Checking charge air system for leaks, engines with code letters AXX, BPY, BWA — AUDI

🧭 Before you start

Fits: Audi A3 (8P, 2003–2012)

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• Make sure knob is pulled out before turning pressure control valve (2).
• If sight glass contains water, loosen drain plug and drain water (6).
• The pressure must not exceed 0.5 bar. If the pressure is set too high this can damage the engine. — Open valve (4) and wait until test system is pressurised. Re-adjust pressure to 0.5 bar if necessary.

🔧 Engine codes this applies to

📐 67 workshop diagrams for AXX

Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.

📋 Procedure

1. Remove noise insulation tray General body repairs, exterior50Body - front, noise insulation.
2. Release clip (A) and detach hose (B) from charge air pipe.
3. Fit adapterV.A.G 1687/5 onto charge air hose (A) and turn adapter through approx. 90° (B).
4. Unscrew pressure control valve (2) all the way and close valves (3) and (4). [Note: Make sure knob is pulled out before turning pressure control valve (2).]
5. Connect charge air system testerV.A.G 1687 as illustrated.

6. Connect pressure hose (1) (compressed air supply line) to charge air system testerV.A.G 1687. [Note: If sight glass contains water, loosen drain plug and drain water (6).]
7. Open valve (3).
8. Adjust pressure to 0.5 bar via pressure control valve (2).
9. ⚠ The pressure must not exceed 0.5 bar. If the pressure is set too high this can damage the engine. — Open valve (4) and wait until test system is pressurised. Re-adjust pressure to 0.5 bar if necessary.
10. Check charge air system for visible or audible leaks and apply commercially available leak detecting spray or use ultrasonic testerV.A.G 1842. [Note: A small amount of air escapes through the valves and enters the engine. Therefore it is not possible to perform a pressure retention test.Operation of ultrasonic testerV.A.G 1842Operating instructions.Release pressure by detaching coupling from adapterV.A.G 1687/5 before removing adapter.Hose connections and hoses for charge air system must be free of oil and grease before assembly.]
11. Install air pipes with plug-in connectors .

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