1997 AUDI A4 engine

01-233
Display group 042 [Diagnostic conditions for diagnosis of the flank rise and/or flank fall time (response time) of the
voltage signal of heated oxygen sensors in front of three way catalytic converters]
Notes:

If the value of the oxygen sensor diagnosis is not set to "0" in display group 029, display field 1 during regeneration of the
readiness code and/or there is a malfunction in DTC memory that relates to the oxygen sensor, display group 042 can be
used to set up the diagnostic conditions (display fields 3 and 4) and the diagnostic result (display field 2) can be read.
If the diagnostic conditions are fulfilled, the Engine Control Module (ECM) checks the flank rise and/or flank fall time
(response time) of the voltage signal of the heated oxygen sensors in front of the three way catalytic converters at each
start, which is displayed each time display groups 032, 033, 034 and 43 are displayed.
The diagnostic conditions are only fulfilled 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. If
the diagnostic conditions are fulfilled, diagnosis is active. In order to get a diagnosis result, you have to drive approx. 1-1/2
to 5 minutes under diagnostic conditions.
If a malfunction is stored in DTC memory, which affects diagnostic conditions 1 and 2, the diagnostic conditions can not be
achieved. 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 converters, the diagnostic
conditions can be achieved, but the diagnosis result can not be OK.
If the flank rise and flank fall time is recognized as OK during the first diagnosis, the diagnosis is discontinued. If the times
are recognized as not OK, the diagnosis of the flank rise and/or flank fall time is continued. If the diagnosis will be
repeated selectively or after an OK diagnosis, switch engine off and restart.
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01-234

Display
shows Display specified
value Designation/diagnosis
Basic setting
42
1 2 3 4 400 - 640 C
1 = Calculated exhaust gas temperature in front of three way catalytic converter
(calculated value inside control module)
X X X X X X X X 2 = Diagnosis status and/or result
X X X X X X X X 3 = Diagnostic conditions 1 for heated oxygen sensor diagnosis (response time of
heated oxygen sensor)
X X X X X X X X 4 = Diagnostic conditions 2 for heated oxygen sensor diagnosis (response time of
heated oxygen sensor)
Note on display field 2:
If after diagnosis all 8 displays are "1" and the engine is stopped and started again, display values 1 and 2 are reset to "0" and
values 3 to 8 remain at "1." If during the trip diagnostic conditions (display fields 3 and 4) are achieved, display values 1 and 2
are set to "1" (diagnosis active) and display values 3 to 8 are set to"0".
Value "0": Diagnosis not active and/or diagnosis not finished and/or diagnosis result not OK
Value "1": Diagnosis active and/or diagnosis finished (whether OK or not OK) and/or diagnosis result OK X
X
X
X
X
X
X
X
Meaning of 8-digit "Diagnosis status and/or result"

1 = Diagnosis, bank 1 active

2 = Diagnosis, bank 2 active

3 = Diagnosis, bank 1 finished

4 = Diagnosis result, bank 1, flank fall time
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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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01-238
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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01-242

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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01-244
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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