sensor AUDI A4 1996 B5 / 1.G AFC Engine On Board Diagnostic Multiport Fuel Injection Owner's Guide

01-47

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

Malfunction repair
P0154 / 16538
O2 Sensor Circuit No
Activity Detected (Bank 2
Sensor 1) Harness connector for Heated Oxygen
Sensor (HO2S) 2 -G108- (B2-S1) 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 check
DTC memory again
MIL Status:
MIL lights up immediately
Wiring connection to Heated Oxygen
Sensor (HO2S) 2 -G108- (B2-S1) faulty, or
HO2S 2 -G108- faulty

- Check HO2S 2 -G108- (B2-S1) page 24
-49


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and check
DTC memory again
For troubleshooting
Display group 010
Engine Control Module (ECM) -J192-
faulty

- Replace and code engine control module
page 01
-265
erase DTC memory
and test drive check DTC memory
Notes:
The malfunction "P0154 / 16538" is set 123 sec. after engine start and engine temperature over 30 C (86 F), as soon as the
signal voltage lies between 370 mV and 430 mV for longer than 4 sec.
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01-48

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

Malfunction repair
P0155 / 16539
O2 Sensor Heater Circuit
Malfunction (Bank 2
Sensor 1) Harness connector for Oxygen Sensor
(O2S) heater -Z28- (B2-S1) 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 check
DTC memory again
MIL Status:
MIL lights up immediately
Wiring connection for Oxygen Sensor
(O2S) heater -Z28- (B2-S1) faulty, or heater
-Z28- faulty

- Check O2S heater -Z28- (B2-S1) page 24
-51


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and check
DTC memory again
For troubleshooting
Display group 040
Engine Control Module (ECM) -J192-
faulty

- Replace and code engine control module
page 01
-265
erase DTC memory and
test drive check DTC memory
Notes:
The heater for the O2S in front of the Three Way Catalytic Converter (TWC) is switched on by the fuel pump relay.
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jection
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01-49

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

Malfunction repair
P0156 / 16540
O2 Sensor Circuit
Malfunction (Bank 2
Sensor 2) Harness connector for Oxygen Sensor (O2S) 2
behind Three Way Catalytic Converter (TWC) -
G131- (B2-S2) 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
check DTC memory again
MIL Status:
MIL lights up
immediately
Wiring connection to Oxygen Sensor (O2S) 2
behind Three Way Catalytic Converter (TWC) -
G131- (B2-S2) faulty, or sensor -G131- faulty

- Check O2S 2 behind three way
catalytic converter -G131- (B2-S2)
page 24
-53


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
For troubleshooting
Display group 041
Engine Control Module (ECM) -J192- faulty

- Replace and code engine control
module page 01
-265
erase DTC
memory and test drive check DTC
memory
Notes:
The malfunction "P0156 / 16540" is set 123 sec after engine start, at a coolant temperature over 80 C (176 F) and 45 sec
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jection
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01-50

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

Malfunction repair
P0158 / 16542
O2 Sensor Circuit High
Voltage (Bank 2 Sensor
2) Harness connector for Oxygen Sensor (O2S) 2
behind Three Way Catalytic Converter (TWC) -
G131- (B2-S2) 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
page 24
-1

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
MIL Status:
MIL lights up
immediately
Wiring connection to Oxygen Sensor (O2S) 2
behind Three Way Catalytic Converter (TWC) -
G131- (B2-S2) faulty, or sensor -G131- faulty

- Check O2S 2 behind three way
catalytic converter -G131- (B2-S2)
page 24
-53


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
For troubleshooting
Display group 041
Engine Control Module (ECM) -J192- faulty

- Replace and code engine control
module page 01
-265
erase DTC
memory and test drive check DTC
memory
Notes:
The malfunction "P0158 / 16542" is set 3 min after engine start, as soon as the O2S voltage is greater than 1.4 volts for
Pa
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port Fuel In
jection
(MFI
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01-51

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

Malfunction repair
P0161 / 16545
O2 Sensor Heater Circuit
Malfunction (Bank 2
Sensor 2) Harness connector for Oxygen Sensor
(O2S) heater -Z30- (B2-S2) 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 page 24
-1

