21-16
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 1 of 34 Char
ge pressure leak test with VAG 1687
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE06.21.2
21-24
Mechanical air recirculation valve,
checking
Note:
The mechanical air recirculation valve is
upstream of the exhaust turbocharger. It is
opened via vacuum by the recirculating valve
for turbocharger -N249- under conditions of
overrun, idling and partial load. This reduces
the charge pressure upstream of the throttle
valve. A high turbocharger speed is thus
maintained.
Check the air recirculation valve if the engine is
not producing full power, or jerking when the
throttle is opened and closed.
Special tools and equipment
Hand vacuum pump VAG 1390
Pa
ge 13 of 34 Char
ge pressure leak test with VAG 1687
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE06.21.2
