1999 AUDI A4 engine

Value "0" = Diagnosis not carried out yet and/or diagnosis continued (with EVAP canister malfunction
recognized)
Value "1" = Diagnosis carried out (no further diagnosis until engine stop)

5 = Diagnosis result
Value "0" = Diagnosis OK
Value "1" = Diagnosis not OK (EVAP canister malfunction recognized)
Pa
ge 311 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-219
Display group 031 (Operating conditions when combustion misfiring is recognized):
Notes:

If the malfunction "Combustion misfiring recognized" and "Cyl. X Combustion misfiring recognized" are stored in DTC
memory, display groups 031, 037, 038 and 039 are used to carry out a selective diagnosis.
Display group 031 shows the operating conditions that are present at the moment the malfunction is recognized. However,
the operating conditions are only displayed if combustion misfiring is recognized by the Engine Control Module (ECM) and
stored in DTC memory. If there is more combustion misfiring that has to be displayed, the operating conditions of the most
recently recognized combustion misfiring is displayed.
If the malfunction "Combustion misfiring" is stored in the DTC memory, at the same time a counter is set to the value of
"40". This counter is displayed under display field 4 when display group 029 is called. If combustion misfiring is no longer
recognized during the next 40 warm-up phases, the malfunctions in DTC memory and the operating conditions are
erased.
Display shows
Display specified value
Designation/diagnosis
Basic setting 31
1 2 3 4 ... RPM 1 = Lowest engine speed at which combustion misfiring was recognized
... RPM 2 = Highest engine speed at which combustion misfiring was recognized
__._% 3 = Lowest engine load at which combustion misfiring was recognized
__._% 4 = Highest engine load at which combustion misfiring was recognized
Pa
ge 312 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

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.
Pa
ge 313 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

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.
Pa
ge 316 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-225
Display group 037 (Sensor wheel learning value)
Notes:

In order to be able to monitor and/or record combustion misfiring, a sensor wheel is necessary. The flywheel (starter ring
gear) is used as the sensor wheel. The flywheel is checked for mechanical damage after each start, i.e. specified
tolerances must not be exceeded.
Small malfunctions in the flywheel (e.g. teeth worn) are compensated by learning values. If greater damage is recognized,
the malfunction "engine speed sensor wheel tooth error recognized" is stored in the DTC memory.
The sensor wheel is tested during a deceleration fuel shut-off in the engine speed range from 2200 -4000 RPM. In order to
get a result, the length of the deceleration fuel shut off must be approx. 10 sec.
Display shows
Display specified value
Designation/diagnosis
Basic setting 37
1 2 3 4 X X 1 = Sensor wheel condition and/or result
______ 2 = ________________________
______ 3 = ________________________
______ 4 = ________________________
Pa
ge 319 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-227
Display group 038 (Current data on combustion misfiring recognition)
Notes:

If the malfunctions "Combustion misfiring recognized" and "Cyl. X Combustion misfiring recognized"are stored in DTC
memory, display groups 031, 037, 038 and 039 are used to carry out a selective diagnosis.
Using display group 038, after a repair you can drive again in the load and engine speed range that was displayed in
display group 031 as the combustion misfiring range and evaluated again.
Display shows
Display/specified value
Designation/diagnosis
Basic setting 38
1 2 3 4 ... RPM 1 = Momentary engine speed
__._% 2 = Momentary engine load
0 - 255 3 = Combustion misfiring per 1000 RPM (1000th revolution interval)
X X X X X X 4 = Combustion misfiring including in this "1000th revolution interval"
Pa
ge 321 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

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.
Pa
ge 325 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-232
Display group 041 (Voltage signal of oxygen sensors in front of and behind three way catalytic converter) Display
shows Display specified
value Designation/diagnosis
Basic setting
41
1 2 3 4 _.___ V 1 = Voltage signal, bank 1, heated oxygen sensor 1 display group 010, display
field 3 _.___ V 2 = Voltage signal, bank 2, heated oxygen sensor 1 display group 010, display
field 4 _.___ V 3 = Voltage signal, bank 1, heated oxygen sensor 2
_.___ V 4 = Voltage signal, bank 2, heated oxygen sensor 2 Notes on display field 3 and 4:

The voltage signals of bank 1 heated oxygen sensor 2 and/or bank 2 heated oxygen sensor 2 should not be evaluated
until at least 50 sec. after the oxygen sensor heating is switched on display group 040. With cold engine and ignition on, a voltage signal of 0.400 volts is displayed in all four display fields. With very hot engine
and ignition on, a signal of 0.000 volts is displayed in display field 3 and 4.
The voltage signal of the heated oxygen sensors behind the three way catalytic converter must lie between about 0.5 volts
and 0.6 volts with a three way catalytic converter with sufficient effect (conversion). During deceleration fuel shut off, the
voltage signal must be less than 0.1 volts constantly. During operation with wide open throttle enrichment, the voltage
signal must be greater than 0.6 volts.
If there is wide open throttle (signal voltage during wide open throttle enrichment greater than 0.6 volts) with a new three
way catalytic converter, distance driven less than 5,000 km (3,000 mi.) after a preceding deceleration fuel shut off (signal
Pa
ge 326 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1