AUDI A4 1995 B5 / 1.G AFC Engine On Board Diagnostic Multiport Fuel Injection Workshop Manual

01-235
Notes on display field 3 and 4:
Value "0" = Diagnosis condition not fulfilled.
Value "1" = Diagnosis condition fulfilled. X
X
X
X
X
X
X
X
Meaning of 8-digit "Diagnosis condition 1"

1 = Coolant temperature: 70 - 110 C ( display group 001)
2 = Engine load: 27 - 66% ( display group 003)
3 = Engine speed: 1800 - 2700 RPM ( display group 003)
4 = Fuel throughput after engine start
[only fulfilled after approx. 3 min. trip (no idle) after start]

5 = No fuel enrichment
(during diagnosis no enrichment can occur display group 019)
6 = Closed throttle position switch open ( display group 008)
7 = Oxygen sensor control, bank 2 active ( display group 008)
8 = Oxygen sensor control, bank 1 active ( display group 007)
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01-236

X
X
X
X
X
X
X
X
Meaning of 8-digit "Diagnosis condition 2"

1 = Constant drive

2 = Oxygen sensor heating, bank 1 OK ( display group 040)
3 = Oxygen sensor heating, bank 2 OK ( display group 040)
4 = Vehicle speed: 80 - 100 km/h (50 to 63 mph) ( display group 003)
5 = Value does not drop below or exceed oxygen sensor control limit for bank 2 ( display
group 008)
6 = Value does not drop below or exceed oxygen sensor control limit for bank 1 ( display
group 007)

7 = Calculated exhaust gas temperature in front of three way catalytic converter: 400 - 640 C
(752 - 1184 F)
8 = Throttle angle constant ( display group 003) Re: 5 and 6: With a lot of fuel vapor on the EVAP system diagnosis, use function 04 to carry out "Basic Setting" (EVAP
system automatically shut off during function 04).
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01-237
Display group 043 [Current flank rise and/or flank fall time (response time) of voltage signal of heated oxygen
sensors in front of three way catalytic converters]
Notes:

When diagnostic conditions are fulfilled ( display group 042) display group 043 shows the current flank rise and/or flank
fall times. After diagnosis is ended, the diagnostic times shown are those that were recognized when the most recent
diagnosis was carried out. If the limit values (flank rise time 90 ms/flank fall time 85 ms) are exceeded, the diagnosis is recognized as not OK. The
flank rise and/or flank fall times now continue to be checked, while the display values in display group 034 are
incremented with each additional test. However, the limit values can also be exceeded because of combustion misfiring
being recognized. In this case, the malfunction "Bank X probe Y signal too slow" is not stored in DTC memory, but" Cyl. x
Combustion misfiring recognized" is stored.
Display shows
Display specified value
Designation/diagnosis
Basic setting 43
1 2 3 4 0.0 - 260.0 ms 1 = Flank rise time, bank 1, heated oxygen sensor 1
(limit value: 90 ms)
0.0 - 260.0 ms 2 = Flank fall time, bank 1, heated oxygen sensor 1
(limit value: 85 ms)
0.0 - 260.0 ms 3 = Flank rise time, bank 2, heated oxygen sensor 1
(limit value: 90 ms)
0.0 - 260.0 ms 4 = Flank fall time, bank 2, heated oxygen sensor 1
(limit value: 85 ms)
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01-238
Display group 044 (Diagnostic conditions for three way catalytic converter diagnosis, bank 1 and bank 2)
Notes:

When the diagnostic conditions are fulfilled (display fields 3 and 4) by using the heated oxygen sensors in front of and
behind the three way catalytic converter, at each start the Engine Control Module (ECM) carries out a diagnosis of the
three way catalytic converter. During this diagnosis, the deterioration rate of the three way catalytic converter is
determined. The deterioration rate of the three way catalytic converter is displayed when display groups 035 and 036 are
displayed. However, this diagnosis is "cross-blocked." That means that before the three way catalytic converter diagnosis
can be evaluated, a result of the heated oxygen sensor diagnosis must be available to the Engine Control Module (ECM).
If a malfunction is stored in DTC memory that affects the heated oxygen sensors in front of or behind the three way
catalytic converter, the heated oxygen sensor diagnosis can not be carried out and the three way catalytic converter
diagnosis can not be evaluated.
If in display group 029, display field 1 the value of the three way catalytic converter diagnosis is not set to "0" during
regeneration of the readiness code, and/or a malfunction is stored in DTC memory that affects the three way catalytic
converter, display group 044 can be used to selectively call the diagnostic conditions (display fields 3 and 4).
If in display group 029, display field 1 the value of the three way catalytic converter diagnosis and the value of the heated
oxygen sensor diagnosis are not set to "0" during regeneration of the readiness code, display group 044, display field 1
can be used to determine whether the three way catalytic converter diagnosis has been carried out inside the engine
control module, but the value of the three way catalytic converter diagnosis under display group 029, display field 1 can
not be set to "0" because the heated oxygen sensor diagnosis has not been carried out.
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01-239

