1997 AUDI A4 sensor

24-13


36 -
Fuel Injectors
Cylinder bank 1Cylinder 1 Fuel Injector -N30Cylinder 2 Fuel Injector -N31Cylinder 3 Fuel Injector -N32
37 -
Ignition coils cylinder bank 1 Ignition Coil -NIgnition Coil 2 -N128Ignition Coil 3 -N158
38 -
Mass Air Flow (MAF) Sensor -G70
Pa
ge 15 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

24-14

Component location for exhaust temperature
sensors on vehicle with automatic
transmission:

Fig. 1 Component location for exhaust temperature sensors on
vehicle with automatic transmission:
1 - Sensor -1- for exhaust temperature -G235
2 - Sensor -2- for exhaust temperature -G236
Pa
ge 16 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

24-16


2 -
Disconnect harness connector from EVAP
Canister Purge Regulator Valve -N80.
3 -
Loosen both exhaust temperature
sensors -G235 and -G236 from intake
manifold. The sensors remain connected.
Ensure Ground cable is tight when
installing.
4 -
Loosen hose to brake booster at
bulkhead.
Pa
ge 18 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

24-18


Repair Manual, 2.7 Liter V6 5V BiTurbo Engine
Mechanical, Engine Code(s): APB, Repair Group 15
9 -
Disconnect harness connector at Throttle
Valve Control Module -J338.
10 -
Disconnect harness connector at Charge
Air Pressure Sensor -G31.
11 -
Remove indicated pressure hoses 12 -
Loosen indicated hose, this hose leads to
bypass valve.
13 -
Disconnect harness connector at Intake
Air Temperature (IAT) Sensor -G42.
14 -
Loosen indicated hose, (crankcase
ventilation hose).
Pa
ge 20 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

24-59

Mass Air FLow (MAF) sensor -G70,
checking


Requirements

Coolant temperature at least 80 C (175 F)

Electrical consumers switched off (radiator
fan must not run during test)
A/C switched off
Fuse for mass air flow sensor OK

Electrical Wiring Diagrams, Troubleshooting &
Component Locations

Checking function

- Connect vehicle diagnostic, testing and
information system VAS5051 or VAG1551 scan
tool and select engine electronics control
module by entering address word "01" Page
01
-9 . When doing this the engine must be at
idle.
Pa
ge 69 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

24-61

Note:
Read measuring value block display group 2 as
described in repair manual and evaluate it
Page 24
-69
. If the suggested repair steps refer
to the voltage supply test for the Mass Air Flow
(MAF) sensor or the wiring connections from the
Mass Air Flow (MAF) sensor to the Engine
Control Module (ECM), proceed to the following
pages.
Please note the distinction between sensors
made by Bosch and those made by Hitachi
(recognizable via the writing on the sensor).

Voltage supply for Mass Air Flow (MAF)
sensor, checking (Hitachi MAF sensor)

Note: For Bosch Mass Air Flow (MAF)
sensors see page Page 24
-65
.

- Disconnect connector from Mass Air Flow (MAF) sensor.
Pa
ge 71 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

24-62

- Connect multimeter to terminal 2 of connector
and engine Ground (GND) for voltage
measurement.

- Operate starter briefly.

Specification: approx. battery voltage

Note:
Voltage is supplied to Mass Air Flow (MAF)
sensor from Fuel Pump (FP) relay.
If there is no battery voltage.

- Check wire connection from terminal 2 of
connector to Fuel Pump (FP) relay via fuse for
open circuit and short circuit to Ground (GND),
repair if necessary.

Electrical Wiring Diagrams, Troubleshooting &
Component Locations
Pa
ge 72 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

24-64

Wire connections for Mass Air Flow (MAF)
sensor, checking (Hitachi MAF sensor)

Note:
Signal wire is also checked during wire test.

- Connect VAG1598/31 test box at wiring harness
to ECM, do not connect ECM Page 24
-20
.

The following wire connections must be checked for short circuit to B+,
Ground (GND) and for open circuit Connector for Mass Air Flow (MAF)
sensor -G70-
VAG1598/31 test box
terminal
1 53
3 27
4 29
Pa
ge 74 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