check engine AUDI A4 1999 B5 / 1.G AEB Engine Turbocharger Boost Control And Checking

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Turbocharger boost controls,
checking

Boost pressure regulation, checking


- Connect VAG 1551 or VAG 1552 scan tool and
press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (with engine
running at idle) Page 01
-7 .
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 -1-, -1- and -4- to input display group number 114, and
press -Q- button to confirm input.
Read Measuring Value Block 114 1 2 3 4

Indicated on display (1-4 = display fields)
WARNING!
A second technician is required to operate the VAG 1551 scan tool
during the road test. - Road test car at wide open throttle at 4000 RPM.
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- Compare display with specified value for
wastegate bypass regulator valve duty cycle in
display field 4:

Specified value: 5-95 %
If displayed value is OK:

- Change engine RPM until duty cycle is within
specified value.

- Compare display with specified value for
corrected specific engine load in display field 2:

Specified value: 3.00-8.00 ms

- Compare display with specified value for actual
engine load in display field 3:

Specified value: must be same as corrected
specified engine load in display field 2 (with
tolerance of 0.50 ms)
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Display fields

1 2 3 4
Display group 114: Boost pressure regulation
Display xx.xx ms xx.xx ms xx.xx ms xx %
Indicates Specified
engine load Corrected specified
engine load Actual engine load Duty cycle of wastegate
bypass regulator valve
Range --- --- --- 0-99 %
Specified
value --- 3.00-8.00 ms Same as corrected specific engine load in
display field 2 (tolerance 0.50 ms)
5-99 %
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If the actual engine load is not within the
tolerance, possible malfunctions are:

Wastegate bypass regulator valve electrical
malfunction
Hoses for wastegate bypass regulator valve
disconnected or blocked
Wastegate bypass regulator valve -N75-
blocked
Air leaks between turbocharger and intake
manifold
Wastegate bypass regulator valve mechanical
controls sticking (linkage, shaft)
Turbocharger faulty (turbine blocked by foreign
object)
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Check voltage supply for wastegate bypass
regulator valve -N75-

Note:
Voltage supply for the wastegate bypass
regulator valve is provided by the fuel pump
relay.

Fuse for -N75- OK

- Disconnect harness connector from valve.

If LED does not light:
If wiring is OK: - Connect VAG 1527B LED test light between harness connector
terminal 1 and engine Ground.
- Operate starter motor.
LED test light must light up
- Check wiring for open circuit between terminal 1 to and fuse, according
to wiring diagram. Repair if necessary.
- Check fuel pump relay Page 24
-81
.
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Barometric Pressure (BARO) sensor,
checking


Note:
The signal from Barometric Pressure (BARO)
sensor -F96- influences:

Boost pressure limit
Mixture composition at engine start-up

Required special tools and test equipment
VAG 1551 or VAG 1552 Scan Tool (ST) with
VAG 1551/3 adapter cable
VAG 1598/22 test box
Multimeter US 1119 (Fluke 83 or equivalent)
VW 1594 connector test kit
Wiring diagrams

Checking

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- Connect VAG 1551 or VAG 1552 scan tool and
press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (with engine
running at idle) Page 01
-7 .
Rapid data transfer
HELP
Select function XX

Indicated on display
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ger boost controls, checkin
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pair&id=AUDI.B5.FU02.24.3

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- 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 -1-, -1- and -3- to input display group number 113, and press -Q-
button to confirm input.
Read Measuring Value Block 113 1 2 3 4

Indicated on display (1-4 = display fields)
- Compare displayed value with specified air pressure value (display field 4):

Display fields

1 2 3 4
Display group 113: Boost pressure regulation
Display xxx RPM xx.xx ms
xxx
xxxx mbar
1)

Indicates Engine speed
(in 40 RPM steps) Engine load Throttle valve angle Air pressure
Range 0-6800 RPM 0.00-8.50 ms
0-90
559-1118 mbar
Specified value 0 RPM 0.00 ms
0-5 0 m
400 m
1000 m
1013 mbar
970 mbar
900 mbar
Pa
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ger boost controls, checkin
g
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.3