2001 BMW 540i Timing

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I Fuel lniection
varies as the coolant temperature (sensor resistance) chang-
es.
NOTE-
The ECT sensor is an NTC (negative temperature coeff-
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 MILis il-
luminated when OBD
II fault criteria are exceeded. The ECM
assumes a substitute value
(8OoC/176"F) to maintain engine
operation. The ignition timing is set to a
conservativelsafe ba-
sic setting.
4 Disconnect ECT sensor harness (A)
- Checlc ECT sensor resistance using a multimeter at sensor
terminals
3 and 4. Peel back protective boot (B) to ID termi-
nal numbers on connector housing.
/ ECT sensor resistance @l 2O" C (68°F) 2.2 - 2.7 kd
WARNING -
Due to risk of personal injug be sure the engine is cold be-
fore disconnecting ECT harness connector.
Sensor replacement: Disconnect ECT sensor harness (A).
- Unscrew ECT sensor from cylinder head and install new sen-
sor.
Use new copper sealing washers
when installing sensor.
Replace any lost coolant.
Tightening torque
ECT sensor to coolant flange 13 Nm (I0 it-lb)

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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.

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Fuel Injection I
Engine coolant temperature (ECT) sensor,
testing
The ECT sensor is located on the front of the engine in the
coolant~thermostat flange. The ECT sensor is a dual temper-
ature sensor. One circuit provides coolant temperature infor-
mation 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 for the engine by monitoring an applied volt-
age
(5 vdc) to the sensor. Thevoltage drop across the sensor
varies as the coolant temperature (sensor resistance) chang-
es.
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 OBD
II fault criteria are exceeded. The ECM
assumes a substitute value
(80" C/ 176°F) to maintain engine
operation. The ignition timing is set to a
conse~ativelsafe ba-
sic setting.
Disconnect harness from
ECTsensor (A) at coolant flange at
front of engine.
- Check ECT sensor resistance using a multimeter at sensor
terminals
3 and 4. Peel back protective boot (B) to ID termi-
nal numbers on connector housing.
I ECT sensor resistance @ 20" C (68°F) I 2.2 - 2.7 lkCi
Engine coolant temperature (ECT) sensor,
replacing
I WARNING-
/ Due to risk ofpersonal injury, be sure the engine is cold be- I
I fore replacin~~~~sensor. -
-
I
- Disconnect ECT sensor harness.
- Unscrew ECT sensor from cylinder head and install new sen-
sor.
Use new copper sealing washers when installing sensor.
Replace any lost coolant.
Tightening torque
ECT sensor to coolant flange 13 Nm (10 it-lb)

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170-1 9
Radiator and Cooling System
Coolant pump Remove thermostat housing fasteners
(arrows) and remove
thermostat housing.
Installation is reverse of removal, noting the following:
- Keep sealing faces clean and free of oil.
Use new sealing gasket.
Fill system with coolant. See Coolant, draining and fill-
ing
(V-8 models).
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
- 3 Nm (18 - 27 In-lb)
Thermostat cover to
coolant pump 10 Nm (89 in-lb)
Coolant pump, replacing (6-cylinder
models)
< The engine coolant pump is mounted in the front of the en-
gine in the timing chain cover.
- Drain cooling system as described earlier. See Coolant,
draining and filling (6-cylinder models).
WARNING-
Allow cooling system to cool before opening or draining sys-
tem.
- Remove cooling fan and fan shroud. See Mechanical (vis-
cous clutch) cooling fan, removing and installing.
- Remove coolant pump drive belt. See 020 Maintenance.
4 Remove coolant pump pulley bolts (arrows) and remove pul-
ley from pump.
- Remove nuts retaining pump to engine block.
NOTE-
The coolant pump is mounted on studs and retained by nuts.

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.," --
Radiator and Cooling System --- 1
insert two M6 screws (arrows) in tapped bores and tighten
uniformly until pump is free from timing chain cover (thermo-
stat and hoses have been removed for purposes of visual
clarity).
Installation is reverse of removal, noting the following:
Be sure to replace sealing O-ring and gaskets.
Coat O-ring with water-based lubricant during installation.
Refill with coolant. See Coolant, draining and filling
(6-
cylinder models).
Tightening torques
-
Coolant pump to timing chain 10 Nm (89 in-lb)
cover
Coolant pump pulley to coolant
10 Nm (89 in-lb
pump
Engine block drain plug to block 25 Nm (1 8 It-lb)
Radiator drain plug to radiator 2 - 3 Nm (I8 - 27 in-lb)
Coolant pump, replacing (V-8 models)
I 1 < The engine coolant pump is mounted in the front of the en-
gine in ;he timing chain cover.
1. Thermostat housing
2. Thermostat
3. Thermostat sealing O-ring
4. Water pump
5. Water pump gasket
- Drain cooling system. See Coolant, draining and filling (V-
8 models).
- Remove cooling fan and fan shroud. See Mechanical (vis-
cous clutch) cooling fan, removing and installing.
- Remove engine drive belts: See 020 Maintenance.
NOTE-
Mark direction of drive belt rotation if reusing belt,
- Remove vibration dampener. See 117 Camshaft and Tim-
ing Chain.
- Disconnect mass air flow (MAF) sensor electrical harness
connector. Remove air intake duct together with
MAF sensor.
- Disconnect coolant hoses from thermostat housing and cool-
ant pump housing.

