display AUDI TT 1998 8N / 1.G AEB ATW Engines Charge Air System With Turbocharger Workshop Manual

21-49

Note:
The recirculating valve for turbocharger -N249-
and wire connections are monitored by the
Engine Control Module (ECM).

- Connect VAS5051 tester or VAG1551 scan tool
and select control module for engine electronics
using "address word 01". Engine must run at idle
for this:

Repair Manual, 1.8 Liter 4-Cyl. 5V Turbo Fuel
Injection & Ignition, Repair Group 01 If a malfunction relating to the recirculating valve
for turbocharger -N249- is displayed:

- Disconnect hoses from valve; harness connector
remains connected.

- Attach assisting hose to one connection of
valve.
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- Initiate output Diagnostic Test Mode (DTM) and
activate the recirculating valve for turbocharger -
N249-:

Repair Manual, 1.8 Liter 4-Cyl. 5V Turbo Fuel
Injection & Ignition, Repair Group 01 Output Diagnostic Test Mode Recirc. valve for turbochar
ger -N249

Indicated on display
If valve does not click:
If valve does not open and close properly:
Checking internal resistance Valve must click...
...and must open and close (can be tested by blowing into assisting
hose).
- Check internal resistance of valve.
- Replace recirculating valve for turbocharger -N249-.
- Disconnect harness connector at valve.

- Connect multimeter at valve for resistance measurement.

Specified value: 27-30
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Notes: - Turn turbocharger tester on and select measuring range -I- (absolute
pressure).
- Connect test hose to connection barb -I-.
Hoses must be properly connected and there must be no possibility of
leaks, otherwise incorrect readings may result. Make sure that the test hose is not pinched at the hood or at the side
window. By pressing memory button "M" on turbocharger tester, the last test
value is saved until either memory button "M" is pressed again or the
turbocharger tester is shut-off. A blinking comma in the display field indicates that a value has been
saved. An arrow appears in the top left corner of the display field if the
turbocharger tester battery voltage drops below the permitted
threshold. Before testing, drive vehicle rapidly for at least 3 km on a road that
does not require stopping (i.e. traffic lights or similar). A second technician is required because the indicated values must be
read out while the vehicle is being driven.
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Rapid data transferSelect function XX

When indicated on display:
- Press buttons -0- and -8- to select "Read Measuring Value Block" and
press -Q- button to confirm input.
Read Measuring Value Block
Q
Input displa
y group number XXX

When indicated on display:
- Press buttons -0-, -0- and -4- to select "display group number 004" and
press -Q- button to confirm input.
Read Measuring Value Block 4
1
2
3
4

Indicated on display
Do not continue with test until intake air temperature in display field 4 is
20-50 C if necessary, warm up vehicle by driving. - Press -C- button.
Read Measuring Value Block
Q
Input displa
y group number XXX

When indicated on display:
- Press buttons -1-, -1- and -5- to select "display group number 115" and
press -Q- button to confirm input.
Read Measuring Value Block 115
1
2
3
4

Indicated on display (1-4 = display fields)
- Accelerate vehicle in 3rd gear at full throttle from 2000 RPM and
observe tachometer.
- At approx. 3000 RPM, press the print button on the VAS5051 or
VAG1551 and simultaneously press the memory button -M- on the
VAG1397A.
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Note:
The height of the charge air pressure should be
determined using the VAG1397/A turbocharger
test tool, the VAS5051 tester or the VAG1551
Scan Tool is used to determine whether the
charge air pressure is also being recognized in
the control module.

Specification on VAG1397A: 1.450-1.700 bar
Read Measuring Value Block 115 3000 RPM
42%
1770 mbar
1770 mbar

If the specification is exceeded or not met:
Repair Manual, 1.8 Liter 4-Cyl. 5V Turbo Fuel Injection & Ignition,
Repair Group 01
Specified value on VAS 5051 or VAG 1551 Display field 4: 1450-1700
mbar
- Check DTC memory of Engine Control Module (ECM):
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- Initiate output Diagnostic Test Mode (DTM) and
activate the wastegate bypass regulator valve -
N75-.

Repair Manual, 1.8 Liter 4-Cyl. 5V Turbo Fuel
Injection & Ignition, Repair Group 01 Output Diagnostic Test Mode Waste
gate B
ypass Re
gulator Valve -N75

Indicated on display
If valve does not click:
If valve does not open and close properly:
Checking internal resistance Valve must click...
...and must open and close (can be tested by blowing into assisting
hose).
- Check internal resistance of valve.
- Replace wastegate bypass regulator valve -N75-.
- Disconnect harness connector at valve.

- Connect multimeter at valve for resistance measurement.

Specified value: 25-35
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(en
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yp
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pair&id=AUDI.B5.GE02.21.3