LEMON Manuals: Even more car manuals for everyone
Home >> Infiniti >> 2003 >> QX4 RWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0505: Idle Speed Control System >> Diagnostic Procedure

Diagnostic Procedure

  1. Turn ignition off. Disconnect IACV-AAV valve 6-pin harness connector. IACV-AAV valve is located on throttle body. Turn ignition on. Measure voltage between ground and IACV-AAV valve harness connector terminals No. 2 and 5 (Red wires). See Fig 1. If battery volage does not exist, go to next step. If battery voltage exists, leave harness connector disconnected and go to step  3.
  2. Check following:
    • Check for poor, loose, corroded or damage to terminal connections in in-line harness connectors E1 and M1. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
    • Check for poor, loose, corroded or damage to terminal connections in in-line harness connectors F22 and M33.
    • Check for poor, loose, corroded or damage to terminal connections in in-line harness connectors F6 and F101.
    • Check for open or short in circuits between IACV-AAC valve and ECM relay.
    If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST .
  3. Turn ignition off. Disconnect ECM 116-pin harness connector. For ECM location, see Figure. Check continuity in specified circuits between ECM and IACV-AAC valve. See CHECKING IACV-AAC VALVE CIRCUITS  table. See Figure and Fig 1 . Also, check circuits for short to ground or short to voltage. If problem is found, go to next step. If no problem is found, leave IACV-AAC valve harness disconnected and go to step  5.
    CHECKING IACV-AAC VALVE CIRCUITS

    ECM Terminal No. IACV-ACC Valve Terminal No. Wire Color
    6 1 Purple/Green
    7 4 Gray
    8 3 Yellow
    17 6 Gray/Blue
  4. Check following:
    • Check for poor, loose, corroded or damage to terminal connections in in-line harness connectors F6 and F101. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
    • Check for open or short in circuits between IACV-AAC valve and ECM.
    If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST .
  5. Measure resistance between IACV-AAC valve terminals as follows:
    • Measure between IACV-AAC valve terminals No. 1 and 2, then 2 and 3.
    • Measure between IACV-AAC valve terminals No. 4 and 5, then 5 and 6.
    Resistance should be about 20-24 ohms at 68°F (20°C). If no problem is found, go to next step. If problem is found, replace IACV-AAC valve. After repair, repeat DTC CONFIRMATION TEST .
  6. Connect any disconnected harness connectors. Turn ignition on and off while listening to IACV-AAC valve. Valve should make noise as ignition is turn from off to on. If valve does not operate as specified, go to next step. If valve operates as specified, go to step  8.
  7. Replace IACC-AAC valve. Perform idle air volume learning procedure. See IDLE AIR VOLUME LEARNING  under PROGRAMMING. If result is complete, testing is complete. After repair, repeat DTC CONFIRMATION TEST .
  8. Turn ignition off. Connect any disconnected vacuum hoses and harness connectors. Test drive vehicle about 10 minutes until engine and transmission is at normal operating temperature. Let engine idle. Check target idle speed. If idle speed is 700-800 RPM, go to next step. If idle speed is not as specified, perform idle air volume learning procedure. See IDLE AIR VOLUME LEARNING  under PROGRAMMING.
  9. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
Fig 1: Identifying IACV-AAC Valve Harness Connector Terminals
G00015007Courtesy of NISSAN MOTOR CO., U.S.A.
scientia non olet · About LEMON Manuals