display AUDI A4 1997 B5 / 1.G AFC Engine On Board Diagnostic Multiport Fuel Injection Repair Manual

01-72

Output on GST and/or
on VAG 1551 scan tool
Possible malfunction cause

Malfunction repair
P0332 / 16716
Knock Sensor 2 Circuit
Low Input (Bank 2) Malfunction P0327 / 16711 "Knock
Sensor 1 Circuit Low Input (Bank 1 or
Single Sensor)" also in DTC memory
No
Yes

- Check knock sensor 1 -G61- and knock
sensor 2 -G66- page 28
-29


Malfunction cause found: Yes
No

- Erase DTC memory, test drive, and after
test drive, check DTC memory again
MIL Status:
MIL lights up
immediately
Harness connector for Knock Sensor
(KS) 2 -G66- loose or corroded due to
moisture in the harness connector

- Check harness connector for tight fit and
contact corrosion, if necessary reconnect
and/or clean, installation location page 24
-
1

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and after test
drive, check DTC memory again
For troubleshooting
Display group 016
Knock Sensor (KS) 2 -G66- loose

- Check mounting of knock sensor 2 -G66-
and if necessary retighten use insert 3247;
tightening torque 20 Nm (15 ft lb)

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and after test
drive, check DTC memory again
Pa
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01-76

Output on GST and/or on
VAG 1551 scan tool Possible malfunction cause

Malfunction repair
P0401 / 16785
Exhaust Gas Recirculation
Flow Insufficient Detected EGR system vacuum hose kinked or fallen
off

- Check vacuum hoses

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
after test drive, check DTC memory
again
MIL Status:
MIL lights up after 2 Trips Leak in a vacuum hose of the EGR system
(e.g. cracked, worn though, etc.)

- Check vacuum hoses for leaks

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
after test drive, check DTC memory
again

Vacuum hose between EGR vacuum
regulator solenoid valve -N18- and mechanical
EGR valve plugged

- Check vacuum hoses for
obstructions
For troubleshooting
Display group 017
Malfunction cause found: Yes
No
Continued next page

- Erase DTC memory, test drive and
after test drive, check DTC memory
again
Pa
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yp
e=re
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01-78

Output on GST and/or on
VAG 1551 scan tool Possible malfunction cause

Malfunction repair
P0402 / 16786
Exhaust Gas Recirculation
Flow Excessive Detected Vacuum line incorrectly connected
and/or hose connections transposed

- Check EGR system vacuum hose
according to vacuum plan page 24
-111


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and after
test drive, check DTC memory again DTC
memory
MIL Status:
MIL lights up after 2 Trips EGR vacuum regulator solenoid
valve -N18- stuck in open position

- Check EGR vacuum regulator solenoid
valve -N18- page 24
-67


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and after
test drive, check DTC memory again DTC
memory

EGR valve leaks or is stuck in
open position

- Check mechanical EGR valve page 24
-
70

For troubleshooting Display
group 017
Malfunction cause found: Yes


- Erase DTC memory, test drive and after
test drive, check DTC memory again
Notes:
Pa
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jection
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yp
e=re
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01-79

Output on GST and/or on
VAG 1551 scan tool Possible malfunction cause

Malfunction repair
P0422 / 16806
Main Catalyst Efficiency
Below Threshold (Bank 1) Are other malfunctions stored in the DTC
memory?

No

Yes

- First correct these malfunctions
according to Diagnostic Trouble Code
(DTC) table.
MIL Status:
MIL lights up after 2 Trips Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
after test drive, check DTC memory
again

Bank 1 Three Way Catalytic Converter
(TWC) chemically or thermally aged or
mechanically destroyed

- Replace Three Way Catalytic
Converter (TWC) Bank 1
For troubleshooting
Display groups 035, 036,
044
Malfunction cause found: Yes


- Erase DTC memory, test drive and
after test drive, check DTC memory
again
Note:

With the help of the Oxygen Sensor Probe in front of and behind the Three Way Catalytic Converter (TWC), the rate of
Three Way Catalytic Converter (TWC) deterioration is determined using the Three Way Catalytic Converter (TWC) oxygen
storage capability.
Pa
ge 107 of 366 On Board Dia
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jection
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)
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yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-80

Output on GST and/or on
VAG 1551 scan tool Possible malfunction cause

Malfunction repair
P0432 / 16816
Main Catalyst Efficiency
Below Threshold (Bank 2) Are other malfunctions stored in the DTC
memory?

