
Downloaded from www.Manualslib.com manuals search engine 
130-46 
Fuel Injection 
When  system  faults are detected, a  diagnostic trouble code 
(DTC)  is stored  in the  engine  control module  (ECM). The MIL 
also  illuminates  if an emissions-related  fault  is detected. 
When  faults arise,  or 
if the malfunction indicator lamp  (MIL) is 
illuminated,  begin troubleshooting  by connecting  BMW ser- 
vice tester 
DISplus. MoDiC, GTI or  equivalent scan tool.  The 
capabilities  of 
OED II software has  the potential  to save hours 
of  diagnostic  time and to help  avoid  incorrect component  re- 
placement  and possible  damage to  system components. 
CA UTIOiU- 
The tests  in this section  may set fault codes (DTCs) in the 
ECM  and illuminate the MIL.  After ail testing is  completed, 
access  and clear  DTC  fault 
memory using an OED I/ or 
BMW  compatible  scan tool. See OBD  On-Board  Diag- 
nostics. 
Only  use a digital 
multimeter for electrical  tests. 
Relay  positions  can vary.  Be sure to confirm  relay 
posi- 
. tion by identifying  the wiring  in the  socket using  the wir- 
ing diagrams-found in ~~~~lectrical Wiring 
Diagrams. 
NOTE- 
OED I1 fault  memory  (including  an illuminated MIL) can 
only be reset 
using~the special scan  tool. Removing  the 
connector from the  ECM or disconnecting the battery  will 
not erase  the fault 
memory. 
The  BMW-dedicated  20-pin diagnostic link connector 
(DLC)  is in the right  rear of the engine  compartment. 
The  16-pin  OBD 
I1 diagnostic connector  (arrow) is located 
inside the  car on 
the lower left dash panel.    

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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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130-50 
Fuel Injection 
Bosch M5.2 
ECM relay 
1 HoL al ail iirnel XOL a1 ail limes 
i--[-----i F109 (BOA) electronics I L.$.....: .I: 
ECM relay . . . . . . . . . , 
8,s 
:, 
6 1 .. ... ~~.~~. . ...... .-, Engine control ii~~-~.~~..~ ........ ~~~~~~.~~~~:. module relay -;I 
Of? 
,c,;,,, 
< With ignition  off, remove ECM relay  (arrow) in electronics 
box (E-box)  at right rear  of engine  compartment. 
NOTE- 
Relay locations can  vary. Conh relay identification  by 
matcliing  wiring colors  and terminal  numbers. 
4 Check for voltage  at terminal 6 of main  relay socket  (30-red 
wire).  On M5.2  cars also check  for battery  voltage  at terminal 
8. 
. . . . . . . . . , 
If  battery voltage  is present, continue  testing 
. 
If battery voltage  is not present, check  large red wire(s) in 
relay socltet. See 
ELE Electrical  Wiring Diagrams. 
%P,,tt 
- Reinstall  relay and turn  ignition on. Gain access to underside 
of  relay socket and 
checlc for  ground  at terminal 4 (85-brown 
wire). 
. . . . . . .  . . . . . - - - - - - - - - . - - - . . l ,,-. ; Engine i f .: , ; Fuse  carrier .,A . :engine /;is? /control L.!.!! .... 1.: ...... !.::..! I lij :module  electronics If 
ground is present, continue  testing 
If ground is not present, signal from  ECM is missing. Checic 
wire between  ECM and  relay. 
4 With ignition on and relay installed, check  for battery  voltage 
at terminal 
2 (87-redlwhite wire).  On M5.2.1  cars also checlc 
for battery  voltage  at terminal  5. 
If battery voltage is present, relay has energized and is 
functioning  correctly. 
If  battery  voltage  is not  present  and all earlier tests are  OK, 
relay is  faulty and should  be replaced.    

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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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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)    

Downloaded from www.Manualslib.com manuals search engine 
Fuel Injection 
When system faults are detected, a diagnostic  trouble code 
(DTC)  is stored  in the  engine  control module  (ECM). The MIL 
also illuminates 
if an emissions-related  fault is detected. 
When  faults arise,  or 
if the malfunction indicator lamp  (MIL) is 
illuminated,  begin troubleshooting  by connecting  BMW ser- 
vice  tester 
DISplus, MoDiC, GTl or equivalent  scan tool. The 
capabilities  of OBD 
II software has  the potential  to save hours 
of  diagnostic  time and to help avoid incorrect  component  re- 
placement  and possible  damage to system components. 
CA UTIOI\C 
The tests  in  this section  may set fault  codes (DTCs) in the 
ECM  and illuminate the  MIL. After all testing  is completed, 
access  and clear  DTC  fault memory  using an  OBD 
I1 or 
BMW compatible scan  tool. See OBD  On-Board  Diag- 
nostics. 
. Only use  a digital multimeter  for electrical  tests. 
Relay  positions can  vary. Be sure  to confirm  relay posi- 
tion  by identifying the  wiring in the 
socket using the wir- 
ing  diagrams  found in  ELE  Electrical  Wiring 
Diaqrams. 
NOTE- 
= OBD I1 fault memory (including  an illuminated  MIL) can 
only be reset  using the special scan tool.  Removing the 
connector  from the ECM  or disconnecting the battery  will 
not erase  the fault memory. 
0 The  BMW-dedicated  20-pin diagnostic  link  connector 
(DLC)  is in the  right rear  of the engine compartment.  The 
20-pin  DLC was eliminated  on models after 
6/2000. 
The  16-pin  OBD I1 diagnostic connector  (arrow) is located 
inside the car  on the  lower left  dash panel.    

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130-70 
Fuel Injection 
ECM relay 
-- 
CAUTION- 
Relay positions can vary Be sure  to confirm relay position  by 
identifying  the wiring  in the 
socl(et using  the wiring diagrams 
in ELE Electrical  Wiring Diagrams. 
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 unlock from bulk  head and 
remove  duct. 
Release spring 
loclt (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. 
4 With  ignition  off, remove main relay  (arrow) in electronics 
box (E-box)  at right  rear  of engine compartment. 
NOTE- 
Relay locations  can vary  Confirm  relay identification  by 
matching  wiring colors  and terminal  numbers. 
4 Check for voltage  at terminal 6 of main  relay socket  (30-red 
wire). 
If battery  voltage  is present, continue testing. 
If  battery voltage  is not present, check  large red wire  in re- 
lay socltet.  See ELE Electrical  Wiring Diagrams. 
- Reinstall  relay and turn ignition  on. Gain  access to underside 
of  relay socket  and check  for ground  at terminal 
4 (85-brown 
wire). 
If ground  is present,  continue testing. 
If  ground  is not  present, switched ground signal from  ECM 
is missing. Check wire between  ECM and  relay. 
- With ignition on and relay installed, check for battery voltage 
at terminal 
2 (87-redlwhite wire). 
If  battery  voltage  is present, relay  has energized and is 
functioning  correctly. 
If  battery  voltage is not present and all earlier tests  are OK. 
relay is faulty  and should  be replaced.