AUDI A8 2000 D2 / 1.G AHA Engine Camshaft Adjustment System Checking Workshop Manual

28-29


Camshaft adjustment system,
checking

Required special tools and test equipment

VAG1551 Scan Tool (ST) with VAG1551/3
adapter cable
Multimeter US1119 (Fluke 83 or equivalent)
VW1594 connector test kit

Function
The camshaft adjustment is dependent on
engine speed and load. The electrical solenoid
valves for camshaft adjustment (-N205- and -
N208-) are switched to apply oil pressure to the
mechanical camshaft adjusters, which adjusts
the camshaft timing.
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Camshaft adjustment function, checking


- Connect VAG1551/1552 Scan Tool (ST) and
press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (engine running at
idle) page 01
-8 .
Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -8- to select "Read Measuring Value Block"
function 08, and press -Q- button to confirm input.
Read Measurin
g Value Block
HELP
Input displa
y group number XXX

Indicated on display
- Press buttons -0-, -9- and -0- to input display group number 90 (090),
and press -Q- button to confirm input.
Read Measuring Value Block 90 1 2 3 4

Indicated on display (1-4 display groups)
Notes:
Display field 2 indicates whether the engine control module has activated
the camshaft adjustment.
Display fields 3 and 4 show whether the camshaft adjustment did actually
occur (via input from sensors):
"CS-ctrlOFF:" camshaft adjustment is not active."CS-ctrlON:" camshaft adjustment is active (this can only be attained
during a test drive)
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Normal Position: -3.0 to 6.0 KW.Shifted position: 16.0 KW to 25.0 KW.
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Note:
If, during the test drive, display field 3 and/or 4
displays a value between 6.0 KW and 16.0
KW, the electrical valves for camshaft adjustment
have switched the oil pressure to the respective
mechanical camshaft adjuster, but it cannot
attain the correct end position (e.g. due to
sluggishness).
WARNING!

A second technician is required to operate
the VAG1551 scan tool during the road test.
Safety precautions page 24
-9 .

- Accelerate from rest in 1st gear (manual) or with
selector lever in "2" position (automatic).

- Check specified values for camshaft adjustment
(display fields 2-4)
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Display fields

1 2 3 4
Display group 90: Camshaft adjustment
Display xxx RPM CS-ctrlOFF
CS-ctrlON x,x KW
x,x KW
Indicates Engine speed
(in 40 RPM
steps) Camshaft adjustment
off/on Response of camshaft
adjustment Bank 1 Response of camshaft
adjustment Bank 2
Work range 1000 - 5000
RPM ---
-3.0 to 25.0 KW
-3.0 to 25.0 KW
Specified
Value 620 - 740
RPM
(all-wheel
drive)
or
740 - 860
RPM
(front-wheel
drive) CS-ctrlOFF
-3.0 to 6.0 KW
(normal position)
-3.0 to 6.0 KW
(normal position)

....RPM (test
drive) CS-ctrlON
16.0 to 25.0 KW
(shifted position)
16.0 to 25.0 KW
(shifted position)
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--- If the specified values are not attained, check solenoid valves for camshaft adjustment
page 28
-33
.
If specified values are attained:

-
Press button.
- Press buttons -0- and -6- to select "End Output"
function 06, and press -Q- button to confirm
input.
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Valves for camshaft adjustment,
checking


Note:
Installation location page 24
-1

- Connect VAG1551/1552 Scan Tool (ST) and
press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (with engine
running at idle) page 01
-8 .
Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -3- to select "Output Diagnostic Test Mode"
function 03.
Rapid data transfer
Q
03 - Output Diagnostic Test Mode

Indicated on display
- Press -Q- button to confirm input.
Output Diagnostic Test Mode Camshaft adjustment 1

Indicated on display
If the valves do not click: - Check using output DTM and activate camshaft adjustment page
01
-51
.
Valves 1 and 2 for camshaft adjustment, -N205- and -N208-, must click
audibly.
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- Check as described in test procedures that follow.
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Checking solenoid valves for camshaft
adjustment electrically

- Disconnect harness connector from valve.

If resistance is not as specified: - Using multimeter with auxiliary wires from VAG1594, measure
resistance across terminals on valve.
Specified value: 10-18 ohms
- Replace solenoid valve.
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Checking voltage supply of valves for
camshaft adjustment

- Disconnect harness connector from valve.

If LED does not light up, conduct the following tests:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder - Connect LED tester VAG1527 between engine ground and terminal 1
of connector (B+).
- Crank starter for several seconds (engine can start).
LED in voltage tester must light up.
- Check fuse for valves for camshaft adjustment.
- Check wiring from terminal 1 on 2-pin connector to fuse for continuity
per wiring diagram. - Check fuel pump relay and signal to relay page 24
-95
.
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