No

Yes

- First repair these malfunctions
according to Diagnostic Trouble Code
(DTC) table.
MIL Status:
MIL lights up after 2 Trips Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
after test drive, check DTC memory
again

Bank 2 Three Way Catalytic Converter
(TWC) chemically or thermally aged or
mechanically destroyed

- Replace Bank 2 Three Way
Catalytic Converter (TWC)
For troubleshooting
Display groups 035, 036,
044
Malfunction cause found: Yes


- Erase DTC memory, test drive and
after test drive, check DTC memory
again
Note:

With the help of the Oxygen Sensor Probe in front of and behind the Three Way Catalytic Converter (TWC), the rate of
Three Way Catalytic Converter (TWC) deterioration is determined using the Three Way Catalytic Converter (TWC) oxygen
storage capability.
Pa
ge 108 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
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p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-82


EVAP canister purge regulator
valve -N80- sticks mechanically

- Check solenoid valve for Evaporative
Emission (EVAP) canister purge -N80- page 24
-58


Malfunction cause found: Yes
No
Continued next page

- Erase DTC memory, test drive and after test
drive, check DTC memory again
For troubleshooting
Display group 030
Sensor for EVAP canister -G172-
(differential pressure sensor) faulty

- Check Sensor for EVAP canister -G172-
(differential pressure sensor) page 24
-61


Malfunction cause found: Yes


- Erase DTC memory, test drive and after test
drive, check DTC memory again
Note:

With the help of the Sensor for EVAP canister -G172- (differential pressure sensor)the pressure is measured between the
Evaporative Emissions (EVAP) canister and solenoid valve for Evaporative Emission (EVAP) canister purge -N80- with
valve closed and open. If the difference in the two pressures is less than 4 mbar to 23 mbar (depending on air pressure),
the malfunction is set.
Pa
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jection
(MFI
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01-83

Output on GST and/or on
VAG 1551 scan tool Possible malfunction cause

Malfunction repair
P0452 / 16836
Evaporative Emission
Control System Pressure
Sensor Low Input Harness connector on sensor for EVAP
canister -G172- (differential pressure sensor)
loose or corroded due to moisture in the
harness connector

- Check harness connector for tight fit
and contact corrosion, if necessary
reconnect and/or clean

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
after test drive, check DTC memory
again
MIL Status:
MIL lights up immediately Wiring connection to sensor for EVAP
canister -G172- (differential pressure sensor)
faulty, or sensor -G172- faulty

- Check sensor for EVAP canister -
G172- (differential pressure sensor)
page 24
-61


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
after test drive, check DTC memory
again
For troubleshooting
Display group 030
Engine Control Module (ECM) -J192- faulty

- Replace and code engine control
module page 01
-265
erase DTC
memory and test drive check DTC
memory
Note:
The malfunction "P0542 / 16836" is set as soon after engine start as the differential pressure sensor signal is less than 0.1 V
Pa
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(OBD
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port Fuel In
jection
(MFI
)
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play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-84

Output on GST and/or on
VAG 1551 scan tool Possible malfunction cause

Malfunction repair
P0453 / 16837
Evaporative Emission
Control System Pressure
Sensor High Input Harness connector on sensor for EVAP
canister -G172- (differential pressure sensor)
loose or corroded due to moisture in the
harness connector

- Check harness connector for tight fit
and contact corrosion, if necessary
reconnect and/or clean

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
after test drive, check DTC memory
again
MIL Status:
MIL lights up immediately Wiring connection to sensor for EVAP
canister -G172- (differential pressure sensor)
faulty, or sensor -G172- faulty

- Check sensor for EVAP canister -
G172- (differential pressure sensor)
page 24
-61


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
after test drive, check DTC memory
again
For troubleshooting
Display group 030
Engine Control Module (ECM) -J192- faulty

- Replace and code engine control
module page 01
-265
erase DTC
memory and test drive check DTC
memory
Note:
The malfunction "P0453 / 16837" is set as soon after engine start as the differential pressure sensor signal is greater than 5.0
Pa
ge 113 of 366 On Board Dia
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(OBD
) - Multi
port Fuel In
jection
(MFI
)
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play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-85

Output on GST and/or on
VAG 1551 scan tool Possible malfunction cause

Malfunction repair
P0461 / 16845
Fuel Lever Sensor Circuit
Range/Performance Wiring connection between Engine Control
Module (ECM) -J192- and instrument panel
insert faulty

- Check fuel level signal page 24
-
107


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
after test drive, check DTC memory
again
MIL Status:
Malfunction not displayed by
MIL Malfunction on instrument cluster or fuel
level sensor

Repair Manual, Electrical
Equipment - Check instrument cluster
For troubleshooting Display
group 027
Malfunction cause found: Yes


- Erase DTC memory, test drive and
after test drive, check DTC memory
again
Note:
The malfunction "P0461 / 16845" is set with ignition on as soon as a voltage signal over 10.8 V is recognized for longer than
15 sec.
Pa
ge 115 of 366 On Board Dia
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(OBD
) - Multi
port Fuel In
jection
(MFI
)
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play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-86

Output on GST and/or on
VAG 1551 scan tool Possible malfunction cause

Malfunction repair
P0501 / 16885
Vehicle Speed Sensor
Range/Performance Wiring connection between vehicle speed
sensor and engine control module has open
circuit

- Check vehicle speed signal page 24
-97

MIL Status:
MIL lights up immediately Malfunction cause found: Yes


- Erase DTC memory, test drive and
after test drive, check DTC memory
again
For troubleshooting Display
group 019

Notes:
The malfunction "P0501/ 16885" is set after engine start as soon as, at a coolant temperature over 80 C (176 F) and an
engine speed signal between 1300 RPM and 6000 RPM the vehicle speed signal during a deceleration fuel shut off is less
than 1 km/h (1 mph). The duration of the deceleration fuel shut off must be longer than 3 sec.
Pa
ge 116 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1