knock sensors BMW 540i 2000 E39 Workshop Manual

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- .-
.. Cylinder Head Removal and Installation I -
< Disconnect the following electrical harness connectors:
Knock sensors
(A).
Thermostat (6).
Throttle position sensor and idle valve (C).
Camshaft position sensor (D).
Ignition coils (E).
< Remove mounting nuts (arrows) from wiring harness ducts.
4 Release fuel injector connectors by releasing spring clip
(arrow) on each injector.
Lift up and remove electrical ducts and set to one side

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120 lgnition System
...................... General
Special tools ...................
Warnings and cautions ...........
Engine management .............
................. lgnition system
Ignition system. troubleshooting
....
... Oscilloscope diagnostic diagrams
................ Misfire detection
............. Ignition System Service 120-9
.................... Ignition firing order 120-9
.............. Disabling ignition system 120-10
................... Checking for spark 120-1 0
lgnition coil assembly.
................. testing and replacing 120-1 0
.............. Crankshaftspeedsensor 120-12
............. Camshaft position sensors 120-1 4
...................... Knocksensors 120-16

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Lnition switch
4 The positive (+) power supply to the ignition coils comes to
the ignition switch via an unloader relay. When the ignition
switch is turned on, the relay closes, to provide voltage to the
ignition coils. The coils are then actuated at the negative side
by the engine control module.
NOTE-
Schematic diagrams shown are for illustrative purposes only.
See ELE Electrical Wiring Diagrams for engine manage-
ment specific wiring information.
WARNING- Do not touch or disconnect any cables from the coils while
the engine is running or being cranked by the starter:
The ignition system produces high voltages that can be
fatal. Avoid contact with exposed terminals. Use ex-
treme caution when
working on a car with the ignition
switched on or the engine running.
* Connect and disconnect the DME system wiring and
test equipment leads only when the ignition is
OFF
Before operating the starter without starting the engine
(for example when
making a compression test), always
disable the ignition.
4 Knock sensors (arrows) monitor the combustion chamber for
engine-damaging knock. Six-cylinder models (shown) use
two sensors with each sensor monitoring three cylinders.
V-
8 models use four sensors, each monitoring two cylinders. If
engine
knock is detected, the ignition point is retarded by the
ECM.
I Ignition advance Ignition timing is electronically mapped and not adjustable.
The ECM uses engine load, engine speed, coolant tempera-
ture, knock detection, and intake air temperature as the basic
inputs for timing control.
A three dimensional map similar to
the one shown is digitally stored in the ECM.
- The initial ignition point is determined by the crankshaft
speed sensor during cranking. Once the engine is running.
timing is continually adjusted based on operating conditions.

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I Ignition System
Camshaft position sensors
The camshaft position sensors are used by the englne man-
agement system for VANOS control, sequential fuel injection
and knock control.
Intake camshaft position sensor, replacing
(M52,M52 TU
and M54 engines)
- Make certain ignition has been turned off.
- Remove plastic cover from above fuel injectors by prying off
bolt covers and removing cover mounting bolts.
Remove complete air filter housing:
Disconnect electrical harness connector on mass air flow
sensor
(A).
Detach vacuum line at intake boot (B).
Loosen hose clamp at intake boot and detach air duct con-
nections
(C).
* Disconnect cold air duct tube (D).
Remove filter housing mounting screws (E).
- Disconnect harness connector from VANOS solenoid and
unscrew solenoid from VANOS control unit. Be prepared with
shop rags to catch oil released from VANOS unit.
Remove camshaft sensor (arrow) from
left front of cyl~nder
head, next to top of oil filter housing.
Disconnect camshaft sensor harness from under intake
manifold. Prior to removal, attach a stiff piece of wire to the
harness connector end to preserve proper routing of harness
for reinstallation.
Installation is reverse of removal, noting the following:
Use new O-rings when installing sensor and solenoid.
Be sure wiring is rerouted in same orientation.
Use scan tool to read out and clear
ECM fault memory
Tightening torques
-
Intake camshaft sensor to cylinder head 10 Nrn (7 ft-lb)
VANOS solenoid to VANOS control unit 30 Nm (22 ft-lb)

