1999 BMW 540i dme

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Fuel Injection
Engine coolant temperature
(ECT) sensor,
testing and replacing
4 The ECT sensor is located below cylinder 6 intake port at the
rear of the engine (1).
The ECT sensor is a dual temperature sensor. One circuit
provides coolant temperature information to the ECM while
the other circuit provides coolant temperature information to
the instrument cluster.
The ECM determines the correct ignition timing and airlfuel
mixture required
forthe engine temperature by monitoring an
appliedvoltage
(5vdc) to the sensor.Thevoltage drop across
the sensor varies as the coolant temperature (sensor resis-
tance) changes.
NOTE-
The ECT sensor is an NTC (negative temperature coeffi-
cient) type sensor. In other words, as the temperature rises,
resistance through the sensor decreases.
If the ETC sensor input is faulty or non-plausible, the MIL is il-
luminated when the MIL is illuminated when
OED II fault crite-
ria are exceeded. The ECM assumes a substitute value
(80" C 11 76'F) to maintain engine operation. The ignition tim-
ing is set to a
conservativelsafe basic setting.
- Remove intake manifold to access ECT sensor on the M52
TU and the M54 engines. See 113 Cylinder Head Removal
and Installation.
- Check ECT sensor resistance using a multimeter at sensor
terminals.
WARNING -
Due to rislc of personal injury, be sure the engine is cold be-
fore removing ECT sensor connector.
ECT sensor resistance @ 20°C (68°F)
CAUTIOI\C
Be sure ignition is OFFbefore disconnecting or reconnecting
DME svstem components.
2.2 - 2.7 k
4 Disconnect ECT sensor harness connector (arrow). Un-
screw ECT sensor from cylinder head.

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. .
Fuel Injection
Check resistance of valve across valve terminals
Idle speed control valve coil resistance
Terminals
1 and 2 20 i2.0.
Terminals 2 and 3 20 i2.0.
Terminals 1 and 3 40 i4.0.
CAUTIOIG
Be sure ignition is OFFbefore disconnecting or reconnecting
DME system components.
- To remove valve, remove cable bracket mounting bolt and
idle speed control valve mounting bracket bolts from front of
throttle housing and remove idle speed control valve with at-
tached bracket.
NOTE-
When installing idle speed control valve, remove intake boot
sealing ring from valve and install into intake air boot. Then
install valve info sealing
ring.
Evaporative emissions control diagrams
MS 42.0 (LDP) ,-a"-
Evaporative emissions control,
(MS 42.0, MS 43.0)
E39 models with MS 42.0 or MS 43.0 engine are equipped
with a fuel system evaporative pressure leak diagnosis sys-
tem. The main component of this system is the leak diagnosis
pump (LDP or DM-TL). The function of either system is to
pressurize the fuel tank and the evaporative emission system
for the purpose of detecting leaks.

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. -
Fuel Injection I
Working inside E-box, disconnect ECM harness connector
(arrow) by releasing fastener and pivoting connector up and
off ECM.
CA UTIOW
Be sure ignition is OFF before disconnecting or reconnecting
DME system components.
Remove ECM from retaining brackets and lift off holder.
Installation is reverse of removal
Before attempting to start engine, use
BMW service tester
DISplus, MoDiC, GTl or equivalent:
* Code replacement ECM with application information (i.e
engine code, transmission type, etc.).
Align ECM to EWS (electronic immobilizer).
Siemens MS 42.0 and MS 43.0
ECM pin assignments
ECM pin assignments are given in Table c. For engine man-
agement system schematics, see
ELE Electrical Wiring Di-
agrams.
/ CAUTIOW I
Al~ays wait at least one mfnule after turning off the ignition
before
remov;ng [he connecror irom rhe ECM. If the con-
nector is removed before this time, residual power
in the
system relay may damage the
ECM.
Always connect or disconnect the control module con-
nector and meter probes with the ignition off.
When making checks at the ECM itself, a
breakout box
should be used to allow tests to be made with the connector
attached to the ECM. This also prevents damage to the small
terminals in the connector. As an alternative, the harness
connector housing can be separated so that electrical checks
can be made from the back of the connector.
Table
c. Siemens MS 42.0 and MS 43.0 ECM pin assignments
Pin
lslgnal l~om~onentlfunction 1 Notes
Connector
X60001 9-pin black
1 loutput I~erminai 15 I Unloeder relay terminal 15
2 I 1 Not used I
3 Not used
4 Ground
Ground Ground
point

