audi Workshop Repair Guides

Audi Workshop Service and Repair Manuals

ABOUT US
Testing charge pressure control > < Rules for cleanliness

A4 Mk1

6-Cylinder engine (5-valve turbo), Mechanics
Charge air system with turbocharger
Checking turbocharger and charge pressure regulating valve

Safety notes

Note the following points if test equipment has to be used during a road test:

Warning
  • ◆ Test equipment must always be secured on the rear seat and operated from the rear seat by a second person.
  • ◆ If test equipment is operated from the front passenger seat, the occupant could be injured by the passenger's airbag in an accident.

Special tools, testers and auxiliary items

  • ◆ Turbocharger tester V.A.G 1397 A
  • ◆ Fault reader V.A.G 1551 or V.A.G 1552 with cable V.A.G 1551/3

Requirements for test:

  • ● Fault memory has been interrogated
 
A34-0163

=> Motronic injection and ignition system (6-cylinder turbo); Repair group 01; Interrogating and erasing fault memory

  • ● Final control diagnosis has been performed

=> Motronic injection and ignition system (6-cylinder turbo); Repair group 01; Final control diagnosis

  • ● All vacuum connections airtight
  • ‒ → Loosen bolts -arrows- and remove engine cover panel -B-.
 
A21-0054
  • ‒ → Connect T-piece with measuring hose of turbocharger tester V.A.G 1397 A to fuel pressure regulator -arrow-.
  • ‒ Route measuring hose under rear edge of bonnet and into passenger compartment via right-hand window.
 
V21-0096
  • ‒ → Switch on turbocharger tester and set measuring range selector switch to position -I- (absolute pressure).
  • ‒ Connect measuring hose to connection -I-.

Notes:

  • ◆ Hose connections must be completely airtight, otherwise measurements will not be correct.
  • ◆ Ensure that measuring hose is not pinched at bonnet or side window.
  • ◆ Pressing memory key M on turbocharger tester will store the last measured value until memory key M is pressed again or tester is switched off.
  • ◆ The decimal point in the display flashes to indicate that the value is being stored.
  • ◆ If the battery voltage of the turbocharger tester drops below the minimum level, an arrow will appear at the top left of the display.
  • ◆ Before performing the test, drive the vehicle at a brisk speed for at least 3 km (without stopping at traffic lights etc.).
  • ◆ A second mechanic is required to note the readings on the tester when the vehicle is moving.
  • ◆ Observe safety notes .
 
V21-0096
  • ‒ Accelerate the vehicle from 2000 rpm at full throttle in fourth gear, and watch the rev counter.
  • ‒ → Press memory key -M- on turbocharger tester at 3000 rpm.
    • ‒ Specification: 1.650 ... 1.750 bar

Note:

If no charge pressure is obtained and a throbbing noise can be heard in the engine compartment, the causes can be as follows:

  • ◆ Air recirculation valve defective.
  • ◆ Vacuum line to air recirculation valve leaking or has become disconnected.

Testing charge pressure control > < Rules for cleanliness