display AUDI A4 1996 B5 / 1.G AFC Engine On Board Diagnostic Multiport Fuel Injection Workshop Manual

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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01-215
Notes on display fields 3 and 4:

Display field 3 evaluates all malfunctions except "Combustion misfiring and oxygen sensor control."
Display field 4 evaluates only the malfunctions "Combustion misfiring and oxygen sensor control"
If a malfunction is recognized, the corresponding counter will be set to "40." The counter is decremented, during a new
start, when the trip was started at coolant temperature of 49 C (120 F) and ended at a water temperature of 71 C
(160 F) and the malfunction is no longer recognized. However, decrementing is only allowed if the MIL has not lit up yet
or is no longer lit. When counter status "0" is reached, the recognized malfunction is erased. If the DTC memory is erased, the counter is also decremented.
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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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01-217

Display shows
Display/specified value
Designation/diagnosis
Basic setting 30
1 2 3 4 -- mbar 1 = Currently measured EVAP system under pressure
-- mbar 2 = Currently calculated EVAP minimum under pressure
0 - 99% 3 = Duty cycle (triggering) EVAP canister purge regulator valve
0% = completely open
99% = completely closed
X X X X X 4 = Diagnosis status and/or result Note on display field 2:
An under pressure calculated from the momentary throughput of the Mass Air Flow (MAF) sensor (intake air mass) is
displayed.
Notes on display field 4:
0 1 X X X = Diagnosis carried out, diagnosis OK
1 0 X X X = Diagnosis carried out, malfunction recognized, diagnosis is continued
The display positions marked with X do not have to be fulfilled to evaluate the diagnostic status and/or result.
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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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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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01-221

Display groups 032 and 033 show the highest and lowest flank rise and/or flank fall time for all tests carried out (number of
tests display group 034). If during one of the next tests, a higher or lower diagnosis time is recognized, the current value is overwritten. With
diagnostic conditions fulfilled, display group 043 shows the current flank rise and flank fall times. After diagnosis is ended,
the diagnosis times shown are those that were recognized at the last diagnosis that was carried out.
The display values are only reset by erasing the DTC memory. Selective observation times can be defined by resetting the
display values.
Display shows
Display specified value
Designation/diagnosis
Basic setting 32
1 2 3 4 0.0 - 260.0 ms 1 = Highest flank rise time, bank 1, heated oxygen sensor 1
(limit value: 90 ms)
0.0 - 260.0 ms 2 = Lowest flank rise time, bank 1, heated oxygen sensor 1
(limit value: 90 ms)
0.0 - 260.0 ms 3 = Highest flank fall time, bank 1, heated oxygen sensor 1
(limit value: 100 ms)
0.0 - 260.0 ms 4 = Lowest flank fall time, bank 1, heated oxygen sensor 1
(limit value: 100 ms)
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01-222

Display shows
Display specified value
Designation/diagnosis
Basic setting 33
1 2 3 4 0.0 - 260.0 ms 1 = Highest flank rise time, bank 2, heated oxygen sensor 1
(limit value: 90 ms)
0.0 - 260.0 ms 2 = Lowest flank rise time, bank 2, heated oxygen sensor 1
(limit value: 90 ms)
0.0 - 260.0 ms 3 = Highest flank fall time, bank 2, heated oxygen sensor 1
(limit value: 100 ms)
0.0 - 260.0 ms 4 = Lowest flank fall time, bank 2, heated oxygen sensor 1
(limit value: 100 ms) Display shows
Display specified value
Designation/diagnosis
Basic setting 34
1 2 3 4 0 - 255 1 = Number of flank rise tests, bank 1, heated oxygen sensor 1
0 - 255 2 = Number of flank fall tests, bank 1, heated oxygen sensor 1
0 - 255 3 = Number of flank rise tests, bank 2, heated oxygen sensor 1
0 - 255 4 = Number of flank fall tests, bank 2, heated oxygen sensor 1
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