2001 BMW 525i Air sensor

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Fuel Injection
Table e. Bosch 5.2.1 ECM pin assignments
Pin
I~iqnal 1 Description 1 Note
I I I
46 llnput ICrankshaft position sensor Icrankshaft positionlrpm sensor
38
39
40
41
42
43
44
45 Ground Input
Output
Output
Output
Output
Ground
47
48
49
50
51
Not used
I Not used
52
Shield, knock sensor
Oil level
- thermal
Injection signal
injection signal
Idle speed control - opening winding
Idle speed control - closing winding
Not used
Ground
Ground
-- Ground Input
Ground
Ground Not used Knock sensor
Oil level sensor
Cylinder
4 fuel injector
valve
Cylinder
1 fuel injector valve
Idle speed control valve
Idle speed control valve
Shield, crankshaft sensor
5
6
7
12 Not used
Ground
Intake air temperature sensor
Connector
X60004
8
9 10
11
14 1 1 Not used I
Shield, knock sensor
Shield, sensor
I
Shield, sensor 3
Shield, itnock sensor
Input
- Knoclc sensor
Knock sensor
Knock sensor
Knock sensor
Instrument cluster
Output
2 llnput l~erminal 30 voltage supply /Megrated instrument cluster control module (IKE)
Alt. charge indicator signal, terminal 61 1
Not used
Start signal terminal
50
Not used
15
16
17
18
Output
Ignition switch
Not used
Not used
Activation of relay for fuel pump
Not used
19
Fuel pump relay
Output Not used
I I I 20 loutput ICARB signal /Data link connector
Not
used
Not used
Engine speed signal output (TD)
Not used
Light module
21
Cruise control module (Tempomat)
22 llnput I Right rear wheel speed signal /ABS/ASC or ABSIDSC control module
Oulput
Washer
fluid level,
brake fluid level

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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
The PWG potentiometers provide DC voltage signals as in-
put to the ME 7.2 control module for throttle and idle control
functions. Potentiometer signal
1 is the primary signal, poten-
tiometer 2 is used for a plausibility cross-check.
1. Potentiometer 1 ground
2. Potentiometer
1 power
3. Potentiometer 2 ground
4. Potentiometer 2 power
5. Potentiometer 1 signal to ECM
6. Potentiometer 2 signal to ECM
If errors are detected between potentiometer
1 and 2, the
ECM calculates the engine intake air mass (from
MAFsensor
signal) and only utilizes the potentiometer signal that closely
matches the detected
intake air mass. The ECM control mod-
ule uses the air mass signal for a comparative source to pro-
vide fail-safe operation.
If the ECM cannot calculate a
plausible conclusion from the monitored potentiometerthe
EDK motor is switched off and fuel injection cut-out is activat-
ed (no fail-safe operation possible).
EDK is continuously monitored during all phases of engine
operation. If faults are detected, the EDK motor is switched off
and fuel injection cut off is activated. The engine continues to
run extremely roughly at idle speed.
EDK adaptation
When the EDK throttle assembly is replaced, the adaptation
values of the previous EDK must be cleared from the ME 7.2
ECM using the BMW service testeroran equivalentscan tool.
Once the old adaptation values have been cleared, the new
EDK assembly should be installed and adapted as follows:
0 Switch ignition OFF for 10 seconds.
* Switch ignition ON. Afler approximately 30 seconds, the
EDK is briefly activated indicating that the replacement unit
is now adapted to the ME 7.2 system.
NOTE-
This EDK adaptation procedure is also necessary after re-
placing the
ME 7.2 engine control module. However, the ad-
aptation values do not require clearing since they have not
yet been established.
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.
NOTE-
The ECM relay is also referred to as the DME main relay

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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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( Mass Air Flow Sensor
1" Intake air temp. (NTC)
Sensor qround
Reference voltage . . . -., f fitr mass signal I
Fuel Injection I
Release fuel injector locking clips (arrow).
- Remove fuel injector loom boxes and lay to one side.
- Remove 4 fuel rail mounting fasteners.
4 Disconnect fuel line at quick-disconnect. To disconnect,
press in plastic collar (arrow) and separate fuel line.
WARNING -
Fuel may be expelled underpressure. Do not srnol(e or work
near heaters or
other fire hazards. Keep a fire extinguisher
handy. Before disconnecting fuel hoses, wrap a cloth around
fuel hose
to absorb anv leakinq fuel. Plug all open fuel lines.
- Lifl fuel rail and injectors straight up to remove.
- lnstallation is reverse of removal. Use new injector seals and
clamps during installation.
Mass air flow (MAF) sensor,
removing and installing
4 The MAF sensor is provided with operating power from the
ECM relay. Based on intake air mass, the MAF sensor gen-
erates a varying voltage (approx. 0.5
- 4.5 vdc) as an input
signal
back to the ECM. A separate intalte air temperature
sensor is not used.
- Removing MAF sensor:
Remove upper air filter housing locking clips
Unscrew and remove sensor harness.
Disconnect air temperature sensor harness.
Loosen hose clamp.
Remove upper filter housing with sensor.
- lnstallation is reverse of removal