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.. - --
Radiator and Cooling System
Tightening torques
Coolant pump to timing chain 10
Nm (89 in-lb)
cover
Coolant pump
pulley to coolant
pump
10 Nm (89 in-lb
Engine
blocic drain plug to block 25 Nm (18 ft-lb)
Radiator drain plug to radiator
2-3Nm(18-27in-lb)
Thermostat cover to coolant
pump assembly 10 Nm (89 in-lb)
Radiator, removing and installing
Removal of the radiator is similar for V-8 and 6-cylinder mod-
els.
- Raise front of car and support safely.
WARNING -
Make sure the car is stable and well supported at aN times.
Use a professional automotive liff
orjaclc stands designed for
- Remove splash shield from under engine.
- Drain radiator and engine block. See Coolant, draining and
filling
(V-8 models).
WARNING -
Allow cooling system to cool before opening or draining sys-
tem.
< Remove air filter housing:
Disconnect electrical harness connectors
(A and B).
Loosen clamps (C and D).
Remove mounting fastener (arrow) and remove air filter
housing together with mass air flow
(MAF) sensor.

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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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On-Board ~iaanosticsl
Engine diagnostic trouble codes: M54 engine
P-code
BMW-FC Explanation
PO01 I / 103 I 'A' Camshaft Position Timing Over-Advanced or System Performance (Banlc 1) I I
PO012 1105 I 'A' Camshaft Position Timing Over-Retarded (Bank 1) I I
PO01 4 1104 I 'B' Camshaft Position Timing Over-Advanced or System Performance (Bank 1)
PO01 5
PO030
PO031
PO032
I 1
PO038 179 / HO2S Heater Control Circuit High (Bank 1 Sensor 2)
I I -.
I I
PO050 1 55 I H02S Heater Control Circuit (Bank 2 Sensor 1)
106
25
25
25
PO036
I I
PO051 1 55 I H02S Heater Control Circuit Low (Bank 2 Sensor 1)
'B' Camshaft Position Timing Over-Retarded (Bank 1)
H02S Heater Control Circuit (Bank 1 Sensor 1)
H02S Heater Control Circuit Low (Bank 1 Sensor 1)
H02S Heater Control Circuit Hiqh (Bank 1 Sensor 1)
PO037 1 79 I HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
79
HOPS Heater
Control Circuit (Banlc 1 Sensor 2)
PO052
PO056
PO057
PO058
I I
PO1 03 / 8 I Mass or Volume Air Flow Circuit High. Input
I I -.
I I
PO1 07 1 197 I Manifold Absolute PressureIBarometric Pressure Circuit Low Input
55
61
61
61
PO101
I I
POI08 1197 / Manifold Absolute PressureIBarometric Pressure Circuit High Input
H02S Heater Control Circuit High (Bank 2 Sensor 1)
H02S Heater Control Circuit (Bank 2 Sensor 2)
HO2S Heater Control Circuit Low (Bank 2 Sensor 2)
HO2S Heater Control Circuit Hiqh (Banlc 2 Sensor 2)
PO102 18 I Mass or Volume Air Flow Circuit Low Input
149
I I -
PO122 112 ThrottleIPedai Position SensorISwitch 'A' Circuit Low
PO123 1112 I ThrottleIPedal Position SensorISwitch 'A' Circuit High
Mass
or Volume Air Flow Circuit
RangeIPerformance
PO112
PO113
PO1 17
PO118
PO121
14
14
10
10
118
PO128
PO1 31
PO132
PO133
PO133
PO1 34 Intake
Air Temperature Sensor 1 Circuit Low
Intake Air Temperature Sensor 1 Circuit High
Engine Coolant Temperature Circuit Low
Engine Coolant Temperature Circuit High
ThrottleIPedal Position SensorISwitch 'A' Circuit RanqeIPerformance
I I
168
150
150
229
231
150
PO135
Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
02 Sensor Circuit Low Voltage (Bank 1 Sensor 1)
02 Sensor Circuit High Voltage (Bank 1 Sensor 1)
02 Sensor Circuit Slow Response (Bank
1 Sensor 1)
02 Sensor Circuit Slow Response
(Banlc 1 Sensor 1)
02 Sensor Circuit No Activitv Detected
(Banlc 1 Sensor 1)
188 02 Sensor Heater Circuit (Bank 1 Sensor 1)