display AUDI A4 2000 B5 / 1.G AFC Engine On Board Diagnostic Multiport Fuel Injection Workshop Manual

01-190
Test table display group 010 Display
fields Display on VAG 1551 scan tool
Malfunction cause
Malfunction repair
1/2 Difference between display value
1 (bank 1) and display value 2
(bank 2) greater than 8%
Spark plug faultyIntake air leak on one side Fuel injectors faulty - Repair cause
- Check DTC memory page 01
-13

and/or check fuel injectors page 24-
29


Heated Oxygen Sensor
(HO2S) faulty (dirty) - Check DTC memory page 01
-13

and/or display fields 3 and 4

Mechanical engine basic
setting (valve/camshaft
timing) not OK
Repair Manual, 2.8 Liter V6 2V
Engine Mechanical, Engine Code(s): AFC, Repair Group 13
- Check valve/camshaft timing
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01-191

Display
fields Display on VAG 1551 scan tool
Malfunction cause
Malfunction repair
3/4 Display does not fluctuate-constant
between 0.0 - 0.3 V and/or between
0.6 - 0.9 V
Fuel injector faulty- Check fuel injectors page 24
-29

Spark plug faultyLarge intake air leak Engine Coolant Temperature
(ECT) sensor -G62- faulty EVAP canister purge
regulator valve -N80- - Check spark plug
- Repair cause
- Check DTC memory page 01
-13

and/or check -G62-
- Check using output diagnostic test
mode page 01
-145
and/or check -
N80-

Heated Oxygen Sensor
(HO2S) -G39- faulty or dirty Oxygen Sensor (O2S) heater
-Z19- does not function - Check DTC memory page 01
-13

and/or check -G39-
- Check -Z19- page 24
-49

Fuel system pressure too
high or too low - Check fuel pressure regulator and
residual pressure page 24
-20


Constant 2.550 V Short to positive (B+) through:
Heated Oxygen Sensor
(HO2S) -G39- wiring Engine Control Module
(ECM) -J192- - Check -G39- page 24
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01-192

Display
fields Display on VAG 1551 scan tool
Malfunction cause
Malfunction repair
3/4
Constant value between 0.350 -
0.450 V Open circuit in:
Heated Oxygen Sensor (HO2S) -G39-
wiring Engine Control Module (ECM) -J192-- Check -G39- page
24
-49


Constant 0.000 V Short to ground in:
Heated Oxygen Sensor (HO2S) -G39-
wiring Engine Control Module (ECM) -J192-- Check -G39- page
24
-49


Notes on display field 4:
The display value at times must drop below 0.3 V
and exceed 0.6 V. Display values less than 0.40
V indicate lean condition; greater than 0.40 V
indicate rich condition.

HO2S voltage U (mV) vs. Lambda ( ) A - HO2S voltage (mV) high
Rich mixture (fuel excess or lack of air)
High CO value
B - Oxygen sensor probes voltage (mV) low
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01-193
Display group 011 Display
shows Specified display
value Designation
Basic setting
11
1 2 3 4 ... BTDC
1 = Ignition timing point without knock control and without idle speed control

... BTDC 2 = Ignition timing point with knock control and digital idle speed control (average
value for all cylinders)

_._ crankshaft 3 = Ignition timing point access to digital idle speed control
0 and/or 1 4 = Closed Throttle Position (CTP) switch function:
Open = 0; Closed = 1
Notes on display field 1:

At idle-Closed Throttle Position (CTP) switch closed-an ignition timing point of 12 BTDC is displayed. When the engine speed is increased-CTP switch open-the current ignition timing point is displayed without knock control
and without digital idle speed control.
Notes on display field 2:
Digital idle speed control is only active with Closed Throttle Position (CTP) switch closed.
Knock control is active starting at an engine load greater than 40% Display group 013 and/or 014.
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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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01-194
Display group 012 Display shows
Specified display value
Designation
Basic setting 12
1 2 3 4 ... RPM 1 = Momentary engine speed Display group 003, display field 1 ... % 2 = Momentary engine load Display group 003, display field 2 First map or second map 3 = Ignition timing point map switching

_._ crankshaft
4 = Ignition timing pt. retard by knock control (average of all cyl.)
Notes on display field 3:
The ignition timing point map switching is selected by knock control:

First map = Ignition timing point - basic map (98 octane)
Second map = Ignition timing point - map with reduced ignition angles (95 octane)
The ignition timing point difference between the first map and the second map is approx. 3 crankshaft. If an ignition timing
point retarded by approx. 4 crankshaft is recognized (display field 4), the second map is selected Display groups 013 and
014 for more exact evaluation.
The second ignition timing point map is selected:

If there is poor fuel quality (less than 95 RON)
If there are abnormal engine noises (subassemblies loose)
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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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01-195
Display group 013 Display shows
Specified display value
Designation
Basic setting 13
1 2 3 4 First map
and/or
second map 1 = Ignition timing point map switching display group 012, display field 3
_._ crankshaft
2 = Ignition timing point retarded by knock control (cylinder 1)

_._ crankshaft 3 = Ignition timing point retarded by knock control (cylinder 2)

_._ crankshaft 4 = Ignition timing point retarded by knock control (cylinder 3)
Display group 014 Display shows
Specified display value
Designation
Basic setting 14
1 2 3 4 First map
and/or
second map 1 = Ignition timing point map switching display group 012, display field 3
_._ crankshaft
2 = Ignition timing point retarded by knock control (cylinder 4)

_._ crankshaft 3 = Ignition timing point retarded by knock control (cylinder 5)

_._ crankshaft 4 = Ignition timing point retarded by knock control (cylinder 6)
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01-196
Display groups 013 and 014
Notes on display fields 2, 3 and 4:
Knock control is active starting at an engine load greater than 40%. If the engine load exceeds 40%, the current ignition timing
point retarding value is displayed; if the engine load drops below 40%, the last values used are displayed constantly.
If there is audible knocking without recognizable retarding of the ignition timing point, the engine speed should be increased
over 3500 RPM for 5 seconds to initiate the knock sensor malfunction recognition (On Board Diagnostic).
If an ignition timing point retarding value of one cylinder deviates from the others, the following malfunctions are possible:

Loose subassemblies
Corrosion on the harness connector
Engine damage (e.g. oil combustion with faulty piston)
If there are high ignition timing point retarding values on all cylinders of bank 1 or bank 2, the following malfunctions are
possible:
Corrosion on the harness connector display groups 015 and 016 Knock sensor tightening torque, 20 Nm (14 ft lb), not OK
Open circuit display groups 015 and 016 Knock sensor faulty
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01-197
Display group 015 Display shows
Specified display value
Designation
Basic setting 15
1 2 3 4 ___ RPM 1 = Momentary engine speed display group 003, display field 1 _._V 2 = Knock sensor signal (cylinder 1)
_._V 3 = Knock sensor signal (cylinder 2)
_._V 4 = Knock sensor signal (cylinder 3) Display group 016 Display shows
Specified display value
Designation
Basic setting 16
1 2 3 4 ___ RPM 1 = Momentary engine speed display group 003, display field 1 _._ V 2 = Knock sensor signal (cylinder 4)
_._ V 3 = Knock sensor signal (cylinder 5)
_._ V 4 = Knock sensor signal (cylinder 6)
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