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.-
/Fuel Injection
I ' I - I
9 /ln~ut l~oltaqe supply I Fuse carrier, engine electronics
Table
c. Siemens MS 42.0 and MS 43.0 ECM pin assignments (continued) I ' I . I
Connector X60002 24-pin
1 linput IHeater, precatalyst oxygen sensor 1 I Heated oxygen sensor 1 in front of cat. conv.
I I I
18 llnout IHeater, post-catalyst oxygen sensor 2 ]Heated oxygen sensor 2 behind cat. conv.
Notes
Ground connector
Ground connector
B+ terminal
Fuse carrier, engine electronics
Pin
5
6
7
8
I I I
4 loutput l~hrottle valve supply (MS
42.0) I~hrottle valve (MS 42)
Signal
Ground
Ground Input
lnout
19
20 21
22
23
24
Connector
1
2
3
I I I
5 1 lnput ISignal, intake camshaft position sensor /camshaft position sensor 1
Componentlfunction
Ground
Ground
Terminal 30
Voltaae
SUDP~V
input
Ground
Ground
Ground
Input
Ground
X60003 52-pin
Input
Input
~ -
Heater, post-catalyst oxygen sensor 2
Ground, precatalyst oxygen sensor
1
Ground, precatalyst oxygen sensor 2
Ground, post catalyst oxygen sensor
1
ECM (DME main) relay signal activation
Ground, post catalyst oxygen sensor 2
Signal, mass air
flow sensor
Signal, exhaust camshaft sensor
Not used Heated
oxygen sensor 2 behind cat.
conv.
Heated oxygen sensor 1 in front of cat. conv.
Heated oxygen sensor 2 in front of cat. conv.
Heated oxygen sensor
1 behind cat. conv.
ECM
Heated oxygen sensor 2 behind cat. conv.
Hot film mass air flow sensor
Camshaft position sensor

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- Fuel Injection
ECM relay, testing
The engine control module (ECM) relay is energized via the
ECM and supplies battery positive
(B+) power to many of the
engine
management components and subsystems. If this re-
lay is faulty, the engine will not start.
CAUTIOI\C
Relay positions can vary. Be sure to confirm relay position by
identifying the wiring
in the socket using the wiring diagrams
in ELE Electrical Wiring Diagrams.
NOTE-
The ECM relay is also referred to as the DME main relay.
ECM relay powers:
* ECM
Ignition coils
Fuel injection
Evaporative leak detection pump
(5.2.1 only)
Idle air actuator
Camshaft sensors Evaporative emissions valve
Hot film mass air flow sensor
Fuel pump relay
Oxygen sensor heaters
4 Working in right rear of engine compartment:
Release interior ventilation filter cover latch
(A) and re-
move cover.
Release plastic locking tab
(B).
Rotate duct inward (arrow) to unloclc from bulk head and
remove duct.
0 Release spring lock (C) to remove lower filter housing.
Slide filter housing away from inner fender to remove.
- Remove electrical box (E-box) cover fasteners and remove
cover.

