2000 AUDI A4 catalytic converter

01-212
If the trip status display is set to "1" when the readiness code is regenerated, but the corresponding display value of the
readiness code is not set to "0", the diagnosis was carried out but recognized as not OK by the engine control module. In this
case, the DTC memory should be checked to determine malfunctions and/or to carry out a selective diagnosis:

For three way catalytic converter diagnosis (Bank 1 and 2) also check display groups 035, 036 and 044.
For the Evaporative Emissions (EVAP) system leak diagnosis, also check display group 030.
For the Secondary Air Injection (AIR) system throughput and leak diagnosis, also check display groups 020 and 021.
For oxygen sensor diagnosis, also check display groups 032, 033, 034, 041, 042 and 043.
For oxygen sensor heating diagnosis, also check display group 040.
For the Exhaust Gas Recirculation (EGR) system throughput diagnosis, also check display group 017.
Display
shows Display specified
value Designation/diagnosis
Basic setting
29
1 2 3 4 X X X X X X 1 = Readiness Code
X X X X X X X X 2 = Trip Status display
0 - 40 3 = Counter for warm-up phases without new malfunctions except for "combustion
misfiring" and/or "oxygen sensor control"
0 - 40 4 = Counter for warm-up phases without new malfunctions except for "combustion
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01-213
Notes on display field 1:

All readiness code values are set to "1" by disconnecting the ECM harness connector and/or disconnecting the battery,
and every time DTC memory is erased (both with address word 01 function 05 and with address word 33 mode 4).
To regenerate the readiness code, take a drive 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 ("mixed city
and highway" trip).
Value "0" = Diagnosis carried out
Value "1" = Diagnosis not OK and/or diagnosis not carried out yet
X
X
X

X
X

X
Meaning of the 6-digit "readiness codes"

1 = Three way catalytic converter diagnosis (Banks 1 and 2)

2 = ----

3 = Evaporative Emissions (EVAP) throughput diagnosis

4 = Secondary air system throughput and leak diagnosis (Always "0" for vehicles without
secondary air injection system)

5 = ----

6 = Heated oxygen sensor diagnosis (flank rise and/or flank fall time of the voltage signal of
heated oxygen sensors in front of three way catalytic converters

7 = Oxygen sensor heating diagnosis (all four O2S heaters)

8 = Exhaust Gas Recirculation (EGR) throughput diagnosis
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01-214
Notes on display field 2:

The display values are set to "0" at each start, since the function capability of components and systems that can affect the
exhaust are checked again and again.
Leak testing of the EGR system is only carried out after a preceding cold start (water temperature -10 C to 30 C (14 to
86 F). Value "0" = Diagnosis not carried out yet
Value "1" = Diagnosis carried out
X
X
X
X
X
X
X
X
Meaning of 8-digit "Trip Status" display

1 = Three way catalytic converter diagnosis, banks 1 and 2
(for diagnostic conditions display group 044)
2 = Exhaust Gas Recirculation (EGR) system leak testing

3 = Evaporative Emissions (EVAP) throughput diagnosis
(for diagnostic conditions display group 030)
4 = Secondary air injection system throughput and leak testing
(always "0" on vehicles without secondary air injection system; for diagnostic conditions
display groups 020 and 021)
5 = Oxygen sensor control diagnosis
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(for diagnostic conditions display groups 007 and 008)

6 = Heated oxygen sensor diagnosis (flank rise and/or flank fall time of the voltage signal on
the heated oxygen sensor in front of three way catalytic converter; for diagnostic conditions
display group 042)
7 = Oxygen sensor heating diagnosis (all four O2S heaters)

8 = Exhaust Gas Recirculation (EGR) system throughput diagnosis
(for diagnostic conditions display group 017)
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01-220
Display group 032 [Longest and shortest flank rise and flank fall time (response time) of the voltage signal for bank 1
heated oxygen sensor 1]
Display group 033 [Longest and shortest flank rise and flank fall time (response time) of the voltage signal for bank 2
heated oxygen sensor 2]
Display group 034 [Number of flank rise and flank fall tests]
Notes on display group 032, 033 and 034:

If the value of the heated 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 the DTC memory that relates to the heated oxygen sensors, display
groups 032, 033 and 034, as well as display groups 042 and 043 are used to carry out a selective diagnosis.
The Engine Control Module (ECM) checks the flank rise and/or flank fall time (response time) of the voltage signal for the
heated oxygen sensors in front of three way catalytic converter after every start with diagnostic conditions fulfilled
display group 042. The display values for display group 034 are incremented with each diagnosis that is carried out, whether the diagnosis is
recognized as OK or not OK. If the flank rise and/or flank fall time is recognized as OK during the first diagnosis, the
display values are increased by the value "1" and the diagnosis is discontinued. 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 fall times now
continue to be checked, whereby the display values are incremented with each additional diagnosis. However, the limit
values can also be exceeded because combustion misfiring is 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.
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01-223
Display group 035 (Three way catalytic converter diagnosis, bank 1)
Display group 036 (Three way catalytic converter diagnosis, bank 2)
Notes on display groups 035 and 036:

If the value of the three way catalytic converter 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 three way catalytic
converter, display groups 035, 036 and 044 are used to carry out a selective diagnosis.
At each start, when the diagnostic conditions are fulfilled ( display group 044) the Engine Control Module (ECM) checks
the deterioration rate of the three way catalytic converter by the heated oxygen sensors in front of and behind the three
way catalytic converter. Display fields 1 and 2 display the largest and smallest rate of deterioration of all the diagnoses carried out. If a higher or
lower rate of deterioration is recognized at the next diagnosis, the current value is overwritten.
The number of three way catalytic converter diagnoses (display field 3) is incremented each time a diagnosis is carried
out, no matter whether the diagnosis is considered OK or not OK.
If the rate of deterioration is recognized as OK during the first diagnosis, the number of three way catalytic converter
diagnoses is increased by the value of "1" and the diagnosis is discontinued.
If the limit value of 50% is exceeded, the diagnosis is recognized as not OK. In this case, the rate of deterioration
continues to be checked, while the number of three way catalytic converter diagnoses is incremented with each additional
diagnosis.
Display field 4 shows the current rate of deterioration recognized at the last diagnosis.
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01-224

Display shows
Display specified value
Designation/diagnosis
Basic setting 35
1 2 3 4 0 - 100% 1 = Maximum deterioration rate, bank 1 (limit value: 50%)
0 - 100% 2 = Minimum deterioration rate, bank 1 (limit value: 50%)
0 - 255% 3 = Number of three way catalytic converter diagnoses, bank 1
0 - 100% 4 = Last calculated deterioration rate, bank 1 (limit value: 50%) Display shows
Display specified value
Designation/diagnosis
Basic setting 36
1 2 3 4 0 - 100% 1 = Maximum deterioration rate, bank 2 (limit value: 50%)
0 - 100% 2 = Minimum deterioration rate, bank 2 (limit value: 50%)
0 - 255 3 = Number of three way catalytic converter diagnoses, bank 2
0 - 100% 4 = Last calculated deterioration rate, bank 2 (limit value: 50%)
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01-231
Display group 040 (Heating current of oxygen sensors in front of and behind three way catalytic converter) Display
shows Display specified value
Designation/diagnosis
Basic setting
40
1 2 3 4 At cold start, greater than 3 A after approx. 40 sec: 0.7 -
1.0 A 1 = Heating current, bank 1, heated oxygen
sensor 1
2 = Heating current, bank 2, heated oxygen
sensor 1
At cold start, greater than 3 A after approx. 80 sec: 1.2 -
1.4 A 3 = Heating current, bank 1, heated oxygen
sensor 2
4 = Heating current, bank 2, heated oxygen
sensor 2 Notes:

The current values specified apply only at when battery positive voltage (B+) is 12-14 volts display group 001, display
field 4. The heating of the heated oxygen sensors in front of the three way catalytic converter is switched on with the fuel pump
relay, i.e. immediately at engine start.
The heating of the heated oxygen sensors behind the three way catalytic converter is not switched on immediately at
engine start, but only when the calculated exhaust gas temperature in the three way catalytic converter exceeds 308 C
(586 F) display group 044, display field 2. In order to reach an exhaust gas temperature of 308 C (586 F) in the three
way catalytic converter after a cold start, the car must be driven about 20 sec. with an increased engine speed of 2500
RPM.
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