display AUDI A4 1997 B5 / 1.G AFC Engine On Board Diagnostic Multiport Fuel Injection Service Manual
Page 76 of 366
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". 
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Page 77 of 366
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
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Page 80 of 366
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
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jection 
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Page 83 of 366
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
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(OBD
) - Multi
port Fuel In
jection 
(MFI
)
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yp
e=re
pair&id=AUDI.B5.FU01.01.1 
Page 84 of 366
01-60
 
Output on GST and/or on 
VAG 1551 scan tool   Possible malfunction 
cause    
Malfunction repair  
P0171 / 16555  
System too Lean (Bank 1)   Malfunction P1250 / 
17658 "Fuel Level Too 
Low" also in DTC memory  
No   
Yes 
  
- For malfunctions that can be caused by fuel problems 
(e.g. fuel system too lean), the malfunction "Fuel Level 
Too Low" is also set if there is less than 12 liters (12.7 qt.) 
fuel in the tank  check tank level and fill tank if necessary
P0174 / 16558  
System too Lean (Bank 2)  Malfunction cause found: 
Yes   
No   
  
- Erase DTC memory, test drive and check DTC memory 
again 
MIL Status:  
MIL lights up after 2 Trips   Large air leak quantity 
in intake system to Mass 
Air Flow (MAF) sensor -
G70-  
  
  - Determine cause of air leak and repair
For troubleshooting   
Display groups 005, 006, 
007, 008, 009 and 010  
Malfunction cause found: 
Yes   
No   
Continued next page  
  
- Erase DTC memory, test drive and check DTC memory 
again 
Pa
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jection 
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Page 86 of 366
01-62
 
Output on GST and/or on VAG 
1551 scan tool   Possible malfunction cause  
  
Malfunction repair  
P0300 / 16684  
Random Misfire Detected  
_______________________  
P0301 / 16685  
Cylinder 1 Misfire Detected   Malfunction P1250 / 17658 "Fuel 
Level Too Low" also in DTC memory  
No   
Yes 
  
- For malfunctions that can be caused by 
fuel problems (e.g. fuel system too lean), 
the malfunction "Fuel Level Too Low" is 
also set if there is less than 12 liters (12.7 
qt.) fuel in the tank   check tank level and 
fill tank if necessary 
_______________________  
P0302 / 16686  
Cylinder 2 Misfire Detected  Malfunction cause found: Yes    
No   
  
- Erase DTC memory, test drive and check 
DTC memory again 
_______________________  
P0303 / 16687  
Cylinder 3 Misfire Detected  
_______________________   Are other Diagnostic Trouble 
Codes (DTC) present in the DTC 
memory (e.g fuel injector, heated 
oxygen sensor probes, fuel system 
etc.) when combustion misfiring is 
recognized  
No   Yes 
  
- The combustion misfiring that has been 
recognized is a resulting malfunction from 
the stored Diagnostic Trouble Codes (DTC) 
 First repair this malfunction according to 
Diagnostic Trouble Code (DTC) table 
MIL Status:  
MIL lights up or blinks   
For troubleshooting  Display 
groups 031, 038, 039  
Malfunction cause found: Yes    
No   
Continued next page  
  
- Erase DTC memory, test drive and check 
DTC memory again 
Pa
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jection 
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Page 88 of 366
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
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) - Multi
port Fuel In
jection 
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)
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Page 89 of 366
01-65
 
Output on GST and/or on VAG 
1551 scan tool   Possible malfunction cause  
  
Malfunction repair  
P0300 / 16684  
Random Misfire Detected  
_______________________  
P0304 / 16688  
Cylinder 4 Misfire Detected   Malfunction P1250 / 17658 "Fuel 
Level Too Low" also in DTC 
memory  
No   
Yes 
  
- For malfunctions that can be caused by 
fuel problems (e.g. fuel system too lean), the 
malfunction "Fuel Level Too Low" is also set 
if there is less than 12 liters (12.7 qt.) fuel in 
the tank   check tank level and fill tank if 
necessary 
_______________________  
P0305 / 16689  
Cylinder 5 Misfire Detected  Malfunction cause found: Yes    
No   
  
- Erase DTC memory, test drive and check 
DTC memory again 
_______________________  
P0306 / 16690  
Cylinder 6 Misfire Detected  
_______________________   When combustion misfiring is 
recognized, are there other 
Diagnostic Trouble Codes (DTC) 
(e.g. fuel injector, Oxygen Sensor 
Proben, Fuel system etc.) in DTC 
memory  
No   Yes 
  
- The combustion misfiring that has been 
recognized is a resulting malfunction from 
the stored Diagnostic Trouble Codes (DTC) 
 First repair this malfunction according to 
Diagnostic Trouble Code (DTC) table 
MIL Status:  
MIL lights up or blinks  
For troubleshooting  Display 
groups 031, 038, 039  
Malfunction cause found: Yes    
No   
Continued next page  
  
- Erase DTC memory, test drive and check 
DTC memory again 
Pa
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(OBD
) - Multi
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jection 
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Page 91 of 366
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
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(OBD
) - Multi
port Fuel In
jection 
(MFI
)
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Page 94 of 366
01-70
 
Output on GST and/or on 
VAG 1551 scan tool   Possible malfunction cause  
  
Malfunction repair  
P0327 / 16711  
Knock Sensor 1 Circuit Low 
Input (Bank 1 or Single 
Sensor)   Malfunction P0332 / 16716   
"Knock Sensor 2 Circuit Low Input"  
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 check 
DTC memory again 
MIL Status:  
MIL lights up immediately  
   Harness connector for Knock Sensor 
(KS) 1 -G61- 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 
For troubleshooting 
Display group 015  
Malfunction cause found: Yes    
No   
  
- Erase DTC memory, test drive and check 
DTC memory again 
  
 Knock Sensor (KS) 1 -G61- loose  
  
- Check mounting of knock sensor 1 -G61- 
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 check 
DTC memory again 
Pa
ge 94 of 366 On Board Dia
gnostic 
(OBD
) - Multi
port Fuel In
jection 
(MFI
)
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yp
e=re
pair&id=AUDI.B5.FU01.01.1