1998 Mazda B2500 SX, AutomaticFACTORY OEM SERVICE PROCEDURE

Idle Air Control (IAC) Solenoid

  1. If IAC solenoid circuit is open or shorted, a Diagnostic Trouble Code (DTC) should set. See TESTS W/CODES article. If any DTCs are present, repair as necessary. If no DTCs are present, go to next step.
  2. To check IAC solenoid, connect New Generation Star (49 T088 0A0) scan tool to Data Link Connector (DLC) 2. DLC is located under left side of instrument panel, right of steering column. Turn ignition on. Using scan tool, access DIAGNOSTIC DATA LINK menu, and select PCM. Highlight and select PID/DATA MONITOR AND RECORD.
  3. Start engine and operate at idle. Using scan tool, access IAC PID and record value while operating vehicle under specified condition. See appropriate PID value chart in PIN VOLTAGE/PID VALUE CHARTS article. If IAC PID value is not as specified, go to next step.
  4. Turn ignition off. Disconnect IAC solenoid connector. Using ohmmeter, measure resistance between IAC solenoid terminals. A diode is located in solenoid; connect ohmmeter positive test lead to VPWR terminal (Red wire) and negative lead to IAC SIG terminal (White/Light Blue wire). Resistance should be 6-13 ohms at 68°F (20°C). If resistance is not as specified, replace IAC solenoid.
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When to See a Mechanic

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

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