AUDI A4 1999 B5 / 1.G AFC Engine Knock Sensors Checking Workshop Manual

28-29


Knock sensors, checking

Notes:

To functionally check knock sensors Repair
Group 01, Read measuring value block, display
group 015 and/or 016.

Component locations page 28
-1 .

Knock sensors can not be checked electrically,
check DTC memory page 01
-13
.

Use connector insertion tool 3247 for knock
sensor removing and installing.
It is important that exact knock sensor
tightening torque of 20 Nm (15 ft lb) be
maintained to make sure that there is proper
knock sensor function.
Visually check the knock sensor connector for
corrosion.
When repairing or replacing knock sensor
connector terminals, ONLY replace with gold
plated terminals.

Checking knock sensor wiring
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- Disconnect knock sensor harness connectors in
engine compartment.

If there is a short circuit: - Check all three terminals in knock sensor harness connector for
shorting to each other.
Wires must not be short circuited to each other
- Replace knock sensor.
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28-30

Checking wiring between knock sensor and
ECM

- Connect VAG 1598/19 test box to ECM harness
connector page 01
-255
.

- Check wiring for continuity or short between
knock sensor and ECM using wiring diagram.

Terminal assignments (inside connector)
Knock Sensor (KS) 1 -G61- 1 - Ground (GND) wire
2 - Signal wire
3 - Shield
- Check signal wire for continuity between harness connector terminal 2
(in engine compartment) and test box socket A13.

Specified value: max. 1 - Check Ground (GND) wire for continuity between harness connector
terminal 1 and test box socket A14.

Specified value: max. 1 - Check shielding for continuity between harness connector terminal 3
(in engine compartment) and engine Ground.

Specified value: max. 1
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If specified values are not obtained, repair open or short circuit.
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28-31

Knock Sensor (KS) 2 -G66-

- Check signal wire for continuity between
harness connector terminal 2 (in engine
compartment) and test box socket A15.


Specified value: max. 1
- Check Ground (GND) wire for continuity
between harness connector terminal 1 and test
box socket A14.


Specified value: max. 1
- Check shielding for continuity between harness
connector terminal 3 (in engine compartment)
and engine Ground.


Specified value: max. 1 If the specified values are not obtained:

- Eliminate open or short circuit in wiring.
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28-32


Knock sensor 1 (bank 1):
Knock sensor terminal
number ECM connector A or engine ground
(GND)
1 (Signal)
2 (Ground)
3 (shield) A13
A14
Engine Ground (GND)
Knock sensor 2 (Bank 2):
Knock sensor terminal
number ECM connector A or engine ground
(GND)
1 (Signal)
2 (Ground)
3 (Shield) A15
A14
Engine Ground (GND)
Pa
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