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120-1 6
Ignition System
Remove camshaft sensor (arrow) from front of right cylinder
head.
Disconnect camshaft sensor harness from cable duct above
right cylinder head.
Installation is reverse of removal, noting the following:
Use new O-ring when installing sensor.
Be sure wiring is rerouted in same orientation.
Use scan tool to read out and clear ECM fault memory.
Tightening torque Intake camshaft sensor to timing chain 5 Nm
(3.5 ft-lb)
cover
Knock sensors
Knock sensors, replacing (M52, M52 TU and M54
engines)
The knock sensors are bolted to the left side of the cylinder
block under the intake manifold.
- Remove intalte manifold as described in 113 Cylinder Head
Removal and Installation.
D~sconnect knock sensor electrical harness connector (A) on
left side of engine cylinder block.
Remove knock sensor
mount~ng bolts (arrows) on side of
cyllnder block. Remove sensors.
Note the installed angle of the
lnocl~ sensor on the bloc/( be-
fore removing it. Reinstall the sensor
in the same position. Be
sure to use a torque wrench when tightening the sensor
mounting bolt.
< Clean lknock sensor contact surface on engine bloclc and
sensor (arrows) before installing
ltnock sensor.
Tightening torque
Knock sensor to head 20 Nm (15 ft-lb)
- Use scan tool to read out and clear ECM fault memory.
Knock sensors, replacing
(M62 and M62 TU engines)
The
knock sensors are bolted to the side of the cylinder block
under the
intake manifold.

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Ignition System
Remove intake manifold as described in 113 Cylinder Head
Remaval and Installation.
Remove knock sensor mounting bolts (arrows) on side of
cylinder block. Remove sensors.
I CAUTION- I
Note the installedangle of the knock sensors on the bloclt be-
fore removalit. Reinstall the sensors in the same position. Be
sure to use
a torque wrench when tightening the sensor
mounting bolts.
Clean
lknoclc sensor contact surfaces on engine bloclc and
sensors before installing.
Tightening torque
Knock sensor to engine
bloclc 20 Nm (15 ft-lb)
- Use scan tool to read out and clear ECM fault memory.
- Installation is reverse of removal.

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Fuel Injection
- Ignition:
Direct ignition
Knock control
4 Primary1 secondary ignition monitoring
- Emissions:
OBD II compliance
Secondary air injection
Pre- and post-catalyst oxygen sensors
0 Electrically heated DME-mapped thermostat
Misfire detection
Evaporative emission control and
leak detection
Malfunction indicator light (MIL)
Performance controls:
Dual VANOS control
Output of injection signal (TI) for fuel economy gauge
Output of engine rpm (TD) for tachometer
AIC compressor control
0 Electric radiator cooling fan
CAN-Bus communication
Stability and traction system
(ABSIASCIDSC) interlace
Electronic immobilizer (EWS)
Cruise control
ECM programming

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Fuel Injection
M5.2 system features
The Bosch M5.2 system used on 1997 540i models uses an
88-pin control unit. The
M5.2 system has the following func-
tions and capabilities:
Fully sequential cylinder-individual fuel injection.
Integrated adaptive knock control.
Oxygen sensor fuel mixture control.
0 Self-diagnosis and emergency operation characteristics.
CAN-Bus link.
0 OED II functions (misfire detection, catalytic converter
monitoring, oxygen sensor monitor, and fuel tank ventila-
tion system).
Electronic vehicle immobilization via EWS.
One-touch starter function.
Control of characteristic map thermostat.
M5.2.1 system features
The Bosch M5.2.1 system is used on 1998 540i models. The
M5.2.1 control module utilizes the SKE (standard shell con-
struction housing) with 5 connectors and a combined total of
134 pins.
The M5.2.1 systefn has
tile following functions or capabilities:
Separate power supply relay for ignition coils. Leak diagnosis pump (LDP) control and feedback
rnonitor-
ing for evaporative system leak testing.
Fuel evaporative system providing ORVR (on-board refuel-
ing vapor recovery) compliancy.
Batterylalternator charge logic (idle speed varied with the
battery state of charge).
CAN-Bus communications with the instrument cluster
EWS
Ill "rolling code" ISN interface.
More sensitive ignition
knock sensors.
Pulse width modulated (P-W-M) Heating and
AIC (IHKA)
status signal.
Running loss (312-way) solenoid valve.

