engine AUDI A4 1998 B5 / 1.G AFC Engine On Board Diagnostic Multiport Fuel Injection Workshop Manual

X
Meaning of the 1-digit display:

Value "0" = ignition on and engine not running, or, engine running and fuel tank contents less than 12 liters (3.2 gal)
Value "1" = engine running and fuel tank contents greater than 12 liters (3.2 gal)
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Display group 029 (Diagnosis status)
Notes:
OBD II regulations require a display ("Readiness Code") that indicates readiness for inspection (annual exhaust emissions
test). The readiness code display (display field 1) shows that every component and/or system that affects the exhaust, which
can lead to switching on the MIL, has been operated at least once with positive result.
The readiness code is reset and/or erased:

Every time the DTC memory is erased (both with address word 01 function 05 and with address 33 mode 4).
When the battery is disconnected.
When the engine control module is disconnected (e.g. connecting test box VAG 1598/19, replacing ECM, etc.).
To generate the readiness code, take a "mixed city and highway" drive (short test). A "mixed city and highway" drive is
understood to be 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.
The "Trip Status" display (display field 2) shows which components and/or systems have been checked since the start of the
trip. After successful diagnosis, the current display value is set to "1" whether the diagnosis was recognized as OK or not OK.
The trip-status display is reset to "0" at each start since the components and/or systems are checked at each new start. A
"trip" is understood to be 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, with preceding cold start.
The readiness code display (display field 1) shows whether the components and/or systems checked in display field 2 were
recognized as OK or not OK by the engine control module.
If the diagnosis is recognized as OK, the current display value is set to "0."
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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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01-216
Display group 030 (EVAP system diagnosis)
Notes:

Display group 030 is only considered on vehicles with sensor for EVAP canister -G172-.
If the value of the EVAP throughput 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 EVAP system, display group 030 is
used to carry out a selective diagnosis.
Since the EVAP system is automatically shut off during "Basic Setting" function 04, display group 030 can only be
evaluated using "Read Measuring Value Block" function 08.
When diagnostic conditions are fulfilled, the Engine Control Module (ECM) checks the EVAP system at each start with the
help of the sensor for EVAP canister -G172-. The pressure between the EVAP canister and EVAP canister purge
regulator valve is measured with the sensor for EVAP canister -G172-.
The diagnostic conditions are only fulfilled during 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. If
the diagnostic conditions are fulfilled, the diagnosis is active. To get the diagnosis results, you have to drive approx. 1-1/2
to 5 minutes under the diagnostic conditions, while the pressure has to be measured with closed EVAP canister purge
regulator valve. First, the pressure must be measured with the valve closed. You can get the valve to close most easily by
having a preceding deceleration fuel shut-off. If there are problems in shutting the EVAP canister purge regulator valve by
deceleration fuel shut-off, it can also be shut by running display group 030 in "Basic Setting" function 04. Then the
pressure has to be measured again in "Read Measuring Value Block" function 08 with valve fully open.
The diagnosis is recognized as OK if the EVAP system low pressure measured in display field 1 is greater than the actual
calculated EVAP system minimum low pressure in display field 2.
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If the EVAP system is recognized as OK during the first diagnosis, the diagnosis is discontinued. If the EVAP system is
recognized as not OK, the EVAP canister throughput test is continued.
If the EVAP system throughput diagnosis is to be carried out selectively and/or after a diagnosis, shut the engine off and
start again.
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01-218

X
X
X
X
X
Meaning of 5-digit "Diagnostic Status and/or Result"

1 = Diagnostic conditions during test drive (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)
Manual transmission: 8 - 45%
Automatic Transmission: 8 - 20%
Value "0" = Diagnostic conditions not fulfilled
Value "1" = Diagnostic conditions fulfilled
Engine speed: 1600 RPM - 4500 RPM ( display group 003) Intake air through Mass Air Flow (MAF) sensor: 22 g/sec - 56 g/sec ( display group 019) Throttle angle: ( display group 003)

2 = Pressure measurement w/EVAP canister purge regulator valve completely closed
Value "0" = Pressure measurement not completed yet
Value "1" = Pressure measurement completed

3 = Pressure measurement w/EVAP canister purge regulator valve completely open
Value "0" = Pressure measurement not completed yet
Value "1" = Pressure measurement completed

4 = Diagnostic status
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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)
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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
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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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