1999 AUDI A4 air condition

01-161

Display
group Display
shows Designation
036 Basic
setting 36
1 2 3 4 Three way catalytic convertor diagnosis, bank 2
037 Basic
setting 37
1 2 3 4 Sensor wheel learning value
038 Basic
setting 38
1 2 3 4 Current data on combustion misfiring recognition
039 Basic
setting 39
1 2 3 4 Statistical data on combustion misfiring recognition
040 Basic
setting 40
1 2 3 4 Heating current of heated oxygen sensors in front of and behind three way catalytic convertors
041 Basic
setting 41
1 2 3 4 Voltage signals of heated oxygen sensors in front of and behind three way catalytic convertor
042 Basic
setting 42 Diagnostic conditions for diagnosing the flank rise and flank fall time (response time) of the
voltage signals of the heated oxygen sensors in front of three way catalytic convertors
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1 2 3 4
043 Basic
setting 43
1 2 3 4 Current flank rise and flank fall time (response time) of the voltage signals of the heated oxygen
sensors in front of three way catalytic convertors
044 Basic
setting 44
1 2 3 4 Conditions for three way catalytic convertor diagnosis (bank 1 and bank 2)
045 Basic
setting 45
1 2 3 4 Evaporative emissions (EVAP) system/tank diagnosis (only on vehicles with diagnosis pump for
fuel system -V144-)
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01-192

Display
fields Display on VAG 1551 scan tool
Malfunction cause
Malfunction repair
3/4
Constant value between 0.350 -
0.450 V Open circuit in:
Heated Oxygen Sensor (HO2S) -G39-
wiring Engine Control Module (ECM) -J192-- Check -G39- page
24
-49


Constant 0.000 V Short to ground in:
Heated Oxygen Sensor (HO2S) -G39-
wiring Engine Control Module (ECM) -J192-- Check -G39- page
24
-49


Notes on display field 4:
The display value at times must drop below 0.3 V
and exceed 0.6 V. Display values less than 0.40
V indicate lean condition; greater than 0.40 V
indicate rich condition.

HO2S voltage U (mV) vs. Lambda ( ) A - HO2S voltage (mV) high
Rich mixture (fuel excess or lack of air)
High CO value
B - Oxygen sensor probes voltage (mV) low
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01-199
Display group 017
Note:
If in display group 029, display field 1, the value of the EGR system throughput diagnosis is not set to "0" during the
regeneration of the "readiness code," and/or a malfunction relating to the exhaust system is stored in the DTC memory,
display group 017 is used to carry out a selective diagnosis.
During cold start at idle, -10 C to 30 C (14 to 86 F), and during "Basic Setting" function 04, no exhaust gas recirculation
takes place. Since exhaust gas recirculation is switched off automatically during "Basic Setting" function 04, diagnosis of EGR
throughput is evaluated only in "Read Measuring Value Block." function 08. If diagnostic conditions are fulfilled, the Engine Control Module (ECM) checks the flow through the EGR system after each
start. The diagnostic conditions are only reached during a trip at 80-100 km/h (50-63 mph) in 4th or 5 gear and/or with selector
lever in the "D"position, preferably in 4th gear position. If the diagnostic conditions are fulfilled, the diagnosis is active. In order
to get a diagnostic result, the vehicle must be driven approx. 1-1/2 to 5 minutes under the diagnostic conditions. However, the
diagnosis is only considered OK when the EGR temperature (display field 4) is greater than 50 C (122 F) during the reading
time (display field 2). Diagnosis of the EGR flow (exhaust gas recirculation quantity) is active as soon as the following diagnostic conditions are
fulfilled:

Coolant temperature: greater than 8 C (46 F) ( display group 001) Vehicle speed: constant drive
Engine speed: 2000-3000 RPM ( display group 003) Engine load: 30-60%
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01-200

Display shows
Specified display value
Designation
Basic setting 17
1 2 3 4 0 - 1 1 = Timer 1 (final value = 1)
0 - 225 2 = Timer 2 (final value = 48 or 160)
30% - 60% 3 = Momentary engine load

0C - 255C
4 = Exhaust gas recirculation temperature (EGR temperature sensor -G98-)
Notes on display fields 1 and 2:

In display fields 1 and 2, the timers are displayed. The final value of timer 2 is "48" or "160". The final values "48" and
"160" are reading times ("48" = reading time 1; "160" = reading time 2).
If the diagnostic conditions are fulfilled, the timers are incremented, outside the diagnostic conditions they are
decremented.
Counter 1 is incremented by "1" as soon as counter 2 reaches the value "255." If the value 255 is reached, counter 2 goes
back to "0" and starts to increment again up to "48" (reading time 1).
If reading time 1 has been reached, the Engine Control Module (ECM) -J192- checks the EGR temperature (display field
4). If the EGR temperature is greater than 50 C (122 F), the diagnosis is OK and the diagnostic program is discontinued.
If the EGR temperature during reading time 1 is less than 50 C (122 F),counter 2 counts up to "160"(reading time 2). When reading time 2 is reached, the -J192- checks the EGR temperature (display field 4) again. If the EGR temperature is
now greater than 50 C (122 F), the diagnosis is OK and the diagnostic program will be discontinued. If the EGR
temperature is again less than 50 C (122 F), the EGR flow test is carried out again.
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01-202
Display group 019 Display shows
Specified display value
Designation/diagnose
Basic setting 19
1 2 3 4 At idle: 1.5 - 3.5% 1 = Momentary engine power (internal computation value)
At 2500 RPM:
6.5 - 9.5%
At idle:
3.0 - 5.5 g/s 2 = Intake air quantity (via mass air flow sensor)
At 2500 RPM:
9.5 - 13.5 g/s
___ km/h 3 = Momentary vehicle speed display group 003, display field 4 _._ m/s 4 = Fuel injection time (average of all cylinders) Note on display field 1:
The momentary engine power is a control module-internal calculated value that is calculated from the amount of air taken in
under normal conditions (air pressure 1013 mbar, air temperature 20 C or 68 F).
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01-203
Display groups 020 and 021
Note:
Display groups 020 and 021 are only considered in vehicles with Secondary Air Injection (AIR) system. Display shows
Display/specified value
Designation/diagnose
Basic setting 20
1 2 3 4 0% 1 = Lean time of bank 1, HO2S 1 voltage signal
0% 2 = Lean time of bank 2, HO2S 1 voltage signal
69% 3 = Diagnosis limit value
00000000 4 = Diagnosis condition and/or result Display group 021 Display shows
Display/specified value
Designation/diagnose
Basic setting 21
1 2 3 4 0.0% 1 = Oxygen sensor control, bank 1 richens
0.0% 1 = Oxygen sensor control, bank 2 richens
14.0% 3 = Diagnosis limit value
00000000 4 = Diagnosis condition and/or result
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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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