Checking turbocharger and charge pressure regulating valve - vehicles with throttle cable — AUDI

🧭 Before you start

Fits: Audi A3 (8L, 1996–2003)

• Special tools named: V.A.G 1397

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• To avoid accident risks when road testing the vehicle with test equipment, always observe the relevant safety precautions . — Route test hose under rear edge of bonnet and through right window into passenger compartment.
• Connect up vehicle diagnostic, testing and information systemVAS 5051 with diagnosis leadVAS 5051/1, press vehicle self-diagnosis key and select vehicle system "“01 - Engine electronics”". Engine must be idling.
• If the self-diagnosis function of the control unit detects a fault in the charge pressure control system, the duty cycle in display zone (4) is set to 5 % (constant).

🔧 Engine codes this applies to

📋 Procedure

1. Take off engine cover panel (arrows).
2. ⚠ To avoid accident risks when road testing the vehicle with test equipment, always observe the relevant safety precautions . — Route test hose under rear edge of bonnet and through right window into passenger compartment.
3. Switch on turbocharger tester and set measuring range selector switch to position (I) (absolute pressure).
4. Attach test hose to connection (I). [Note: Ensure absolute leakproof connection of hoses to avoid measurement errors.Take care not to trap test hose at bonnet and side window.Pressing memory button (M) on turbocharger tester causes last measured value to be stored until memory button (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 vehicle moderately fast for at least 3 km (without stopping at traffic lights etc.).]
5. Accelerate vehicle in 3rd gear from 2000 rpm at full throttle while a second mechanic observes the rev counter.

6. Second mechanic should press memory button (M) on V.A.G 1397 A at approx. 3000 rpm.
7. Move selector lever in position "“2”" and start to drive.
8. Accelerate to 3000 rpm and wait until the gearbox engages 2nd gear.
9. Depress accelerator pedal with kick-down (gearbox will not select a lower gear at this engine speed).
10. Second mechanic should press memory button (M) on V.A.G 1397 A at approx. 4500 rpm. [Note: On vehicles with automatic gearbox the charge pressure test is not always a reliable indication of the proper function of the charge pressure control system. Therefore, if the pressure value is close to the lower tolerance limit, check the load signal in order to test the charge pressure control function.]
11. Connect up vehicle diagnostic, testing and information systemVAS 5051 with diagnosis leadVAS 5051/1, press vehicle self-diagnosis key and select vehicle system "“01 - Engine electronics”". Engine must be idling.
12. From the list (1) select diagnostic function "“08 - Read measured value block”".
13. Press keys 25 on keypad (2) to select "“Display group 25”" and confirm entry by pressing key Q.
14. Accelerate vehicle at a constant rate and have a second mechanic check the displays in zones (2) and (3). [Note: If the self-diagnosis function of the control unit detects a fault in the charge pressure control system, the duty cycle in display zone (4) is set to 5 % (constant).]
15. Find fault causes using fault table below.

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