ignition system requires
special test equipment.
4 LED test light
(Tool No. Baum
1 1 15)
4 Automotive digital multimeter
4 Primary voltage test harness
(Tool No. BMW 12
7 020)
-
4 Secondary voltage test harness
(Tool No. BMW 12
7 030)

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120-7
Ignition System
Spark plug electrode gap /Too small /TOO big
Table
b. Ignition secondary voltage diagnostics
Secondary
voltage low
Fuel air mixture
I I Too lean
Secondary
voltage high
Spark plug electrode
Worniburnt
4 The illustration shows normal scope trace of spark at idle.
1. Start of ignition voltage peak
2 Level of ignition voltage
3. Level of combustion voltage
4. Period of combustion
5. Combustion curve characteristics
6. Start of decay process
7. Termination oscillations
Spark plug electrode
temperature
Engine compression
Spark plug wires
4 Short combustion period (indicates large spark plug gap).
Too
high
Too
low
I"" 9, 10 I" to I!, r) i" 21 10 il bW,rn?7G
Too low
Too high
Faulty
4 Ignition spark at idle speed.
A - Normal ignition voltage peak (spark plug is good).
B - Low voltage peak is an indication of a closed plug gap.
C
- High voltage peak indicates an open plug gap.
< Long combustion period (indicates small spark plug gap).
~i,+i!,~,i~tiii~iit~~,t1!lc,',l~~4~l~,~,l,~+~{+',,l 1W W Sl ,@ 10 :o 9 20 21 10 0

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Ignition System
- Turn ignition on and check for battery voltage,
If battery voltage is not present,
checlt wire between termi-
nal
15 and the unloader relay. See ELE Electrical Wiring
Diagrams.
- Turn ignition off.
Remove coil and inspect coil housing for hairline
cracks or
leaking casting material. Replace any
cracked or leaking coil.
NOTE-
A leaky coil may indicate a faulty Engine Control Module
(ECM). Check ECM before installing a new coil.
CAUTION-
Note location of coilground straps before coil removal; rein-
stall in the same location.
Use a multimeter to test:
Coil primary resistance at coil terminals.
Sparlt plug connector resistance.
* Compare results to specification in Table c. lgnition coil
resistance.
Table c. Ignition coil resistance
Coil secondary
resistance
Spark plug connector:
Bosch 1 .O I( ohm t 20%
1.8 ir ohm t 20%
Component
Co~l prlmary
resistance
- Replace ignition coil or sparlt plug connector if resistance
readings do not meet specifications.
4 Remove ignition coil to be tested.
Install
BMW special tool 12 7 030 (A) on coil to be tested.
Connect ground jumper between coil mounting point
(B)
and engine ground point (C).
Clip scope high pick-up lead (D) around ignition lead.
Start engine.
Compare scope pattern with diagrams in Oscilloscope
di-
agnostic diagrams.
NOTE-
When replacing ignition coils, ensure that the replacements
Terminal
1 (-) and 15 (+)
are
from the same manufacturer with the same partlcode
numbers. If individual coils with the correct specifications are
not available. all coils should be
re~laced.
Resistance
0.8 ohms