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
MIL Status:
MIL lights up immediately
Wiring connection for Oxygen Sensor
(O2S) heater -Z30- (B2-S2) or heater -Z30-
(B2-S2) faulty

- Check O2S heater -Z30- (B2-S2)
page 24
-55


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
For troubleshooting
Display group 040
Engine Control Module (ECM) -J192-
faulty

- Replace and code engine control
module page 01
-265
erase DTC
memory and test drive check DTC
memory
Notes:
The heater for O2S behind Three Way Catalytic Converter (TWC) is not switched on immediately at engine start, but only
when the calculated exhaust gas temperature exceeds 308 C (586 F) ( Read measuring value block, display group 42,
channel 1).
Pa
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(OBD
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jection
(MFI
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01-52

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

Malfunction repair
P0170 / 16554
Fuel Trim Malfunction (Bank 1) Air leak in the area of the intake
manifold

- Find and repair leak

Malfunction cause found: Yes
No

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

Oil dilution (fuel in the oil) because
of frequent cold starts or driving short
distances

- Check, if necessary do oil change
MIL Status:
MIL lights up after 2 Trips Malfunction cause found: Yes
No

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

Mass Air Flow (MAF) sensor -G70-
supplies false signal

- Check Mass Air Flow (MAF) sensor -
G70- page 24
-81

For troubleshooting Display
groups 005, 007, 009 and 010
Malfunction cause found: Yes
No

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

Oil burning with faulty piston

Repair Manual, 2.8 Liter V6 2V Engine
Mechanical, Engine Code(s): AFC, Repair Group 15
- Check compression pressure

Malfunction cause found: Yes

Pa
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(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

- Erase DTC memory, test drive and
check DTC memory again
Note:
The malfunction "P0170 / 16554" is set in the learning procedure as soon as the difference between a newly learned oxygen
sensor learning value and an optional stored oxygen sensor learning value is greater than 8%.
Pa
ge 71 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
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play?action=Goto&t
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01-53

Output on GST and/or
on VAG 1551 scan tool
Possible malfunction
cause
Malfunction repair
P0171 / 16555
System too Lean (Bank
1) Malfunction P0174 /
16558
"System too Lean (Bank
2)"
Also in DTC memory
No

Yes

- If the fuel-air mixture for both cylinder banks is too lean, a
malfunction must be present that leads to incorrect mixture
formation for both banks (B1 and B2) Troubleshooting
according to Diagnostic Trouble Code (DTC) page 01
-57


Malfunction cause found:
Yes
No

- Erase DTC memory, test drive and check DTC memory
again
MIL Status:
MIL lights up after 2
Trips Leak in the exhaust
system for bank 1 up to
Heated Oxygen Sensor
(HO2S) -G39-

- Find and repair leak

Malfunction cause found:
Yes
No

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

Leak in intake system

- Find and repair leak
Pa
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gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
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play?action=Goto&t
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e=re
pair&id=AUDI.B5.FU01.01.1

Notes:
If the malfunction "P0171 / 16555" is set, the oxygen sensor control has exceeded the learning value limit in the "rich"
direction, but the HO2S still recognizes "mixture too lean".
Pa
ge 75 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

01-55

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

Malfunction repair
P0172 / 16556
System too Rich (Bank 1) Malfunction P0175 / 16559
"System too Rich (Bank 2)"
Also in DTC memory
No
Yes

- Fuel pressure too high; check system
pressure and residual pressure page 24
-
20


Malfunction cause found: Yes

No

- Erase DTC memory, test drive and check
DTC memory again
MIL Status:
MIL lights up after 2 Trips Fuel injector (Bank 1) does
not close and/or leaks

- Check fuel injection quantity of fuel
injectors and for leaks page 24
-33

For troubleshooting Display
groups 005, 007, 009 and 010
Malfunction cause found: Yes



- Erase DTC memory, test drive and check
DTC memory again
Note:
If the malfunction "P0172 / 16556" is set, the oxygen sensor control has dropped below the learning value limit in the "lean"
direction, but the (HO2S) still recognizes "mixture too rich".
Pa
ge 76 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