LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Audi >> 1993 >> S4 2.2 P >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Air Induction Systems >> WASTEGATE By-Pass Regulator Valve >> Checking Actuation
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Checking Actuation

  1. Disconnect harness connector at wastegate by-pass regulator valve. See Figure.
  2. Connect (US 1115) LED tester (using VW 1594 connector test kit) to terminal No. 1 of harness connector, and to engine Ground (ground). See Figure.
  3. Operate starter for a few seconds.
  4. LED tester must light up, during starter operation. If NO: Verify that circuit breakers S72 and S75 are Okay.
  5. Check continuity between harness connector terminal No. 1 of wastegate by-pass regulator valve, and EVAP frequency valve circuit breaker S75. See Figure. Resistance must be 0.5 ohm maximum. See WIRING DIAGRAMS .
  6. Check continuity between EVAP frequency valve circuit breaker S75, and terminal No. 31 of fuel pump relay J17, relay position 6. See Fig 1. Resistance must be 0.5 ohm maximum. See WIRING DIAGRAMS .
  7. Check control signal to fuel pump relay. See FUEL PUMP RELAY CONTROL SIGNAL .
  8. Reconnect LED tester between terminal No. 1 of wastegate by-pass regulator valve connector, and engine ground. See Figure. Initiate Output Diagnostic Test Mode (DTM). See OUTPUT DIAGNOSTIC TEST MODE (DTM) in SELF-DIAGNOSTICS article. LED tester must light up.
    NOTE: Positive voltage must be available at terminal No. 1 of wastegate by-pass regulator valve connector, regardless of which Output DTM is called up.
  9. If LED tester does NOT light up, connect test box to Engine Control Module (ECM) wiring harness using (VAG 1598/5) adapter cable. See Figure. ECM remains disconnected.
  10. Check continuity between terminal No. 1 of wastegate by-pass regulator valve connector, and test box terminal 37. See Figure. Resistance must be 1.0 ohm maximum. See WIRING DIAGRAMS .
  11. If circuit is open: Repair wiring between terminal No. 37 of ECM connector, and terminal No. 1 of wastegate by-pass regulator valve connector.
  12. If continuity is Okay: Replace ECM. After replacement of ECM, see ECM IDENTIFICATION and ECM CODING under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS article.
  13. Disconnect test box and adapter cable. Reconnect ECM to vehicle wiring harness.
  14. Connect LED tester to terminals No. 1 and 2 of EVAP canister purge regulator valve harness connector. See Figure.
  15. Initiate Output Diagnostic Test Mode (DTM). See OUTPUT DIAGNOSTIC TEST MODE (DTM) in SELF-DIAGNOSTICS article. LED tester must blink when valve is activated.
  16. Connect test box to Engine Control Module (ECM) wiring harness using (VAG 1598/5) adapter cable. See CONNECTING VAG 1598 TEST BOX . ECM remains disconnected.
  17. If LED tester lights up continuously: Check wiring between terminal No. 2 of wastegate by-pass regulator valve connector, and terminal No. 33 of test box, for short circuit to ground, see Figure. See WIRING DIAGRAMS .
  18. If LED tester does NOT blink: Check continuity between terminal No. 2 of wastegate by-pass regulator valve, and terminal No. 33 of test box. Resistance must be 1.0 ohm maximum. See WIRING DIAGRAMS .
  19. If circuit is grounded or open between terminal No. 2 of wastegate by-pass regulator valve connector, and terminal No. 33 of ECM connector. Repair as necessary.
  20. If circuit is Okay: Replace ECM. After replacement of ECM, see ECM IDENTIFICATION and ECM CODING under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS article.
NOTE: Central electrical panel is under left side of dash. See Figure.
Fig 1: Identifying Central Electrical Panel Relays & Relay Terminal No. Positions
G00160043Courtesy of AUDI OF AMERICA, INC.
scientia non olet · About LEMON Manuals