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

01-198
Display groups 015 and 016
Notes on display fields 2, 3 and 4:
If there is a difference of more than a factor of 3 between the lowest and the highest knock sensor signal in one display group,
the following malfunction is possible:

Corrosion on the harness connector
If there are differences of more than 50% in knock sensor signal between display group 015 (cylinders 1 to 3) and display
group 016 (cylinders 4 to 6), the following malfunctions are possible:
Corrosion on the harness connector
Open circuit
Knock sensor faulty
If no malfunctions are found during the electrical testing of the knock sensor, the wiring and the connections, the engine
should be checked for loose subassemblies or engine damage (e.g. oil burning due to faulty piston) Display groups 013
and/or 014.
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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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01-207
Note on display field 3: X
X
Meaning of the 2-digit display:

1 = A/C compressor off/on (0 = off; 1 = on)
Notes:

On vehicles without A/C "0" is always displayed.
Check A/C compressor page 24
-90
.
The A/C compressor is shut off for approx. 12 sec. by -J192- when accelerating from a stop and from low speed.
If the gas pedal is released sooner, the time is reduced to a minimum of 3 sec. At wide open throttle, the A/C
compressor is switched off by the automatic transmission (kick-down switch).

2 = Rear window heating - Signal (0 = off; 1 = on)
Notes:
The rear window heating signal is only displayed on vehicles without A/C.
On vehicles with A/C "0" is always displayed.
Check rear window heater signal page 24
-88
.
Notes on display field 4:

If the A/C compressor is off display field 3; display field 4 can be used to recognize whether the compressor was
switched off by the engine control module. Meaning of the 1-digit display:
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01-209
Display group 027 Display
shows Display specified
value Designation/diagnosis
Basic setting
27
1 2 3 4 X 1 = Malfunction Indicator Lamp (MIL) wire from Transmission Control Module
(TCM)
X 2 = Fuel level signal from instrument cluster
0.000 V 3 = ---------------
0.000 V 4 = --------------- Notes on display field 1:

On vehicles with manual transmission, "1" is always displayed.
Checking Malfunction Indicator Lamp (MIL) wire from transmission control module page 24
-105
.
X
Meaning of the 1-digit display:

Value "0" = ignition on, engine not running
Value "1" = engine running Note on display field 2:

Check fuel level signal from instrument cluster page 24
-107
.
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01-211
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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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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