1998 AUDI A4 fuel pressure

01-19

Diagnostic Trouble Code
(DTC) Malfunction text
MIL switching
condition
SAE
VAG
P0322 16706 Ignition/Distributor Engine Speed Input Circuit No Signal immediately
P0327 16711 Knock Sensor 1 Circuit Low Input (Bank 1 or Single Sensor) immediately
P0332 16716 Knock Sensor 2 Circuit Low Input (Bank 2) immediately
P0337 16721 Crankshaft Position Sensor Circuit Low Input immediately
P0401 16785 Exhaust Gas Recirculation Flow Insufficient Detected 2 Trips
P0402 16786 Exhaust Gas Recirculation Flow Excessive Detected 2 Trips
P0422 16806 Main Catalyst Efficiency Below Threshold (Bank 1) 2 Trips
P0432 16816 Main Catalyst Efficiency Below Threshold (Bank 2) 2 Trips
P0440 16824 Evaporative Emission Control System Malfunction 2 Trips
P0452 16836 Evaporative Emission Control System Pressure Sensor Low
Input immediately
P0453 16837 Evaporative Emission Control System Pressure Sensor High
Input immediately
P0461 16845 Fuel Level Sensor Circuit Range/Performance immediately
P0501 16885 Vehicle Speed Sensor Range/Performance immediately
Pa
ge 30 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

01-52

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
ge 70 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

01-55

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
ge 77 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

01-59

Output on GST and/or on VAG
1551 scan tool Possible malfunction
cause
Malfunction repair
P0175 / 16559
System too Rich (Bank 2) Malfunction P0172 /
16556
"System too Rich (Bank 1)"
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 2)
does not close or leaks

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

For troubleshooting Display
groups 006, 008, 009 and 010
Malfunction cause found:
Yes


- Erase DTC memory, test drive and check
DTC memory again
Notes:
If the malfunction "P0175 / 16559" 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 83 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

01-61


Fuel system pressure too low because of:
- Leaks in the area of the fuel lines or the fuel distributor strip
- Vacuum line to the fuel pressure regulator or fuel pressure
regulator faulty
- Fuel filter plugged
- Fuel pump delivery quantity too low

- Check system pressure and residual pressure
page 24
-20


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and check DTC
memory

EVAP canister purge regulator valve -N80- sticks
mechanically in closed position

- Check EVAP canister purge regulator valve -
N80- page 24
-58


Malfunction cause found: Yes


- Erase DTC memory, test drive and check DTC
memory
Notes:
If the malfunctions "P0171 / 16 555 and P0174 / 16558"are set, 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 85 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

01-64


Combustion misfiring has been stored in the DTC
memory for several or all cylinders

- Leaks in intake system check intake system for air
leaks - Fuel pressure not OK Check system and residual
pressure page 24
-20

- Exhaust gas recirculation too high check EGR
system hoses and components - Carbon deposits on fuel injectors check- Carbon deposits on intake valves

Malfunction cause found: Yes


- Erase DTC memory, test drive and check DTC
memory
Notes:

The malfunction "P0300 / 16684" is set as soon as combustion misfiring has been recognized in more than one cylinder.
If there is combustion misfiring with low misfiring rate, the MIL is only set after two successive trips without preceding cold
start and the malfunction occurring.
Combustion misfiring with high misfiring rate is displayed immediately by the MIL blinking, since the Three Way Catalytic
Converter (TWC) can be damaged. In this case, driving should be continued with reduced power and the malfunction
should be repaired as quickly as possible.
Pa
ge 88 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

01-67


Combustion misfiring on several or all cylinders
stored in the DTC memory

- Leaks in intake system check intake system for air
leaks - Fuel pressure not OK check system and residual
pressure page 24
-20

- Exhaust gas recirculation too high check EGR system
hoses and components - Carbon deposits on fuel injectors check- Carbon deposits on intake valves check

Malfunction cause found: Yes


- Erase DTC memory, test drive and check DTC memory
Notes:

The malfunction "P0300 / 16684" is set as soon as combustion misfiring has been recognized on one or more cylinders.
If there is combustion misfiring with low misfiring rate, the MIL is only switched on after two successive trips without
preceding cold start and malfunction occurring.
Combustion misfiring with high misfiring rate is displayed immediately by the MIL light blinking since the Three Way
Catalytic Converter (TWC) can be damaged. In this case, driving should continue with reduced power and the malfunction
should be repaired as quickly as possible.
Pa
ge 91 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