1998 AUDI A4 heater

24-1


Motronic Multiport Fuel
Injection (MFI) and ignition
system Component locations

Data Link Connector (DLC)
Fuel pump relay
Oxygen Sensor (O2S) behind Three Way
Catalytic Converter (TWC) -G130-, with Oxygen
Sensor (O2S) heater -Z29-
Located under knee bar, left side of steering
wheel
Position 6 on relay panel in driver's side footwell
Bank 1, sensor 2
In exhaust system behind TWC
Pa
ge 1 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1

24-2


Oxygen Sensor (O2S) 2 behind Three Way
Catalytic Converter (TWC) -G131-, with Oxygen
Sensor (O2S) heater -Z30-
EVAP system Leak Detection Pump (LDP) -
V144-
Bank 2, sensor 2
In exhaust system behind TWC
In left-rear wheelhousing behind splash shield
Pa
ge 2 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1

24-3


1 -
Harness connector
For O2S behind TWC -G130- and O2S
heater -Z29- 4-pin connector, greenFor bank 1, sensor 2
2 -
Harness connector For O2S 2 behind TWC -G131- and O2S 2
heater -Z30- 4-pin connector, brownFor bank 2, sensor 2
3 -
Harness connector For HO2S -G39- with O2S heater -Z19-4-pin connector, blackFor bank 1, sensor 1
4 -
Harness connector For Knock Sensor (KS) 1 -G61-3-pin connector, blue
5 -
Secondary Air Injection (AIR) solenoid
valve -N112-
Pa
ge 3 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1

24-4


6 -
Intake Air Temperature (IAT) sensor -G42-
7 -
Harness connector
For HO2S 2 -G108- with O2S heater -Z28-4-pin connector, blackFor bank 2, sensor 1
8 -
Harness connector For Knock Sensor (KS) 2 -G66-3-pin connector, blue
9 -
Harness connector For engine speed (RPM) sensor -G28-3-pin connector, gray
10 -
Electronics box (E-box)
Contains:Motronic Engine Control Module (ECM) -
J220- Secondary Air Injection (AIR) pump relay -
J299-
Pa
ge 4 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1

24-5


11 -
Valve 2 for camshaft adjustment -N208-
12 -
Camshaft Position (CMP) sensor -G163-,
bank 1
13 -
Heated Oxygen Sensor (HO2S) -G39- with
Oxygen Sensor (O2S) heater -Z19-
Bank 1, sensor 1
14 -
Ground (GND) connection To right engine support
15 -
Mass Air Flow (MAF) sensor -G70-
Pa
ge 5 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1

24-7


21 -
Engine speed (RPM) sensor -G28-
In transmission housing above differential
22 -
Camshaft Position (CMP) sensor -G40-,
bank 2
23 -
Heated Oxygen Sensor (HO2S) 2 -G108-
with Oxygen Sensor (O2S) heater -Z28- Bank 2, sensor 1
24 -
Knock Sensor (KS) 2 -G66-
25 -
Ignition coils and power output stage
Includes:Ignition coil -N-Ignition coil 2 -N128-Ignition coil 3 -N158-Power output stage -N122-
Pa
ge 7 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1

24-9

Safety precautions


WARNING!

Fire hazard! Do not smoke, work near
heaters or open flame, or have anything
nearby that could ignite fuel. The fuel system
is under pressure. Before opening, cover
connections with a rag, and open carefully to
release pressure.
When driving or riding in an airbag-equipped
vehicle, NEVER hold the scan tool or other
test equipment in your hands or lap while in
motion. Objects between you and the airbag
increase the risk of injury in an accident.
During a test drive in an airbag-equipped
vehicle, test equipment must always be
fastened to and operated from the rear seat
by a second technician.
Pa
ge 9 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1

24-26

Continuation
If the value in either display field 1 or 3 is NOT
OK, or if the value does not fluctuate by at least 2
%:

- Road test to condition oxygen sensor(s)
(eliminate possible contamination) and repeat
test.
If the value in either display field 1 or 3 is still
NOT OK, or if it still does not fluctuate by at least
2 %:

- Check Oxygen Sensor (O2S) heater(s) page
24
-34
.
If the value in either display field 1 or 3 remains
constant:

- Check oxygen sensor voltage(s) (display fields 2
and 4).

-
Press button.
- Press buttons -0- and -6- to select "End Output"
function 06, and press -Q- button to confirm
input.

Pa
ge 34 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1