fuel AUDI A4 2000 B5 / 1.G AFC Engine On Board Diagnostic Multiport Fuel Injection Manual PDF

- 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%.
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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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(OBD
) - Multi
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jection
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)
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yp
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pair&id=AUDI.B5.FU01.01.1

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

- Erase DTC memory, test drive and check DTC memory
again
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01-54


Malfunction in spark plug(s) or ignition cable(s)
in bank 1

- Spark harness connector loose or faulty
- Check ignition cable for damage (e.g. cracks, traces of burns,
worn places)
- Check face side of spark plug

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and check DTC memory

Malfunction in the fuel injectors in bank 1
because of
- Resistance in fuel injector connectors
- Fuel injector dirty, faulty or has carbon deposits

- Check harness connector on fuel injector for tight fit
- Check fuel injection quantity and for leaks in fuel injectors
page 24
-33


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and check DTC memory

Intake valves have carbon deposits

- Check intake valves for carbon deposits, if necessary clean
valves

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and check DTC memory

Continue troubleshooting per Diagnostic Trouble Code (DTC) table page 01
-60

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jection
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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
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(OBD
) - Multi
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jection
(MFI
)
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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

01-56

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

Malfunction repair
P0173 / 16557
Fuel Trim Malfunction (Bank 2) Air leak in the area of the manifold

- Find and repair leak

Malfunction cause found: Yes
No

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

Oil diluted (fuel in the oil) because
of frequent cold starts for driving short
distances

- Check and change oil if necessary
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 006, 008, 009 and 010
Malfunction cause found: Yes
No
Continued next page

- 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 - Check compression pressure
Pa
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jection
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Group 15


Malfunction cause found: Yes


- Erase DTC memory, test drive and
check DTC memory again
Note:
The malfunction "P0170 / 16554" is set in the learning process as soon as the difference between a newly learned (HO2S)
learning value and any optional stored oxygen sensor learning value is greater than 8%.
Pa
ge 78 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

01-57

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

Yes

- If the fuel-air mixture is too lean for both cylinder banks, a
malfunction must be present that leads to faulty mixture
formation for both banks (B1 and B2) Troubleshooting
per Diagnostic Trouble Code (DTC) table, page 01
-53


Malfunction cause found:
Yes
No

- Erase DTC memory, test drive and check DTC memory
again
MIL Status:
MIL lights up after 2
Trips Leaks in the intake
system for bank 2 up to
Heated Oxygen (HO2S)
sensor 2 -G108-

- Find and repair leak

Malfunction cause found:
Yes
No

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

Leaks in intake system

- Find and repair leak
Pa
ge 79 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

For troubleshooting
Display groups 006,
008, 009 and 010
Malfunction cause found:
Yes
No
Continued next page

- Erase DTC memory, test drive and check DTC memory
again
Pa
ge 80 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