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Maintenance
Table b. Inspection I Service (continued)
I I I I
Warm engine Dealer service
required recommended
Check windshield
washer fluid level and
antifreeze protection.
Add washer fluid as necessary.
Replace ventilation
microfilter. (Note:
reduce replacement intervals in dusty
operation conditions)
Reset Service interval Indicator
(Sil).
Additional
repair
information
Tools Required
*
eck aim of washer jets and adjust if
necessary.
covers, obvious damage or attachment o
s or accessories.
Road test
Check braking performance, steering,
heating and air conditioner operation.
Check manual transmission and clutch
operation or automatic transmission
operation. New
parts
required
*
Bodylelectrical
121
630
630
Checic battery state of charge
Check operation of:
headlights,
parking iights, back-up lights.
license plate lights, interior lights,
glove box
illumination, engine compartment light,
trunk light, turn signals, emergency
flashers, stop iights.
Check operation of horn and headlight
dimmer switch
:i:
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Cylinder Head Removal and Installation / -
< Use a spanner tool to rotate exhaust sprocket until stop on in-
take sprocket is contacted.
- Slide VANOS control unit forward to remove
Remove primary chain tensioner (arrow)
WARNING -
Remove tensioner slowly - it is under spring pressure. I
- Working at the intake side of cylinder 1 :
Detach electrical harness connector for camshaft position
sensor and remove sensor.
Detach electrical harness connector for coolant tempera-
ture sensor.
- Remove exhaust manifolds. D~scard nuts. See 180 Exhaust
System.
Disconnect heating system hoses (arrows) from back of cyl-
inder head.
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121-9
Battery, Starter, ~lternatorl
Battery charging
Discharged batteries can be recharged using a batterycharg-
er. Remove the battery from the trunk during charging.
Prolonged charging causes electrolyte evaporation to a level
that can damage the battery. It is best to use a low-current
charger
(6 amperes or less) to prevent battery damage
caused by overheating.
WARNING -
Hydrogen gas given off by the battery during charging is ex-
plosive. Do not smoke.
Keep open flames away from the top
ofthe batte~ and prevent electrical sparks by turning off the
battery charger before connecting or disconnecting it.
Battery electrolyte (sulfuric acid) can damage the car. If
electrolyte is spilled, clean the area with a solution
ofbak-
ing soda and water.
Always allow a frozen battery to thaw before attempting
to recharge it.
Always disconnect both battery cables and remove bat-
tery from vehicle during battery charging. Do not ex-
ceed
16.5 charging voltage at the battery
Battery safety terminal, replacing
If the battery safety terminal has been triggered, investigate
and correct the cause prior to replacement.
- Working in right side of luggage compartment, remove bat-
tery trim panel.
- Disconnect negative (-) battery terminal and cover with
insulator.
- Disconnect positive (+) cable from battery.
- Release positive (+) cable from cable brackets on luggage
compartment wall. Lay new repair cable parallel to positive
cable.
- Mark off length of new cable on old cable. Allow 10 cm
(2.5 in) of slack.
- Saw through old cable.
Do not use bolt cutters or similar tools to cut through cable.
A cable end that has been squashed
flat will not fit into the
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Fuel Injection I
Mass air flow (MAF) sensor,
checking and replacing
4 The hot film mass air flow (MAF) sensor (arrow) sends a
varying voltage (approx.
0.5 - 4.5 vdc) to the ECM represent-
ing the measured intake air. The air mass input signal is pro-
duced electronically by the
MAFsensorusing a heated metal
film in the air flow stream.
The ECM relay provides the operating voltage to the MAF
sensor. As air flows through the MAF sensor, the film is
-
cooled. To maintain the film at a constant temperature, addi-
tional heating current is necessary. It is this additional current
that is the basis for the input signal.
If there is no output signal from the MAF sensor, the ECM op-
erates the engine using throttle position and engine rpm in-
puts. A faulty MAF sensor illuminates the MIL.
A faulty MAF sensor can produce the following problems:
Difficult to restart when engine is hot.
Engine starts then stalls.
Engine starts and runs only with accelerator pedal de-
pressed.
Disconnect electrical harness connector from MAF sensor
(arrow).
- Turn ignition on and check for voltage and ground at connec-
tor.
There should be ground at pin
1 and battery voltage at pin
3.
If any faults are found, check for wiring breaks between
MAF sensor and ECM and between MAF sensor and ECM
relay.
NOTE-
Visually inspect the sensor for damage, missing or blocked
screens. The screens affect air flow calibration. Also inspect
the sealing O-rings where the sensor inserts into the air
filter
housing and intake boot. Ensure the pin connections are
clean and tight.
4 Connect a BMW-compatible scan tool or an OBD II generic
scan tool. Check air mass signal (load signal) with the engine
at idle. Raise idle speed and check that load signal changes
with rpm.
