AUDI A4 1999 B5 / 1.G AFC Engine On Board Diagnostic Multiport Fuel Injection Workshop Manual

G68- faulty Troubleshooting & Component Locations
Note on display field 4:
If no vehicle speed is shown on VAG 1551 scan tool, first make sure the vehicle speed display is OK. If vehicle speed display
is faulty, check vehicle speed sensor:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
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01-173
Display group 004 Display
shows Display/specified
value Designation
Basic
setting 4
1 2 3 4 0 2
1 = Idle air control valve at idle
HS: +14 to -16
or
AT: +10 to -20 2 = Idle speed control learning value in manual transmission (HS) at idle setting and/or
with automatic transmission (AT) in selector lever setting P or N
Variation permitted for new engines:
HS: +20 to -16AT: +16 to -20)
HS: 0
or
AT: +10 to -20 3 = Idle speed control learning value in automatic transmission (AT) in selector lever
setting D, 1, 2, 3 or R. (0 is always displayed in vehicles with manual transmission.)
001 10 4 = Shift inputs at idle:
0 off 1 on
Notes:

Values in display fields 2 and/or 3 can only be evaluated with idle air control valve is within tolerance at idle (display value
1). If the idle air control valve is not within tolerance after 1 minute waiting time, no learning takes place in display fields 2
and/or 3 .
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Positive learning values show a greater learning value than in the basic setting: -N71- is further open.
Negative learning values show a learning value that is less than in basic setting: -N71- is more closed.
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01-174
Test table display group 004 Display
field Display on VAG
1551 scan tool Malfunction cause
Malfunction repair
1 Outside tolerance
range
Malfunction in the DTC memoryClosed Throttle Position (CTP) switch -
F60- activated or faulty Idle Air Control (IAC) valve -N71- faulty Electrical consumers onSteering wheel at end stop Driving mode selected (automatic
transmission) Throttle sticks, floor mat presses on
accelerator pedal, air leak - Check DTC memory page 01
-13
- Check -F60- page 24
-73
and display
group 002, display field 4
- Check -N71- page 24
-37
- Switch electrical consumers off
- Center steering wheel
- Move selector lever to P or N
- Repair cause
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01-175

Display
field Display on
VAG 1551 scan
tool Malfunction cause
Malfunction repair
2 Greater than
+14(HS)
and/or
greater than +
10(AT)
Idle Air Control (IAC) valve -N71- faulty
Electrical consumers on
Steering wheel at end stop
Driving mode selected (automatic transmission)
Intake manifold pump plugged in automatic transmission
EGR vacuum regulator solenoid valve -N18- open- Check DTC memory
page 01
-13
and/or display
group 018
- Switch electrical
consumers off
- Center steering wheel
- Move selector lever to P or
N
- Repair cause
- Check DTC memory
and/or display group 017,
display field 3
2 Less than -16
(HS)
and/or
less than -20
(AT)
Idle Air Control (IAC) valve -N71- faulty
Large air leak, manifold area, throttle stop not OK
Air leak on second stage of throttle - Check DTC memory
page 01
-13
and/or display
group 018
- Repair cause
3 Outside
tolerance range Only on vehicles with automatic transmission:

Display field 2 outside tolerance
If display field 2 is within tolerance, move selector lever to D Display field 2
- Check transmission
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and observe idle for approx. 1 min.; if display field 3 stays
outside tolerance, the transmission is hard to move
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01-176

Display
field Display on VAG 1551
scan tool Malfunction cause
Malfunction repair
4 Not 001 10
Closed Throttle Position (CTP) switch -F60 activated or faulty A/C compressor switched on Rear window heating switched on Driving mode selected (automatic
transmission) - Check and adjust -F60- page 24
-
73

- Switch A/C off
- Check A/C compressor shut-off
page 24
-90

- Move selector lever to P or N
Note:
Display field 4 (shift inputs) can be used to recognize whether the components described below are recognized by the Engine
Control Module (ECM) as switched on or off. Display group 023 gives an exact description of the shift inputs. 0
0
1

1
0
Meaning of 5-digit shift inputs

1 = Shifting Signal (0 = not active / 1 = active)

2 = Gear recognition signal (always "1" except that display = "0" for automatic transmission vehicles with
gear engaged)

3 = -----------

4 = Mechanical Closed Throttle Position (CTP) switch (1 = closed / 0 = open)

5 = A/C compressor OFF/ON (0 = off, 1 = on)

6 = Rear window heater signal (always "0" except for vehicles without A/C and with rear window heater
on)
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jection
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01-177
Display group 005 Display shows
Display/specified value
Designation
Basic setting 5
1 2 3 4 -25% to +25% 1 = Oxygen sensor learning value-idle (bank 1)
-25% to +25% 2 = Oxygen sensor learning value-partial throttle 1 (bank 1)
-25% to +25% 3 = Oxygen sensor learning value-partial throttle 2 (bank 1)
-25% to +25% 4 = Oxygen sensor learning value-partial throttle 3 (bank 1) Display group 006 Display shows
Display/specified value
Designation
Basic setting 6
1 2 3 4 -25% to +25% 1 = Oxygen sensor learning value-idle (bank 2)
-25% to +25% 2 = Oxygen sensor learning value-partial throttle 1 (bank 2)
-25% to +25% 3 = Oxygen sensor learning value-partial throttle 2 (bank 2)
-25% to +25% 4 = Oxygen sensor learning value-partial throttle 3 (bank 2) Notes:

Positive learning value (+ %): Mixture too lean, more fuel must be injected. (Programmed basic fuel injection time too
short, actual fuel injection time - % longer, so that = 1 is obtained).
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jection
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Negative learning value ( %): Mixture too rich, less fuel must be injected. (Programmed basic fuel injection time too
long, actual fuel injection time - % shorter so that = 1 is achieved).
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jection
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01-178
Test table display group 005 and/or display group 006 Display
fields Display on
VAG 1551
scan tool Malfunction cause
Malfunction repair
1, 2, 3, 4 Low oxygen
sensor learning
values
If first learning value in display field 1 is low, but
learning value in display fields 2, 3 and 4 normal:
oil dilution (large amount of fuel in the oil), fuel
injector leaks - Pull off cylinder block breather hose
and close
- If problem disappears after drive on
expressway and/or oil change
- Check fuel injector page 24
-29
If all four oxygen sensor learning values very low
overall:
- Fuel system pressure too high
- EVAP canister purge regulator valve -N80- open
continuously - Check system and residual pressure
page 24
-20

- Check -N80- page 24
-58
and/or
display group 009, display field 3
and/or display group 001, display field
2


Mass Air Flow (MAF) sensor -G70- faulty
Oxygen sensor (O2S) heating faulty or Heated
Oxygen Sensor (HO2S) dirty - Check MAF sensor -G70 page 24
-
81

- Check HO2S and O2S heating
page 24
-49
and/or display group 010,
display fields 1 and 2
Pa
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gnostic
(OBD
) - Multi
port Fuel In
jection
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)
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