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

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"
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01-228
Note on display field 4:
Value "0" = Cylinder without combustion misfiring
Value "1" = Cylinder with combustion misfiring X
X
X
X
X
X
Meaning of 6-digit display

1 = Cylinder 1

2 = Cylinder 2

3 = Cylinder 3

4 = Cylinder 4

5 = Cylinder 5

6 = Cylinder 6
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01-229
Display group 039 (Statistical data on combustion misfiring recognition)
Notes:

Combustion misfiring recognition always occurs in relation to 1000 RPM (1000th revolution interval).
The display values are reset only be erasing DTC memory. Selected observation time periods can be defined by resetting
the display values.
Display
shows Display specified
value Designation/diagnosis
Basic setting
39
1 2 3 4 0 - 255 1 = Highest number of instances of combustion misfiring within 1000 RPM
0 - 255 2 = Number of "1000the revolution intervals" with 30 and/or more than 30 instances
of combustion misfiring
0 - 255 3 = Number of "1000th revolution intervals" with 5 and/or more than 5 instances of
combustion misfiring
X X X X X X 4 = Cylinders involved in combustion misfiring during the entire statistics period
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01-230
Note on display field 2:
The display shows the number of "1000th revolution intervals" in which 30 or more than 30 instances of combustion misfiring
were recognized.
Note on display field 3:
The display shows the number of "1000th revolution intervals" in which 5 or more than 5 instances of combustion misfiring
were recognized.
Note on display field 4:
Value "0" = Cylinder without combustion misfiring
Value "1" = Cylinder with combustion misfiring X
X
X
X
X
X
Meaning of 6-digit display

1 = Cylinder 1

2 = Cylinder 2

3 = Cylinder 3

4 = Cylinder 4

5 = Cylinder 5

6 = Cylinder 6
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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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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
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voltage less than 0.1 volts), the transition from low to high voltage can be delayed up to 10 seconds. If acceleration is
uniform after a preceding deceleration fuel shut off, the transition from low to high voltage is delayed up to 3 minutes.
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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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5 = Diagnosis result, bank 1, flank rise time

6 = Diagnosis, bank 2 finished

7 = Diagnosis result, bank 2, flank fall time

8 = Diagnosis result, bank 2, flank rise time
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