lock AUDI A4 2000 B5 / 1.G AFC Engine On Board Diagnostic Multiport Fuel Injection User Guide

01-151

Note:
After function 04 is called up, the Engine Control
Module (ECM) carries out the following
operations:

Constant ignition timing point of 12 BTDC is
output in idle.

Digital idle speed control is blocked.
Evaporative emissions canister purge regulator
valve is closed.
A/C compressor is switched off.
EGR vacuum regulator solenoid valve is
closed
No coolant temperature correction-fixed value
of 80 C (176 F)

Learning values are relearned (idle and CO
content are adjusted automatically)
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01-167
Notes on display field 1:

The Engine Coolant Temperature (ECT) sensor is a temperature-dependent resistor. If the sensor signal is falsified by e.g.
dampness in the harness connection (effect as with resistors connected in parallel), this falsification can lie in a range that
is not recognized by the DTC memory.
If a malfunction relating to the Engine Coolant Temperature (ECT) sensor is stored, a coolant temperature of 20 C (68
F) is displayed in the measuring block at engine start. 10 C (50 F) is added to this for each minute of engine operation.
The maximum replacement value is 85 C (185 F).
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01-178
Test table display group 005 and/or display group 006 Display
fields Display on
VAG 1551
scan tool Malfunction cause
Malfunction repair
1, 2, 3, 4 Low oxygen
sensor learning
values
If first learning value in display field 1 is low, but
learning value in display fields 2, 3 and 4 normal:
oil dilution (large amount of fuel in the oil), fuel
injector leaks - Pull off cylinder block breather hose
and close
- If problem disappears after drive on
expressway and/or oil change
- Check fuel injector page 24
-29
If all four oxygen sensor learning values very low
overall:
- Fuel system pressure too high
- EVAP canister purge regulator valve -N80- open
continuously - Check system and residual pressure
page 24
-20

- Check -N80- page 24
-58
and/or
display group 009, display field 3
and/or display group 001, display field
2


Mass Air Flow (MAF) sensor -G70- faulty
Oxygen sensor (O2S) heating faulty or Heated
Oxygen Sensor (HO2S) dirty - Check MAF sensor -G70 page 24
-
81

- Check HO2S and O2S heating
page 24
-49
and/or display group 010,
display fields 1 and 2
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01-181
Display group 007 Display shows
Display/specified value
Designation/diagnose
Basic setting 7
1 2 3 4 0.0 6.0%1)
1 = Oxygen sensor (O2S) control (bank 1)

XXXX 2 = Oxygen sensor learning range display

XXXXXXXX 3 = Oxygen sensor learning requirement diagnosis

XXXXXXXX 4 = Oxygen sensor learning requirement display
Display group 008 Display shows
Display/specified value
Designation/diagnose
Basic setting 8
1 2 3 4 0.0 6.0%1)
1 = Oxygen sensor (O2S) control (bank 2)

XXXX 2 = Oxygen sensor learning range display

XXXXXXXX 3 = Oxygen sensor learning requirement diagnosis

XXXXXXXX 4 = Oxygen sensor learning requirement display
1) Evaluate tolerance range of the oxygen sensor control only at idle during "Basic Setting" function 04, since the EVAP
canister can also be controlled during "Read Measuring Value Block" function 08
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Oxygen sensor control can basically be evaluated both in "Basic Setting" function 04 as well as in "Read Measuring Value
Block" function 08 only after successful learning ( learning requirement display). Oxygen sensor control shows momentary control status. After successful learning, ( learning requirement display),
values vary around 0.0 6.0%. If the learning process (display field 4) is ended and no value around 0.0 6.0% is
obtained, observe display group 010, display fields 3 and/or 4 and check control behavior of the two heated oxygen
sensors. During this process, the display values must at times drop below 0.3 V and exceed 0.6 V, otherwise check
oxygen sensor heating and the heated oxygen sensor.
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01-187
Display group 009 Display shows
Specified display value
Designation
Basic setting 9
1 2 3 4 ... % 1 = Oxygen sensor control (bank 1)
... % 2 = Oxygen sensor control (bank 2)
0 - 99% 3 = Duty cycle (triggering)-EVAP canister purge regulator valve -N80-
0% and/or greater than 95% 4 = Throttle angle - at idle: 0%; at wide open throttle: > 95% Note:
The oxygen sensor control should always be evaluated only after successful learning ( learning requirement display, display
group 007 and/or 008, display field 4) in both "Basic Setting" function 04 and "Read Measuring Value Block" function 08.
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01-188
Test table display group 009 Display fields
Display on VAG 1551 scan tool
Malfunction cause
Malfunction repair
1 -
- Display group 007, display field 1
2 -
- Display group 008, display field 13 -
- Note4 -
- Display group 003, display field 3
Notes on display field 3:

The evaporative emissions valve (EVAP canister valve) is closed during the learning process.
The effect of the EVAP canister can be evaluated by comparing the display value during "Basic setting" (EVAP canister
completely closed: 99%) and during "Read Measuring Value Block" (EVAP canister valve completely open: 0%).
You can switch back and forth between "Basic Setting" function 04 and "Read Measuring Value Block" function 08 by
pressing buttons -1- and -3- on VAG 1551 scan tool.
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Notes on display field 3:

Digital idle speed control (ISC) is only active with the Closed Throttle Position (CTP) switch closed.
Ignition timing point access to digital ISC with open CTP switch: 0.0 crankshaft. During "Basic Setting" function 04, digital ISC is blocked, display shows 0.0 crankshaft. Ignition timing point access to DLS during "Read Measuring Value Block" function 08 at idle without electrical consumers:
0.0 3.0 crankshaft.
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If there is engine damage (oil burning because of faulty piston)
If a knock sensor malfunction is recognized in DTC memory, ignition map switching is blocked.
Notes on display field 4:
Knock control is active starting at an engine load greater than 40% Display groups 013 and/or 014. The ignition timing point retarding values are only used when knock control is "active."
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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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