The diagnostic conditions are only achieved during a trip of approx. 1-1/2 to 5 minutes at 80-100 km/h (50-63 mph) with
manual transmission in 4th or 5th gear, or automatic transmission selector lever in "D" position, preferably in 4th gear.
However, the diagnostic conditions are only displayed 4 minutes after engine start, because until that time diagnosis is
prohibited. If the diagnostic conditions are fulfilled, diagnosis is active. Now, obtaining a diagnostic result requires a test
drive of approx. 1-1/2 to 5 min under the diagnostic conditions.
If a malfunction is stored in DTC memory that affects diagnostic conditions 1 and 2, the diagnostic conditions can not be
obtained. In this case repair the malfunction "DTC memory, checking and erasing," page 01
-13
. If a malfunction is
stored that involves the heated oxygen sensors in front of three way catalytic converter, the diagnostic conditions can be
achieved, but the diagnosis result can not be OK.
If the effect of the three way catalytic converter is recognized as OK during the first diagnosis, the diagnosis is
discontinued. If the effect (conversion) is recognized as not OK, the three way catalytic converter diagnosis is continued. If
the diagnosis will be repeated selectively and/or repeated after an OK diagnosis, stop the engine and start again.
Display
shows Display specified
value Designation/diagnosis
Basic setting
44
1 2 3 4 X _ X _ X X X X 1 = Diagnosis status

400 - 640 C
2 = Calculated temperature in three way catalytic converter (calculated value inside
the engine control module)
X X X X X X X X 3 = Diagnostic conditions 1 for three way catalytic converter diagnosis
X X X X X X X X 4 = Diagnostic conditions 2 for three way catalytic converter diagnosis
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01-240
Notes on display field 1:
Display field 1 shows which diagnosis has been carried out or has not been carried out yet. If the three way catalytic converter
diagnosis is carried out inside the engine control module, but the heated oxygen sensor diagnosis has not been carried out
yet, the three way catalytic converter diagnosis is not evaluated and therefore the deterioration rate is not set in display
groups 035 and 036.
Value "0" = Diagnosis carried out
Value "1" = Diagnosis not carried out X

X

X
X
X
X
Meaning of 6-digit display

1 = Diagnosis flank fall time, bank 1, heated oxygen sensor 1

2 = Diagnosis flank rise time, bank 1, heated oxygen sensor 1

3 = Diagnosis flank fall time, bank 2, heated oxygen sensor 1

4 = Diagnosis flank rise time, bank 2, heated oxygen sensor 1

5 = ----------

6 = Three way catalytic converter diagnosis, bank 1

7 = ----------

8 = Three way catalytic converter diagnosis, bank 2
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01-241
Notes on display field 3 and 4:
Value "0" = Diagnosis condition not fulfilled
Value "1" = Diagnosis condition fulfilled X
X
X
X
X
X
X
X
Meaning of 8-digit display "Diagnosis condition 1"

1 = Coolant temperature: 70 - 110 C ( display group 001)
2 = Oxygen sensor heating (all four O2S heaters; display group 040)
3 = Momentary constant drive

4 = No fuel enrichment (during diagnosis no enrichment can occur)

5 = Long-term constant drive

6 = Closed throttle position switch open ( display group 002)
7 = Oxygen sensor control, bank 2 active ( display group 008)
8 = Oxygen sensor control, bank 1 active ( display group 007)
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01-242

X
X
X
X
X
X
X
X
Meaning of 8-digit display "Diagnosis Condition 2"

1 = Three way catalytic converter diagnosis, bank 2 active

2 = Engine load: 27 - 66% ( display group 003 )
3 = Engine speed: 1800 - 2700 RPM ( display group 003)
4 = Vehicle speed: 80 - 100 km/h (50 - 63 mph) ( display group 003)
5 = Three way catalytic converter diagnosis, bank 1 active

6 = Value does not drop below or exceed oxygen sensor control limit ( display group 007
and/or 008)
7 = Intake air mass through Mass Air Flow (MAF) sensor: 12 - 36 g/sec ( display group 019)

8 = Calculated exhaust gas temperature in three way catalytic converter: 400 - 640 C (752 -
1184 F)
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01-243
Display group 045
Notes:

Display group 045 is only assigned on vehicles with tank diagnosis.
Vehicles with EVAP system/tank diagnosis can be recognized by Diagnostic Pump for Fuel System -V144-.
Display shows
Display/specified value
Designation
Basic setting 45
1 2 3 4 -------- --------------------------------------
-------- --------------------------------------
-------- --------------------------------------
-------- --------------------------------------
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01-244
Display group 099 Display
shows Display/specified
value Designation/diagnosis
Basic
setting 99
1 2 3 4 ... RPM 1 = Momentary engine speed Display group 003, display field 1 ...% 2 = Momentary engine load display group 003, display field 2
... C
3 = Coolant temperature display group 001, display field 1

-Control OFF
and/or
-Control ON
4 = Oxygen sensor control OFF in "Basic Setting" function 04; Oxygen sensor control
ON in "Read Measuring Value Block" function 08
Notes on display field 4:

For defined troubleshooting, the oxygen sensor control is switched off when display group 099 is selected under "Basic
Setting" function 04, and switched on when display group 099 is selected under "Read Measuring Value Block"function
08. When leaving "Basic Setting" function 04, oxygen sensor control is automatically active again.
You can switch back and forth between "Basic Setting" function 04 and "Read Measuring Value Block" function 08 by
pressing buttons -4- and -8- on the VAG 1551 scan tool.
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