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130-60
/Fuel lniection
Tabled. Bosch M5.2 ECM pin assignments
Note
Pin
21
20 I output / Crankshaft position sensor (speed and position) I Crankshaft positionlrpm sensor
23
I - I I 29 1 output I Idle speed control - opening winding I Idle speed control valve (cycled ground)
Type
22
1 output I Cvl. 6 ignition signal (primary signal) I Cyl. 6 ignition coil (RZV adapter)
output
25
26
27
28
Component/function
24 1 outout I Cvl. 7 iqnition siqnal (primary signal) I Cyl. 7 ignition coil (RZV adapter)
output
4 outbut I' I - I Cyl. 3
fuel injection valve I Cyl. 3 fuel injection valve (cycled ground)
Camshaft position
sensor (cylinder reference)
output input
output
oround
30
31
32
ground Hall effect camshaft position sensor
Cyl. 3 ignition signal (primary signal)
output
I
Cyl. 3 ignition coil (RZV adapter)
. - . .. . .
Cyl. 2 ignition signal (primary signal)
Terminal 30
Engine control module relay
Ground for electronics and sensor shield
output
output
outout
Remaining output stages ground
(not iclnition and fuel iniection valves) Cyl.
2 ignition coil (RZV adapter)
Fuse carrier, engine electronics
Engine control module relay
Ground splice ,
Cyl. 2 fuel injection valve
Oxygen sensor heater signal
Cyl. 5
fuel injection valve
Cvl. 8 fuel iniection valve
AIC comuressor relav sianal
Heated oxygen sensor I in front of catalytic converter,
Heated oxygen sensor
iI in front of catalytic converter
Cyl.
5 fuel injection valve (cycled ground)
Cvl. 8 fuel iniection valve (cycled ground)
. -
Not used Ground point
Cyl.
2 fuel injection valve (cycled ground)
Heatinq and AIC control module (ground - compressor OFF)
38 Not used
40 39
1 I Not used
I'
I . I
I' I -. I
46 1 ground I Heated oxygen sensor signal (voltage 0.1-1.0 V) I Oxygen sensors
41
1 inuut I Knock
sensor signal I Knock sensor
input
I
I I
Instrument cluster
I' I I 55 1 ground I Ignition ground I Ground point
Knock sensor signal
43
1 I Not used I
Fuel reserve signal
42
Throttle position sensor
47
48
49
50
51
52
53
54
Knoclc sensor
input
45
1 outout I Hot film mass air flow sensor signal (0-5 V) I Hot film mass air flow sensor
Throttle position sensor signal
(0.4-4.2 V) 44
input
output
output
output
output
output
inout
I - I
Not used
Not used
Cyl. 1 ignition signal (primary signal)
Cyl. 5 ignition signal (primary signal)
Cyl. 4 ignition signal (primary signal)
Cyl. 8 ignition signal (primary signal)
Throttle position sensor
(c 5 V voltage supply)
Terminal 87
f> 10 V)
ignition switch
56
Cyl. 1 ignition coil (RZV adapter)
Cyi. 5 ignition coil (RZV adapter)
Cyi.
4ignition coil (RZV adapter)
Cyl. 8 ignition coil (RZV adapter)
Throttle position sensor
Fuse
F1
input Terminal 15 (> 10 V)

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130-67
Fuel Injection /
ME 7.2 system overview
The Bosch ME 7.2 system is used on 1999 - 2002 540i mod-
els.
1 4 The ME 7.2 enaine control module (ECM). located on the
l and a combined total of 134 pins.
--__-- 1 I. 9 pin connector
12 3 4 5 2 24 pin connector
0lliC;nii, 3. 52 pin connector
4. 40 pin connector
5. 9 pin connector
The ME 7.2 system has the following functions or capabilities:
Electronic throttle control (EDK) integrates idle and cruise
control functions. ECM carries out all throttle and idle con-
trol functions directly via EDK system.
Leak diagnosis pump
(LDP) control and feedback monitor-
ing for evaporative system leak testing.
Batterylalternator charge logic (idle speed varies with bat-
tery state of charge).
CAN-Bus communications with instrument cluster.
EWS
111 (3.3) "rolling code" ISN interface.
Ignition
knock sensors.
DSC (dynamic stability control) torque reduction.
Monitoring and control of VANOS
(camshaft timing) with
active Hail sensor for camshaft position monitoring.
Integrated altitude sensor.
One touch engine start control
Single speed secondary air injection system.
Long life spark plugs.
IHKA auxiliary (electric) cooling fan control.
All emissions-related ME 7.2 electrical components are mon-
itored for faults. if driveability complaints are encountered or
the malfunction indicator
light (MIL) is illuminated, interrogate
fault memory using a compatible scan tool.
4 Use a break-out box for ME 7.2 system testing and diagnosis
at the control module
(break out box set: BMW special tool
90
88 6 121 300).
Electrically heated (characteristic
map) cooling system
DME Harness Connector thermostat.