CA UTIOI\C
Be sure ignition is OFFbefore disconnecting or reconnecting r
1 DME svstem components. 1
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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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.. .-
/Fuel lnjeciion
NOJE-
With engine oft disconnect harness connector and checlc
heating element resistance between white wires on the sen-
sor side of harness. If the element is electrically open (no
continuity), replace sensor.
- If oxygen sensor does not produce a fluctuating voltage and
preheater circuit is
OK, replace sensor.
NOJE-
If not already applied, coat oxygen sensor threads w~th anti-
seize compound before installat~on. Do not get the com-
pound on the sensor tip.
Tightening torque Oxygen sensor to exhaust system
55 Nm (41 ft-lb)
Fuel injectors, checking and replacing
The fuel iniectors are switched on and off (oaened and
closed)
by'the ECM. The injectors are connkcted to acom-
mon power source. A ground signal from the ECM is used to
open and close the injectors.
CA U JIOG
Use only a digital multimeter or an LED injector tester when
testing injectors or wiring. Use of an analog
VOM or incan-
descent test light may damaqe the engine controlmodule.
4 Remove fuel rail cover. See 110 Engine Removal and in-
stallation.
With the engine running, place the point of a long screwdriver
on each injector and check for a cliclting vibration.
If no vibra-
tion is found do the voltage
checit shown below.
Injector electrical loom removal:
- Loosen mounting nuts A.
Remove ground wire C.
Disconnect ignition coil harness D
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130-59
Fuel Injection
:-- -i. Evaporative emissions
1.
control diagram (M5.2.1)
i 1
i I @ 1. ECM r.=.:-:, 2. Purge valve
3. Leak detection pump (LDP)
4. Liquid vapor separator
5. Purge canister
6. Filter
Bosch M5.2 ECM pin assignments
(M62 up to 911997)
Tabled. Bosch M5.2 ECM pin assignments
I' 1- 1. . . -
4 1 output / Cyl. 4 fuel injection valve I Cyl. 4 fuel injection valve (cycled ground)
Pin
1
2
3
i I
I
7 / output I Cyl. 6 fuel injection valve I Cyl. 6 fuel injection valve (cycled ground)
Type
output
output
output
I I ,
8 1 output I Malfunction indicator light (MIL) (USA only) I lliumlnated for exhaust gas related diagnostic trouble code
5
Component/function
Oxygen sensor heater signal
Idle speed control -closing winding
Cvl. 1 fuel iniection valve Note
DME heated oxygen sensor
1 splice
idle speed control valve (cycled ground)
Cvl. 1 fuel iniection valve lcvcled around)
6 1 ground I Fuel injection valve ground 1 Ground
output
9
Not
used
Not used
11
12
13
Cyl. 5 fuel injection valve
10 1 input I Electronic immobilizer (EWS) / Electronic immobilizer (EWS) control unit
input
Heated oxygen sensor signal Cyl.
5 fuel injection
valve (cycled ground)
output
input
input
16
Start signal Starter relay
NC compressor signal
Terminal
50 signal
Knock sensor signal
17 1 ground I Hot film mass air flow (MAF) sensor ground I Hot film mass air flow (MAF) sensor ground
output Heating and
A/C control module
Ignition switch
Knock sensor
Intake air temperature intake air temperature sensor (voltage value)
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Fuel Injection
I 68 1 / Not used
Table
d. Bosch
M5.2 ECM pin assignments
I I I
69 1 input I AIC system standby signal (> 10 V) 1 Heating and AIC control module
Pin
57
58
59
60
61
62
63
64
65 66
67
Type
input
input
input
input
I 70
72
73
74
Componentlfunction
Not used
Not used
Heated thermostat (characteristic map, cooling)
Programming voltage input (voltage
value)
Signal input Evaporative emission valve
Not used
Fuel pump relay (ground)
Not used
Not used
Not used
Not used
75
76
77
78
79
80
Note
Characteristic map, cooling
Data
llnlc connector
Evaporative emission valve
Fuel pump relay
71 1 ground I Control module ground I Ground splice
input
input
81
input input
input
input
output Not used
I
Knock sensor signal
Not used
Not used
Coolant temperature
82 1 I Not used
83
I I
Knock sensor
Dual temperature
swltch
Not used
Heated oxygen sensor signal (voltage
0.1-1.0 V)
Heated oxygen sensor
signal (voltage 0.1-1.0 V)
Crankshaft position sensor signal (speed and
position, AC voltage)
Right rear wheel speed signal
TD signal (engine speed)
85
I I I
Heated oxygen sensor II behind catalytic converter
Heated oxygen sensor
I behind catalytic converter
Cranitshaft positionlrpm sensor
ABSIASC control module
TD signal splice
84 1 / Not used 1
output
88
86
1 input-output 1 CAN-Bus high I Transmission conlrol module (AGS)
input-output
Injection signal
input-output Integrated instrument cluster control
module (IKE)
CAN-Bus low Transmission control module (AGS)
Data
linlc TxD Data link connector