Checking activation of exhaust gas recirculation valve N18 — AUDI

🧭 Before you start

Fits: Audi A4 B5 (8D)

• Renewed: engine control unit

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• Connect vehicle diagnostic, testing and information systemVAS 5051 and select vehicle system "“01 - Engine electronics”" from list. Ignition must be switched on Simos injection and ignition system (4-cyl.)01.
• Voltage testers with a low current draw do not go out completely between activation signals from engine control unit, but continue to glow slightly and become distinctly brighter on activation.
• Connect test boxV.A.G 1598/31 to connectors of wiring harness; do not connect engine control unit. Connect earth clamp of test box to earth (not shown in illustration) Simos injection and ignition system (4-cyl.)24.

🔧 Engine codes this applies to

📋 Procedure

1. Connect voltage testerV.A.G 1527 B to contacts (1) and (5) of the connector.
2. Connect vehicle diagnostic, testing and information systemVAS 5051 and select vehicle system "“01 - Engine electronics”" from list. Ignition must be switched on Simos injection and ignition system (4-cyl.)01.
3. Under selection menu (1) select the diagnostic function "“03 - Final control diagnosis”".
4. Press the button → until the valve for exhaust gas recirculation N18 is actuated. [Note: Voltage testers with a low current draw do not go out completely between activation signals from engine control unit, but continue to glow slightly and become distinctly brighter on activation.]
5. Exit function "“03 - Final control diagnosis”" by pressing the ← key.

6. Press "“06 - End output”".
7. Switch off ignition.
8. Connect test boxV.A.G 1598/31 to connectors of wiring harness; do not connect engine control unit. Connect earth clamp of test box to earth (not shown in illustration) Simos injection and ignition system (4-cyl.)24.
9. ⚠ To prevent damage to the electronic components, select appropriate measuring range before connecting the measuring cables and observe the test requirements. — Check for open circuit and short to positive or earth in the following wiring:
10. Eliminate open circuit in wiring (refer to current flow diagram).
11. Renew engine control unit.

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