1999 Infiniti Q45 BaseFACTORY OEM SERVICE PROCEDURE

Testing Procedure

To ensure correct diagnosis and repair, testing should be done in the following sequence:

  1. Ensure all customer complaints or observations are recorded. Test drive vehicle with customer, when necessary, for malfunction verification.
  2. Retrieve and record stored DTCs and freeze frame data stored. Clear freeze frame data and erase DTC(s). See CLEARING CODESΒ .
  3. Recreate conditions in which malfunction occurred to reset DTC. If DTC is detected, go to step Β 5. If malfunction is not detected, consider the following conditions to recreate an intermittent malfunction:
    • Drive vehicle on rough road or with engine vibrating at idle (with A/C on).
    • Incident occurs on only extremely hot or cold days.
    • Water may intrude into connectors and cause corrosion between connector terminals.
    • Operate multiple accessories (P/W, P/L, A/C, wipers, lights, etc.).
    • Start vehicle either hot or cold.
    • Wiring harnesses may be checked by gently wiggling wire harness during testing. Relays and sensors may be checked by gently tapping during testing.
      NOTE: Perform DTCs in order of priority. See MULTIPLE DTC PRIORITY IDENTIFICATIONΒ  table.

    If malfunction is still not detected, go to next step.

  4. Perform DTC CONFIRMATION TEST at the beginning of each DTC diagnostic test to set appropriate DTC. See appropriate SELF-DIAGNOSTICS article.
  5. If DTC is set, perform appropriate procedure. If DTC does not reset, diagnose malfunction by symptom. See TROUBLE SHOOTING - NO CODES article for diagnosis by symptoms. After performing necessary repairs, go to next step.
  6. Rerun test situations which set DTC(s). Retrieve codes and confirm DTC P0000 (System Normal) is detected. Clear DTC(s) from PCM and TCM memory. See CLEARING CODESΒ .
MULTIPLE DTC PRIORITY IDENTIFICATION (1)

Priority DTC
1 P0100, P0110, P0115, P0120, P0125, P0180, P0325, P0335, P0340, P0500, P0605, P1320, P1335, P1336, P1400 & P1706
2 P0105, P0130, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0139, P0140, P0141, P0150, P0151, P0152, P0153, P0154, P0155, P0443, P0446, P0450, P0510, P0705, P0710, P0720, P0725, P0740, P0744, P0745, P0750, P0755, P1105, P1401, P1444, P1446, P1447, P1448, P1490, P1491, P1492, P1493, P1705 & P1760
3 P0130, P0150, P0171, P0172, P0174, P0175, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0400, P0402, P0420, P0440, P0505, P0600, P0731, P0732, P0734, P1320 & P1440
(1) DTCs do not apply to all models. See appropriate DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION table for DTC description and equivalent MIL code.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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