1996 AUDI A4 AFC Engine On Board Diagnostic Multiport Fuel Injection Workshop Manual

(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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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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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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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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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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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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