Idle Air Control Valve: Miata

2008 Mazda 6 s Sport, 4D Hatchback, StandardSECTION Miata
WARNING: This page is about a different car, the 2003 Mazda Protege5, 2003 Mazda Protege, 2003 Mazda MX-5 Miata, 2003 Mazda MPV, and 2003 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

  1. Resistance Inspection

    Disconnect IAC valve 2-pin harness connector. See IAC VALVE LOCATIONΒ  table. Using an ohmmeter, measure resistance between IAC valve terminals. See IAC VALVE RESISTANCE SPECIFICATIONSΒ  table. If IAC valve is okay, check for open or short circuit. Go to next step. If resistance reading is not within specification, replace IAC valve.
  2. Open Circuit Inspection

    Disconnect PCM 17-pin harness connector. Check for continuity between following terminals:
    • Power circuit - IAC valve harness connector terminal "A" and PCM 17-pin harness connector terminal No. 2P (Orange wire).
    • GND circuit - IAC valve harness connector terminal "B" and PCM 17-pin harness connector terminal No. 2Q (Violet/Red wire).

    If continuity is present, go to next step. If continuity is not present, repair open circuit in suspect wire or replace wire harness. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS.

  3. Short Circuit Inspection

    Check for continuity in Orange wire between IAC valve harness connector terminal "A" and PCM 17-pin harness connector terminal No. 2P to ground. If continuity is present, repair short circuit in Orange wire between PCM 17-pin harness connector No. 2P and IAC valve harness connector terminal "A".
IAC VALVE LOCATION

Application Location
Miata On Bottom Of Throttle Body
MPV, Protege & Protege5 On Top Of Throttle Body
IAC VALVE RESISTANCE SPECIFICATIONS

Application Ohms
Miata & MPV (1) 8.7-10.5
Protege & Protege5 (2) 7.7-9.3
(1) With IAC valve temperature at 75Β°F (24)Β°C.
(2) With IAC valve temperature at 73Β°F (23)Β°C.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

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.