1996 AUDI A4 check engine

28-40
Evaluation display groups 020/021/022/023/024 - ignition angle retardation
Indicated on display
Possible cause
Corrective action
All cylinders more than 12 KW
Knock sensor faulty- Check knock sensor Page 28
-41

Harness connector corroded
Knock sensor incorrect
tightening torque - Loosen knock sensors and tighten to 20
Nm
Engine accessories loose- Secure engine accessories
Poor fuel quality- Change fuel quality
(see operating instructions)
One cylinder deviates significantly from
the others Harness connector corroded- Check knock sensor Page 28
-41

Engine damage
Repair Manual, Engine Mechanical,
Repair Group 15 - Check compression pressure:

Engine accessories loose- Secure engine accessories
Pa
ge 45 of 65 I
gnition s
ystem, checkin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.28.1

28-42
Component location Overview of Component
Locations, page Page 24
-5

Notes:

Knock Sensor (KS) 1 -G61- and Knock Sensor
(KS) 2 -G66- themselves cannot be electrically
tested.
Use only gold-plated terminals when servicing
harness connector for knock sensors.
For the knock sensors to function properly, it is
important that tightening torque be exactly 20
Nm.
Check harness connector from knock sensor to
wiring harness for corrosion.

Check knock sensors

Note:
Coolant reservoir screws must be removed and coolant reservoir must be
placed to side in order to access harness connector for knock sensor for
bank 2. The coolant hoses can remain connected. - Disconnect the harness connector of the relevant knock sensor in
engine compartment.
Pa
ge 47 of 65 I
gnition s
ystem, checkin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.28.1

28-43


Check wires from knock sensors to Engine Control Module (ECM). - Check all three terminals at knock sensor connector for short circuit to
each other (terminal 1+2, 1+3, 2+3).

Specification: (no continuity) - the wires must not have any
connection to each other.
- If there is no connection , replace knock sensor.
- If no short circuit is detected, check knock sensor wires:
- Connect VAG1598/31 test box at wiring harness to ECM, do not
connect ECM Page 24
-17
.
- Check the following wire connections for open circuit and short circuit
to Ground (GND) and B+:

Knock Sensor (KS) 1 -G61- Harness connector
Terminal
VAG1598/31 test box
Socket
1 (signal) 106
2 (Ground -GND-) 99
3 (shielding) 108
Pa
ge 48 of 65 I
gnition s
ystem, checkin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.28.1

28-46
Component location Overview of Component
Locations, page Page 24
-5

Notes:

Camshaft Position (CMP) Sensor -G40- is
located at rear of left cylinder block (bank 2).
Camshaft Position (CMP) Sensor 2 -G163- is
located at front of right cylinder block (bank 1).

Checking activation

- Slide back rubber grommet at connector of the
respective Camshaft Position (CMP) Sensor
(connector remains connected to Camshaft
Position (CMP) Sensor).

Note:
Connector socket numbers are shown on the rear side of the connector. - Connect VAG1527B voltage tester between sockets 2 (CMP sensor
signal) and 1 (B+).
- Operate starter for a few seconds.

LED must blink briefly at every second engine rotation.
Pa
ge 51 of 65 I
gnition s
ystem, checkin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.28.1

28-47

Note:
Voltage testers do not go out completely during
low current pick-up between activations by the
ECM, but rather continue to glow a little and then
get significantly brighter during activation.
If LED does not blink:

Checking voltage supply

- Disconnect connector at respective Camshaft
Position (CMP) sensor.

- Switch ignition on.

- Connect multimeter for voltage measurement as follows:Harness connector
Terminal
Measure to
1 Engine Ground (GND)

Specification: about 5 V
Pa
ge 52 of 65 I
gnition s
ystem, checkin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.28.1

28-48

Checking signal wire

Checking Ground (GND) wire
If all specified values are being reached and the LED does not blink
(measured between terminal 1 and 2 with starter and connector
connected): - Connect multimeter for voltage measurement as follows:Harness connector
Terminal
Measure to
2 Engine Ground (GND)

Specification: approx. battery voltage
- Connect multimeter for voltage measurement as follows:
Harness connector
Terminal
Measure to
3 B+

Specification: approx. battery voltage
- Repair open circuit or short circuit if necessary.
- Replace respective Camshaft Position (CMP) sensor.
Pa
ge 53 of 65 I
gnition s
ystem, checkin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.28.1

28-49
If specified values are not obtained:

Checking wire connections between
Camshaft Position (CMP) sensor and Engine
Control Module (ECM)

- Connect VAG1598/31 test box at wiring harness
to ECM, do not connect ECM Page 24
-17
.

Camshaft Position (CMP) Sensor 2 -G40- (bank 2)
Camshaft Position (CMP) Sensor 2 -G163- (bank 1) - Check the following wire connections for open circuit and short circuit
to Ground (GND) and B+: Harness connector
Terminal
VAG1598/31 test box
Socket
1 (B+) 98
2 (signal) 86
3 (Ground -GND-) 108
Harness connector
Terminal
VAG1598/31 test box
Socket
1 (B+) 98
Pa
ge 54 of 65 I
gnition s
ystem, checkin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.28.1

28-50

- Repair open circuit or short circuit if
necessary.

- If, after erasing DTC memory for the sake of the
test, a DTC relating to the Camshaft Position
(CMP) sensor (hall sensor) is indicated again,
even though all previous tests were OK, the
following malfunction is possible:


Shutter wheel for Camshaft Position (CMP)
sensor is not aligned properly.

Check phase position of Camshaft Position
(CMP) sensor

- Connect VAS5051 tester or VAG1551 scan tool
and select the control module for engine
electronics using "address word" 01 Page 01
-
9 .

Engine must run at idle for this.Rapid data transfer
HELP
Select function XX

When indicated on display:
- Press buttons -0- and -8- to select "Read Measuring Value Block" and
press -Q- button to confirm input.
Read Measurin
g Value Block
Q
Input display group number XXX

When indicated on display:
Pa
ge 56 of 65 I
gnition s
ystem, checkin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.28.1