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130-51
Fuel Injection
Oxygen sensors, checking
The oxygen sensor provides an input voltage signal [0.2 vdc
(lean) to 0.8 vdc (rich)] to the
ECM based on the oxygen con-
tent in the exhaust gas. To generate voltage, the sensor tem-
perature must exceed 575"
F (300" C). Therefore the sensor
is electrically heated.
NO JE -
The test given below is not a conclusive test of oxygen sen-
sor efficiency and does not test how the oxygen sensor re-
acts to changing conditions. Pin numbers and wire colors
can vary Always check the wiring diagrams to confirm wire
color and pin assignment.
0 The oxygen sensorconnectorplugs are locatednext to the
catalytic converters.
With connector attached to sensor, connect digital voltmeter
between
A and B wires in connector.
WARNING -
Exhaust manifolds andpipes can be hot enough to cause se-
rious burns. Wear suitable heavy gloves and other appropri-
ate protection.
NOJE-
Connector style may vary depending on system application.
Consult wiring diagram for system-specific wiring. See
ELE
Electrical Wiring Diagrams.
Start engine.
A fluctuating voltage signal should show on the
meter.
If voltage is incorrect, turn engine off and check pre-
heater circuit as described below.
NOJE-
To check sensor response to lean and rich mixtures, create
an air leak.
Oxygen sensor
voltage at idle
- Connect digital voltmeterbetween sensor heaterwires (white
wires,
C and D). Start engine and check for battery voltage.
If voltage is not present, check oxygen sensor heater fuses.
0.2 to 0.8 vdc fluctuating
NOJE-
The oxygen sensor heater is powered via fusedpositive (+)
battery voltage and a switchedground from the ECM. See
ELE Electrical Wiring Diagrams for specific circuit informa-
tion.
- The ground side of the oxygen sensor heater circuit is pulsed
on and off by the
DME control module.

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130-54
I Fuel Injection ldle speed control valve,
testing and replacing
ldle speed is maintained by the ECM through the idle speed
control valve. The idle control function compensates for en-
gine load and engine operating conditions. ldle speed is
adaptive through the ECM and no adjustments can be made.
Before checking valve, confirm that throttle position sensor is
working correctly.
NOTE-
The test given below is an electrical check only. It does not
check the mechanical operation of the valve. If the valve is
sticking, hanging up or is sluggish in operation, substituting a
Inown good valve is the best way to check it.
With engine running, check that idle speed control valve is
buzzing.
Turn on
AIC or shift car into drive. ldle should remain steady
or increase slightly.
If valve is not buzzing, or if idle decreases in step above, stop
engine and disconnect harness connector from valve.
4 Check resistance of valve across its terminals. Test values
are listed below.
ldle speed control valve coil resistance
Terminals
1 and 2 20 +2%
Terminals 2 and 3 20 +2Q
Terminals 1 and 3 40 +4%
NOTE-
If you suspect an intermittent fault, lightly tap the valve while
testing resistance.
With valve harness connector disconnected, check for bat-
tery voltage at redlwhite wire in connector with ignition on.
If . ~~ ~~
there is no voltage, check wiring between connector and 7 ECM relay. See ELE Electrical Wiring Diagrams.
NOTE- - The idle speed control valve receivespositive (+) battery volt-
age from the ECM (DME main) relay

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Fuel Injection
Intake air temperature
([AT) sensor,
testing and replacing
Disconnect harness connector from intake air temperature
sensor
(A) at air filter housing.
Turn ignition on. Using a digital voltmeter, check for
5 volts
between supply voltage wire in connector and ground.
If volt-
age is not present, test ECM
inputs/outputs as described lat-
er.
With harness connector disconnected, test resistance across
sensor terminals. If any faults are found, replace IAT sensor.
IAT test resistance
0 lV *lac (50" i-2°F) 7-1 1.6 k.0.
020' kl°C (68' 322°F) 2.1-2.9 it.0.
080" ?lac (176" i-2°F) 0.27-0.40 itn
Auxiliary throttle valve (ADS)
(M62 and M62 TU engine), replacing
ADS components 540i models with ASC and DSC are fitted with a motor-driv-
en auxiliary throttle valve and housing ahead of the standard Throttle position switch throttle housing. The ADS throttle valve controls engine throt-
tle intervention based on signals from the DME control mod-
ule if road conditions, such as slipping driven wheel, warrant
reduced engine power.
ADS throttle housing
Bowden cable NOTE-
Before replacing the ADS throttle housing, read DME fault
ADS lhroltle actualor codes.
- ADS throttle housing replacement:
Switch off ignition and disconnect electrical connector on
ADS throttle body.
Remove hose from idle control valve.
Loosen hose clamps and remove throttle housing air in-
take boot.
Disconnect cable from ADS throttle body.
- Unscrew 3 bolts and remove ADS throttle body.
Installation is reverse of removal.
- Adjust cable so that no free play is present.