1999 AUDI A4 sensor

28-45

Camshaft Position (CMP) sensor 1 -G40
and Camshaft Position (CMP) sensor 2 -
G163, checking


Notes:

Component locations of Hall sensors Page 24
-5 .

The Camshaft Position (CMP) Sensor 1 -G40 is
located at the rear of the right-hand cylinder
head (Bank 1).
The Camshaft Position (CMP) Sensor 2 -G163
is located at the front of the left-hand cylinder
head (Bank 2).

Checking activation of Hall sensor (camshaft
position sensor)
Use test leads VAG1594 connector test kit when
carrying out the following tests.

- Push back rubber grommet on relevant Hall
sensor connector.

- Connect VAG1527 diode test lamp to terminals 1 and 2 of hall sensor
connector from behind (without disconnecting connector from hall
sensor).
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- Operate starter for few seconds.
The diode test lamp should blink briefly once
every two engine revolutions.

Note:
Diode test lamps with a low current draw
continue to glow faintly between impulses from
the engine control module (rather than going out
completely) and become much brighter when
receiving an impulse.
If the diode test lamp does not flash, test the
voltage supply.

Checking voltage supply for Hall sensor

- Disconnect harness connector from relevant Hall
sensor.

- Switch ignition on.
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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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If all the test results so far have been OK but a
malfunction related to the camshaft position
sensor (Hall sensor) is displayed again after
erasing the DTC memory as a test measure, the
following might be the cause:

- Rotor ring (trigger wheel) for camshaft position
sensor (Hall sensor) misaligned; test phase
position.

Checking phase position of Hall sensor

- Connect vehicle diagnostic, testing and
information system VAS5051 or VAG1551 scan
tool and select engine electronics control
module by entering address word "01" Page
01
-9 . When doing this the engine must be
idling.
Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -8- to select function "Read Measuring Value
Block" and confirm entry with -Q- button.
Read Measurin
g Value Block
Input displa
y group number XXX

Indicated on display:
- Press buttons -0-, -9- and -3- to select "Display Group 093" and
confirm entry with -Q- button.
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Read Measuring Value Block 93
1
2
3
4

Indicated on display
- Check specified display values for Hall sensors.

Display fields

1 2 3 4
Display Group 093: Phase positions of Hall sensors (Bank 1 and Bank 2) with engine idling
Display xxx RPM xx %
0 6 KW
0 6 KW
Indicates Engine
speed
(RPM) Engine
load Phase position
Bank 1 Phase position
Bank 2
Work
range min.: 750
RPM
max.: 6800
RPM min.: 15
%
max.:
175 % -20.3 to 14.8 KW
-20.3 to 14.8 KW
Specified
value 750 - 850
RPM
0 6 KW
0 6 KW
Note
If readouts do not match specifications, unbolt Hall sensor and check whether
rotor ring is properly mounted on camshaft. If it is incorrectly mounted, the
locating lug will be flattened when the securing bolt is tightened. Also check
valve timing.
Repair Manual, 2.7 Liter V6 5V BiTurbo Engine Mechanical, Engine Code(s): APB,
Repair Group 13, Crankcase ventilation, Ribbed belt removing and installing, Timing belt removing and installing

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