check engine AUDI A4 1999 B5 / 1.G AFC Engine On Board Diagnostic Multiport Fuel Injection Workshop Manual

01-225
Display group 037 (Sensor wheel learning value)
Notes:

In order to be able to monitor and/or record combustion misfiring, a sensor wheel is necessary. The flywheel (starter ring
gear) is used as the sensor wheel. The flywheel is checked for mechanical damage after each start, i.e. specified
tolerances must not be exceeded.
Small malfunctions in the flywheel (e.g. teeth worn) are compensated by learning values. If greater damage is recognized,
the malfunction "engine speed sensor wheel tooth error recognized" is stored in the DTC memory.
The sensor wheel is tested during a deceleration fuel shut-off in the engine speed range from 2200 -4000 RPM. In order to
get a result, the length of the deceleration fuel shut off must be approx. 10 sec.
Display shows
Display specified value
Designation/diagnosis
Basic setting 37
1 2 3 4 X X 1 = Sensor wheel condition and/or result
______ 2 = ________________________
______ 3 = ________________________
______ 4 = ________________________
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01-233
Display group 042 [Diagnostic conditions for diagnosis of the flank rise and/or flank fall time (response time) of the
voltage signal of heated oxygen sensors in front of three way catalytic converters]
Notes:

If the value of the 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 DTC memory that relates to the oxygen sensor, display group 042 can be
used to set up the diagnostic conditions (display fields 3 and 4) and the diagnostic result (display field 2) can be read.
If the diagnostic conditions are fulfilled, the Engine Control Module (ECM) checks the flank rise and/or flank fall time
(response time) of the voltage signal of the heated oxygen sensors in front of the three way catalytic converters at each
start, which is displayed each time display groups 032, 033, 034 and 43 are displayed.
The diagnostic conditions are only fulfilled during a trip 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, diagnosis is active. In order to get a diagnosis result, you have to drive approx. 1-1/2
to 5 minutes under diagnostic conditions.
If a malfunction is stored in DTC memory, which affects diagnostic conditions 1 and 2, the diagnostic conditions can not be
achieved. In this case repair the malfunction "DTC memory, checking and erasing page 01
-13
.
If a malfunction is stored that involves the heated oxygen sensors in front of three way catalytic converters, the diagnostic
conditions can be achieved, but the diagnosis result can not be OK.
If the flank rise and flank fall time is recognized as OK during the first diagnosis, the diagnosis is discontinued. If the times
are recognized as not OK, the diagnosis of the flank rise and/or flank fall time is continued. If the diagnosis will be
repeated selectively or after an OK diagnosis, switch engine off and restart.
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01-239

The diagnostic conditions are only achieved during a trip 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.
However, the diagnostic conditions are only displayed 4 minutes after engine start, because until that time diagnosis is
prohibited. If the diagnostic conditions are fulfilled, diagnosis is active. Now, obtaining a diagnostic result requires a test
drive of approx. 1-1/2 to 5 min under the diagnostic conditions.
If a malfunction is stored in DTC memory that affects diagnostic conditions 1 and 2, the diagnostic conditions can not be
obtained. In this case repair the malfunction "DTC memory, checking and erasing," page 01
-13
. If a malfunction is
stored that involves the heated oxygen sensors in front of three way catalytic converter, the diagnostic conditions can be
achieved, but the diagnosis result can not be OK.
If the effect of the three way catalytic converter is recognized as OK during the first diagnosis, the diagnosis is
discontinued. If the effect (conversion) is recognized as not OK, the three way catalytic converter diagnosis is continued. If
the diagnosis will be repeated selectively and/or repeated after an OK diagnosis, stop the engine and start again.
Display
shows Display specified
value Designation/diagnosis
Basic setting
44
1 2 3 4 X _ X _ X X X X 1 = Diagnosis status

400 - 640 C
2 = Calculated temperature in three way catalytic converter (calculated value inside
the engine control module)
X X X X X X X X 3 = Diagnostic conditions 1 for three way catalytic converter diagnosis
X X X X X X X X 4 = Diagnostic conditions 2 for three way catalytic converter diagnosis
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01-258

Generating readiness code

Notes:

In order to generate the readiness code, a
"mixed city and highway" drive (short test) has
to be taken. A "mixed city and highway" drive is
understood as 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 a malfunction is recognized and stored by the
engine control module during a "mixed city and
highway" trip, and/or the Malfunction Indicator
Lamp (MIL) is switched on, the brief test can be
interrupted by the technician and the
malfunction repaired according to the diagnostic
trouble code.
If the readiness code has to be generated, the
DTC memory should be checked (no faults
should be stored) and erased (readiness code
will be reset) before taking the "mixed city and
highway" trip.
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01-259

Step 1: Preparation

- Start engine and let idle.

- Connect VAG 1551 or VAG 1552 scan tool,
switch on printer and select address word 01 (
page 01
-7 )

- Check and erase DTC memory ( page 01
-
13
).

No malfunctions may be stored. If necessary:

- Repair malfunctions.

- Erase DTC memory.

- Stop engine and start again.

- Test drive and, as a check, check and erase
DTC memory again.

- After checking and erasing DTC memory, let
engine run at idle again.
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