fuel pressure AUDI A4 1995 B5 / 1.G AEB ATW Engines Charge Air System With Turbocharger Workshop Manual

- Using T-piece connect test hose from VAG1397A Turbocharger Tester
between intake manifold and fuel pressure regulator.
- Guide test hose over rear corner of hood, through passenger side
window and into vehicle interior.
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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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charge air pressure regulation Diagnostic Trouble Codes (DTC) Diagnostic Trouble
Code (DTC) Charge air pressure
Possible causes
Charge air pressure
too low
Measured value below
1.450 bar or 1450 mbar
Wastegate bypass regulator valve -N75- faultyWire to wastegate bypass regulator valve -N75- faultyCharge air pressure regulator valve in turbocharger is stuck in
open position Leak between turbocharger and intake manifoldMechanical recirculation valve faultyTurbocharger malfunctioning
Charge air pressure
too high
1)
Measured value above
1.700 bar or 1700 mbar
Vacuum diaphragm for charge air pressure regulator valve
faulty Hoses to vacuum diaphragm for charge air pressure regulation
valve (via wastegate bypass regulator valve -N75-) leaky Charge air pressure regulator valve in turbocharger is stuck in
closed position
1) If charge air pressure is too high, the fuel supply is shutoff to protect the engine. The engine misfires at high engine
speeds.
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Note:
The charge air pressure sensor -G31- 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
- Check DTC memory of Engine Control Module
(ECM):

Repair Manual, 1.8 Liter 4-Cyl. 5V Turbo Fuel
Injection & Ignition, Repair Group 01 If a malfunction relating to the charge air
pressure sensor -G31- is indicated:

Checking voltage supply

- Disconnect harness connector at charge air
pressure sensor.
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Charge pressure leak test with VAG
1687


Intake system, checking for leaks using VAG
1687 Diagnostic Tool
Diagnostic trouble codes (DTCs) related to fuel
trim, charge pressure or mass air flow (MAF)
may be caused by:

Leaking (worn/torn) intake hoses during charge
conditions
Incorrectly torqued or improperly placed clamps
on intake hoses etc. causing leaks during
charge conditions

Check the charge air pressure system using the VAG 1687 Charge air
system tester.
Special tool VAG 1687 Charge air system tester preliminary set-up

- Back off pressure regulator knob -2- of VAG 1687 fully to protect gauge
when shop air supply is applied to assembly.
Pa
ge 31 of 42 Char
ge air s
ystem with turbochar
ger
(en
gine code ATW
)
11/18/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE02.21.3