heater AUDI A4 1998 B5 / 1.G APB Engine Motronic Multiport Fuel Injection System Servising Workshop Manual

Fire hazard! Do not smoke, work near
heaters or open flame, or have anything
nearby that could ignite fuel. The fuel system
is pressurized. Before loosening hose
connections or opening the test connection
(to measure fuel pressure), place a cloth
around the connection. Then release
pressure by carefully opening the
connection.
Pa
ge 2 of 90 Motronic Multi
port Fuel In
jection
(MFI
) system, servicin
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24-6


Repair Manual, Fuel Supply System, Repair
Group 20, Components of EVAP system servicing
F - Electronic Power Control (EPC)
warning light
In instrument cluster (Significance of light
Page 24
-139
)
G - Leak Detection Pump (LDP) -V144
Below left rear wheelhousing liner
H - Oxygen Sensor (O2S) Behind Three
Way Catalytic Converter (TWC) -G130
with Heater for Lambda-probe 1 -Z29
This oxygen sensor is accessible from
below when vehicle is lifted
I - Oxygen Sensor (O2S) 2 Behind Three
Way Catalytic Converter (TWC) -G131
with Heater for Lambda-probe 2 -Z30 This oxygen sensor is accessible from
below when vehicle is lifted
Pa
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port Fuel In
jection
(MFI
) system, servicin
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24-7


1 -
Harness connector forOxygen Sensor
(O2S) Behind Three Way Catalytic
Converter (TWC) -G130 and Heater for
Lambda-probe 1 -Z29
4-pin green
2 -
Harness connector forOxygen Sensor
(O2S) 2 Behind Three Way Catalytic
Converter (TWC) -G131 and Heater for
Lambda-probe 2 -Z30 4-pin brown
3 -
Harness connector for Heated Oxygen
Sensor (HO2S) and Oxygen Sensor (O2S)
Heater 4-pin black
4 -
3-pin harness connector For Knock sensor (KS) 1 -G61
5 -
Engine Coolant Temperature (ECT)
Sensor -G62 On cooling pipe behind cylinder bank 1
6 -
Wastegate Bypass Regulator Valve -N75
7 -
EVAP Canister Purge Regulator Valve -
N80
Pa
ge 9 of 90 Motronic Multi
port Fuel In
jection
(MFI
) system, servicin
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11/22/2002 htt
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yp
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24-9


12 -
Recirculating valve for turbocharger -
N249
13 -
Fuel pressure regulator
14 -
Camshaft Position (CMP) Sensor 2 -G163
Cylinder bank 2Previously identified as Camshaft Position
(CMP) Sensor 2 -G40
15 -
Secondary Air Injection (AIR) Pump Relay
-J299 Only on vehicles with automatic
transmission
16 -
Motronic Engine Control Module (ECM) -
J220
17 -
3-pin harness connector For Engine Speed (RPM) Sensor -G28grey
18 -
3-pin harness connector For Knock Sensor (KS) 2 -G66
19 -
Harness connector for Heated Oxygen
Sensor (HO2S) 2 -G108 and Oxygen
Sensor (O2S) Heater -Z28 4-pin black
Pa
ge 11 of 90 Motronic Multi
port Fuel In
jection
(MFI
) system, servicin
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pair&id=AUDI.B5.FU04.24.1

24-11


26 -
Valve -1- for camshaft adjustment -N205
27 -
Heated Oxygen Sensor (HO2S) -G39 with
Oxygen Sensor (O2S) Heater -Z19
28 -
Knock Sensor (KS) 1 -G61
29 -
Knock Sensor (KS) 2 -G66
30 -
Engine Speed (RPM) Sensor -G28
In transmission above sensor wheel
31 -
Heated Oxygen Sensor (HO2S) 2 -G108
and Oxygen Sensor (O2S) Heater -Z28
Pa
ge 13 of 90 Motronic Multi
port Fuel In
jection
(MFI
) system, servicin
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11/22/2002 htt
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play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.1

24-19


WARNING!
Fire hazard! DO NOT smoke or work near
heaters of have anything in the area that can
ignite fuel. The fuel system is pressurized.
Before loosening hose connections or opening
the test connection), place a cloth around the
connection.
Install intake manifold in reverse order. (Tightening
torque of bolts: 10 Nm) 15 -
Loosen indicated hose. This hose leads to
the suction side of turbocharger bank 1.
16 -
Loosen fuel return line from fuel rail
(catch escaping fuel with clean rag).
17 -
Loosen fuel supply line from fuel rail.
18 -
Loosen indicated hose at EVAP valve.
- Unbolt intake manifold from cylinder
heads and carefuly lift intake manifold
from cylinder heads.
Pa
ge 21 of 90 Motronic Multi
port Fuel In
jection
(MFI
) system, servicin
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24-48

Checking for leaks

- Bridge sockets 1 and 65 on the test box using
test leads from VAG1594 A connector test kit.
(This creates an Ground (GND) connection to
one side of the fuel pump relay coil.)

Note:
Once the socket are bridged the fuel pump runs
continuously, even if the engine is not running.
This is because the fuel pump relay receives its
positive voltage supply via the central electrics.
The negative voltage supply for the fuel pump
relay comes via the cable bridge on the test box.

WARNING!

Fire hazard. DO NOT smoke or work near
heaters or have anything in the area that can
ignite fuel!

- Check injectors fuel for leaks (visual check).
When fuel pump is running, only 1 or 2 drops
should escape per minute from each injector.

- If fuel loss is greater, switch off fuel pump
(remove bridge) and replace faulty injector
Page 24
-53
, also observe notes on Page 24
-
53
.
Pa
ge 57 of 90 Motronic Multi
port Fuel In
jection
(MFI
) system, servicin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.1