1999 AUDI A4 wiring

28-33

- Connect hand-held multimeter VAG1526
(voltage measurement range) to the following
contacts on the test box:

Contact
Specification
3 + 2 approx.
battery voltage
3 + 1 approx.
battery voltage
62 + 2 approx.
battery voltage
If the specifications are not obtained:

- Check wiring.

Electrical Wiring Diagrams, Troubleshooting &
Component Locations
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Knock Sensor (KS) 1 -G61 and Knock
Sensor (KS) 2 -G66, checking


Notes:

It is not possible to carry out an electrical test of
the knock sensors themselves.
To ensure that the knock sensors function
properly it is important to keep exactly to the
specified tightening torque of 20 Nm (15 ft lb)
Use only gold-plated terminals when repairing
the terminals in the plug connectors for the
knock sensors.
Check for corrosion in connection between
knock sensor and wiring harness.

Checking knock sensors

Note: - Disconnect harness connector for relevant knock sensor in engine
compartment.
Component location overview Page 24
-5 .
In order to reach the connector for the knock sensor for cylinder bank
2, first remove the bolts securing the coolant reservoir and move the
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If there is a connection between the terminals.
Notes:
If there is no short circuit
Checking wiring between knock sensors and engine control module - Check for short circuits between all three terminals in knock sensor
connector (terminals 1 + 2, 1 + 3 and 2 + 3).
Specified value: There must be no contact between the wires (infinite
). - Replace knock sensor.
In order to reach the knock sensors, first remove the air duct Page 24
-43
.
Use special tool 3247 to remove the knock sensors.
- Check wiring for knock sensors.

- Connect VAG1598/31 test box to wiring harness for engine control
module. Do not connect to the engine control module itself Page 24
-
20
.
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- Check wiring connection from relevant sensor connector to...

- ....Engine Control Module (ECM) for open circuit and/or short to B+ or
Ground (GND).
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Knock Sensor (KS) 1 -G61 (Bank 1)
3-pin connector on
wiring harness, socket
VAG1598/31 test
box, socket
1 (Ground (GND)) 99
2 (signal) 106
3 (shielded) 108
Knock sensor (KS) 2 -G66 (Bank 2)
3-pin connector on
wiring harness, socket
VAG1598/31 test
box, socket
1 (Ground (GND)) 99
2 (signal) 107
3 (shielded) 108

Resistance in wiring: max. 1.5 ohm

- Repair any open/short circuit as necessary.
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Checking signal wire for Hall sensor
Checking Ground (GND) wire for Hall sensor: - Connect multimeter (Fluke 83 or equivalent) (voltage measurement
range) between engine Ground (GND) and socket 1 of connector.
Specified value: approx. 5 V
- Connect multimeter (Fluke 83 or equivalent) (voltage measurement
range) between engine Ground (GND) and socket 2 of relevant
connector.
Specified value: approx. battery voltage
- Connect VAG1598/31 test box to wiring harness for engine control
module. Do not connect to the engine control module itself Page 24
-
20
.

- Connect multimeter (Fluke 83 or equivalent) (resistance measurement
range) between socket 3 on connector and engine Ground (GND).
Specified value: Continuity
Resistance in wiring: max. 1.5 Ohms
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If all specifications are reached but the diode test
lamp does not flash (measurement taken
between terminals 1 and 2 without unplugging
connector and while operating starter):

- Replace relevant Hall sensor.
If specifications are obtained:

- Check wiring.

Checking wiring between hall sensor and
engine control module

- Connect VAG1598/31 test box to wiring harness
for engine control module. Do not connect to the
engine control module itself Page 24
-20
.

- Check wiring connection from Hall sensor to engine control module for
open circuit and/or short circuit to B+ or Ground (GND).
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Camshaft Position (CMP) Sensor 2 -G163
(Bank 2)
3-pin connector on
wiring harness, socket
VAG1598/31 test
box, socket
1 (B+) 98
2 (signal) 86
3 (Ground (GND)) 108
Camshaft Position (CMP) Sensor 1 -G40 (Bank
1)
3-pin connector on
wiring harness, socket
VAG1598/31 test
box, socket
1 (positive) 98
2 (signal) 87
3 (Ground (GND)) 108

Resistance in wiring: max. 1.5 ohm

- Repair any open/short circuit as necessary.
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