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130-75
Fuel Injection
Secondary air injection, overview
The secondary air system pumps ambient air into the exhaust
stream afteracoid engine start to reduce the warm-up time of
the catalytic converters and to reduces HC and CO emis-
sions. The ME
7.2 ECM controls and monitors the secondary
air injection system. The secondary air pump operates at a
starttemperature 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
checlc valve. The vacuum vent valve (solenoid) switches
vacuum to open the
checlc valve when activated by the ECM.
Once opened, the checlc
valve allows air to be pumped into
the exhaust stream.
4 The secondary air injection system consists of the following
components:
1. Secondary air pump relay
2. Oxygen sensors
3. Catalytic converters
4. Electric air pump
5. Non-return valve
6. Vacuum vent valve

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Fuel lnjection
I 1- I
4 /output l~em~erature signal. E-box fan I E-box fan
Connector
X60002 (continued)
14
15
16
17
18
19
20
21
22
23
24
5
6
7
8
9
10
11
12
13
14
15
16
Input
Input
Input
Input
Ground
Output Heated
oxygen sensor signal
Heated oxygen sensor signal
Heated oxygen sensor signal
Heated oxygen sensor signal
Not used
Heated oxygen sensor, heater ground
Not used
Not used
Not used
Terminal 85 control
Not used Heated oxygen sensor
II behind catalytic converter
Heated oxygen sensor
I in front of catalytic converter
Heated oxygen sensor
I1 in front of catalytic converter
Heated oxygen sensor
I behind catalytic converter
Heated oxygen sensor I in front of catalytic converter
Engine control module relay
Connector
X60003
Ground
Output Input
Ground
Output
Input
Input
Output
Output
Input
Pin 1
2
3
Not used
Ground for electronic components
Voltage supply for hot
film mass air flow sensor
Signal EDK (electric throttle actuator) Hot film mass air flow sensor, ground
Electric throttle actuator
Not used
Voltage signal, terminal 30h
Alternator
D+ (terminal 61) signal
Injection signal
Injection signal
VANOS valve, signal
Type
Output
Output
Output
Ground connector
X6460
Hot film mass air flow sensor
Electric throttle actuator
Hot film mass air flow sensor
Electric throttle actuator, voltage supply
Starter
Alternator (generator)
Cylinder
7 fuel injection valve
Cylinder 6 fuel injection valve
VANOS valve, cylinder
5-8
Descriptionlfunction
Injection signal
Injection signal
Signal evaporative emission valve Notes
Cylinder 2 fuel injector valve
Cylinder 3 fuel injector valve
Evaporative emission valve

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I Fuel Injection
Connector X60003 (continued) Electric throttle actuator
25
- 27 28
29
30
31
32
33
I I I
36 jlnput I Knoclc sensor 2, signal 1 Knock sensor
I I I
Input
26
Output
Output
input
Output
Input
I ' I . I
43 1 ln~ut I Electric throttle actuator, signal (Electric throttle actuator
Ground, electric throttle actuator
1 Not
used
Hot film mass air flow sensor
34
- 37
38
39
40
41
42
injection signal
Injection
signal
VANOS valve, signal
Not used
Thermostat characteristic map, signal
Crankshaft position sensor, signal
Not used
35 l~round I~nock sensor, shield 1 ~nock sensor
Cylinder
8 fuel injection valve
Cylinder
5 fuel injection valve
VANOS valve, cylinders
1-4
Characteristic map
Crankshaft positionlrpm sensor
input
input
Ground
Input
Output
Output
Innut
Hot film mass air flow sensor, signal
I
44
45 46
47
48
49
50
51
52
Connector )(GO004
Knock sensor 4, signal
Knock sensor, shield
Oil
level (thermal)
Injection, signal
Injection, signal
Electric throttle actuator, signal
Not used
Ground
Crankshaft position sensor, signal
Not used
Knoclc sensor, shield
Knock sensor
1, signal
Knock sensor
3, signal
Knock sensor, shield
Secondary air injection pump valve, signal
'
Ground
Input
Ground
input Input
Ground
Input
I' I ... I . ~
Knock sensor
Knocic sensor
Oil level sensor
Cylinder
4 fuel injection valve
Cylinder
1 fuel injection valve
Electric throttle actuator
Crankshaft sensor shield
Crankshaft
positionlrprn sensor
Knock sensor
Knock sensor
Knock sensor
Knock sensor
Secondary air injection pump valve
Notes
Instrument cluster
Integrated instrument cluster control
Secondary air injection pump
relay
Pin
1
2
3
Electric (auxiliary) cooling fan 4
Type
Output
Output
Outout
Descriptionlsignal type
Charge indicator signal (terminal
61)
Voltage signal, terminal 30h
Secondam air pump relay, activation
Input
5
Signal, electric (auxiliary) cooling fan, signal
I~ot used