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130-1
130 Fuel injection
General ........................... .I3 0.2
Tools and test equipment .............. .I3 0.3
Warnings and cautions ................ .I3 0.5
Fuel Supply ....................... .I3 0.6
Relieving system fuel pressure .......... .I3 0.6
Siemens MS 41 . 1. ................... 1 30-7
ECM relay. testing .................... .I3 0.7
Mass air flow (MAF) sensor.
checking and replacing
................ .I3 0.9
Engine coolant temperature (ECT) sensor.
testing and replacing
.................. 130-10
Intake air temperature (IAT) sensor.
testing and replacing
................. .I3 0.1 1
Throttle position sensor (TPS).
testing and replacing
.................. 130-1 2
ldle speed control valve.
checking and replacing
............... .I3 0.1 3
Fuel injectors. checking and replacing .... 130-15
Evaporative emissions. overview ....... .I3 0.1 6
Secondary air injection. overview ....... .I3 0-17
Engine control module (ECM).
removing and installing
................ 130-18
Siemens MS 41.1 ECM pin assignments . .I3 0.19
Siemens MS 42.0 and MS 43.0. ..... .I3 0.23
ECM relay. testing ................... .I3 0.27
Mass air flow (MAF) sensor.
checking and replacing
............... .I3 0.28
Engine coolant temperature (ECT) sensor.
testing and replacing
................. .I3 0.30
Intake air temperature (IAT) sensor.
testing and replacing
................. .I3 0.31
MS 42.0 throttle valve assembly. replacing . 130-32
MS 43.0 throttle valve assembly. replacing . 130-35
Throttle cable. adjusting (MS 42.0) ...... .I3 0.38
ldle speed control valve. checking
and replacing
....................... .I3 0.38
Evaporative emissions control diagrams . . 130- 39
Evaporative emissions control.
(MS
42.0 and MS 43.0). .............. .I3 0.39
Engine control module (ECM).
removing and installing
................ 130-40
Siemens MS 42.0 and MS 43.0
ECM pin assignments ................. 130-41
Bosch M5.2 (M62 up to 911997)
BOSC~ M5.2.1 (M62 911997 to 911998) 130-46
M5.2 system features ................. 130-47
M5.2.1 system features ............... 130-47
ECM relay. testing ................... 130-49
Oxygen sensors. checking ............. 130-51
Fuel injectors. checking and replacing .... 130-52
Mass air flow (MAF) sensor. replacing .... 130-53
ldle speed control valve. testing
and replacing
....................... 130-54
Throttle position sensor (TPS).
testing and replacing
................. 130-55
Engine coolant temperature (ECT) sensor.
testing and replacing
................. 130-55
Intake air temperature (IAT) sensor.
testing and replacing
................. 130-57
Auxiliary throttle valve (ADS) (M62 and
M62 TU engine). replacing ..... 130-57
Evaporative system pressure
leak diagnosis. overview
(5.2.1 only) ..... 130-58
Bosch 5.2 ECM pin assignments
(M62 UP to 911 997) ................... 130-59
~osch 5.2.1 ECM pin assignments
(M62 911 997 to 911 998) ............... 130-62
BOSC~ ME 7.2 ..................... 1 30-66
ME 7.2 system overview ............... 130-67
EDK adaptation ..................... 130-69
ECM relay. checking .................. 130-69
Engine coolant temperature
(ECT) sensor. testing
................. 130-71
Engine coolant temperature
(ECT) sensor. replacing
............... 130-71
Oxygen sensors. replacing ............. 130-72
Fuel injectors. removing and installing .... 130-72
Mass air flow (MAF) sensor.
removing and installing
................ 130-73
Evaporative system pressure
leak diagnosis. overview
............... 130-74
Secondary air injection. overview ........ 130-75
Bosch ME 7.2 ECM pin assignments .... 130-76

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130-1 3
Fuel Injection I
< Unplug harness connector (arrow) from sensor.
CAUTION-
Be sure ignition is OFF before disconnecting or reconnecting
DME system components.
NOTE-
Do not confuse the throttle position sensor on the main Nirot-
tle body with the throttle position switch on the secondary
throttle body, where applicable.
- Remove two mounting screws holding sensor to throttle
housing.
- Installation is reverse of removal. Clear adaptation settings
from ECM using BMW-compatible scan tool.
NOTE-
Poor idle quality may be noticeable for a period if the adapta-
tion settings are not cleared after installing new TPS.
ldle speed control valve,
checking and replacing
The idle speed control valve regulates idle speed by redirect-
inq airaround the throttlevalve.The idlespeed control valve is
mounted on the underside of the intake manifold adjacent to
the dipstick tube bracket. Accessing the valve is best accom-
plished by first removing the air filter housing and the throttle
body assembly.
The valve issupplied with
batteryvoltagefrom the ECM relay.
The idle speed control valve incorporates a two-coil rotary ac-
tuator. The ground sides of each coil are pulsed
sirnulta-
neously by the ECM. The duty cycle of each circuit is varied to
achieve the required idle speed.
Afaulty ldle speed control valve sets afault code and the MIL
is illuminated when
OED II fault criteria are exceeded.
Before checking the idle speed control valve, confirm that the
throttle position sensor is working correctly.
- With engine running, check that idle speed control valve is
buzzing.
- Turn on AIC system or shift transmission into drive. ldle
should remain steady or increase slightly.

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Fuel Injection 1
NOTE-
The 1998 5281' with MS 41.1 requires a barometric pressure
sensor input signal for activation of the
LDP check. This sen-
sor is located on the passenger side strut tower
fo~lard of
ABS/ASC hydraulic unit.
Evaporative emissions
1. ECM
2. Purge valve
3. Leak detection pump (LDP) (in
lefl rear wheel housing)
4. Filter
5. Liquid vapor separator
6. Purge canister
7. Fuel tank
Secondary air injection, overview
The secondary air system pumps ambient air into the exhaust
stream afler a cold engine start to reduce the warm up time of
the catalytic converters and to reduces HC and CO emis-
sions. The ECM controls and monitors the secondary air in-
jection system. The secondary air pump operates at a start
temperature of between 10°C (50°F) and 40°C (104°F) and
continues to operate for a maximum of
2 minutes at idle
speed.
The electric air pump draws in ambient air and supplies it to
the divertervalve. The vacuum ventvalve (solenoid) switches
vacuum to open the divertervalve when activated by the
ECM. Once opened, the diverter valve allows air to be
pumped into the exhaust stream.