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

01-6

The MFI control module differentiates among approx. 150 different malfunctions after evaluating the information, and
stores them until the DTC memory is erased Diagnostic Trouble Code (DTC) table, page 01
-26
.
If possible, the DTC memory should be checked with engine running.
If no malfunction is stored in the DTC memory, do not additionally erase DTC memory with function 05 since the readiness
code (if it has been set) will be erased.
The DTC memory should only be erased with function 05 since the DTC memory is erased immediately with mode 4 even
if the DTC memory was not checked before that.
If a malfunction recognized by the On Board Diagnostic (OBD) is eliminated, the following work steps should be carried
out after that:
- Erase DTC memory
- Stop engine (switch ignition off) and start it again
- Take a test drive
- Carry out automatic test sequence by inserting address word 00 Note:
Every time the DTC memory is erased (both with function 05 and with mode 4), the readiness code is reset.
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01-150

Basic Setting (scan tool function 04)


Notes:

Basic setting is carried out with engine
running.
The OBD II engine control module shows the
"Readiness Code" in display group 29. The
readiness code is reset when the engine control
module power is off and each time the DTC
memory is erased. In order to regenerate the
readiness code it is necessary to take a trip in
"mixed city and highway" driving-approx. 1-1/2
to 5 minute drive at 80-100 km/h (50-63 mph)
with manual transmission in 4th or 5th gear,
preferably 4th gear, or automatic transmission
selector lever in "D" position.
When the "Basic Setting" function 04 is initiated
with the VAG 1551 scan tool, the learning
values are relearned in systems capable of
learning. Learning is prohibited, as soon as a
malfunction is stored in the DTC memory that
relates to a system capable of learning (not with
sporadic malfunctions).
All learning values are erased by disconnecting
the connector from the Engine Control Module
(ECM). After that, uneven idle can occur briefly.
In this case, let engine run in idle for a few
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01-184
Notes on display field 3

The oxygen sensor learning requirement diagnosis shows what oxygen sensor learning value was checked in the learning
process.
If diagnosis is successful, the corresponding value is set to "1", independently of whether the diagnosis was recognized as
OK or not OK.
If an "oxygen sensor learning requirement diagnosis" value is set to "1" in display field 3, but the corresponding value of
the "oxygen sensor learning requirement display" is not set to "1" in display field 4, the diagnosis was carried out but not
recognized as OK by the Engine Control Module (ECM). The " oxygen sensor learning requirement diagnosis" is now
continued.
The oxygen sensor learning requirement diagnosis is reset to "0" every time there is a start with a coolant temperature
less than 40 C (104 F).
X
X
X
X
X
X
X
X
Meaning of 8-digit oxygen sensor learning requirement diagnosis

1 = Idle (bank 1)

2 = Idle (bank 2)

3 = Partial throttle 1 (bank 1)

4 = Partial throttle 1 (bank 2)

5 = Partial throttle 2 (bank 1)

6 = Partial throttle 2 (bank 2)

7 = Partial throttle 3 (bank 1)
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During "Basic Setting" function 04 with VAG 1551 scan tool and/or each time the DTC memory is erased, all learning
requirement displays are set to 0 in order to force new learning of the oxygen sensor learning values after the shop visit.
At each start, coolant temperature less than 40 C (104 F), the learning requirement is forced in all learning ranges. If there is a large learning value deviation (from the stored learning value to the newly learned value) in the learning
process, all learning requirement displays are reset to 0.
If there is successful learning, the learning requirement values of the respective learning ranges (display field 2) are set to 1.
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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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If the diagnosis is recognized as not OK, the current display value is not set to "0", it stays at "1."
If every component and/or system has operated at least once with positive results, all display values of the readiness code
are set to "0."
If, during another diagnosis, a component and/or system is recognized as not OK, the readiness code is not reset to "1."
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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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The display values are only reset by erasing the DTC memory. Selective observation time periods can be defined by
resetting the display values.
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01-229
Display group 039 (Statistical data on combustion misfiring recognition)
Notes:

Combustion misfiring recognition always occurs in relation to 1000 RPM (1000th revolution interval).
The display values are reset only be erasing DTC memory. Selected observation time periods can be defined by resetting
the display values.
Display
shows Display specified
value Designation/diagnosis
Basic setting
39
1 2 3 4 0 - 255 1 = Highest number of instances of combustion misfiring within 1000 RPM
0 - 255 2 = Number of "1000the revolution intervals" with 30 and/or more than 30 instances
of combustion misfiring
0 - 255 3 = Number of "1000th revolution intervals" with 5 and/or more than 5 instances of
combustion misfiring
X X X X X X 4 = Cylinders involved in combustion misfiring during the entire statistics period
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01-234

Display
shows Display specified
value Designation/diagnosis
Basic setting
42
1 2 3 4 400 - 640 C
1 = Calculated exhaust gas temperature in front of three way catalytic converter
(calculated value inside control module)
X X X X X X X X 2 = Diagnosis status and/or result
X X X X X X X X 3 = Diagnostic conditions 1 for heated oxygen sensor diagnosis (response time of
heated oxygen sensor)
X X X X X X X X 4 = Diagnostic conditions 2 for heated oxygen sensor diagnosis (response time of
heated oxygen sensor)
Note on display field 2:
If after diagnosis all 8 displays are "1" and the engine is stopped and started again, display values 1 and 2 are reset to "0" and
values 3 to 8 remain at "1." If during the trip diagnostic conditions (display fields 3 and 4) are achieved, display values 1 and 2
are set to "1" (diagnosis active) and display values 3 to 8 are set to"0".
Value "0": Diagnosis not active and/or diagnosis not finished and/or diagnosis result not OK
Value "1": Diagnosis active and/or diagnosis finished (whether OK or not OK) and/or diagnosis result OK X
X
X
X
X
X
X
X
Meaning of 8-digit "Diagnosis status and/or result"

1 = Diagnosis, bank 1 active

2 = Diagnosis, bank 2 active

3 = Diagnosis, bank 1 finished

4 = Diagnosis result, bank 1, flank fall time
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