Diagnostic Procedure
- Turn ignition off. Connect New Generation Star (NGS) tester or equivalent to OBD-II Data Link Connector-2 (DLC-2). See Figure. Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check for service bulletins and/or other line of repair information related to this DTC. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 5. If repair information is not available, go to next step.
- Turn ignition off. Disconnect IAT sensor 2-pin harness connector. See Fig 1. Check for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary and go to step 5.
- With IAT sensor harness connector disconnected, measure resistance between IAT sensor connector terminals "A" and "B" (component side). Resistance should be 2.21-2.69 k/ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace IAT sensor. For circuit identification, see MIATA
in WIRING DIAGRAMS article. After repair, go to step 5.
- Leave IAT sensor harness connector disconnected and disconnect PCM 31-pin harness connector. See Fig 1. Check terminals "4N" and "4O" for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary and go to next step.
- Return vehicle to original condition. Using NGS tester or equivalent, clear DTCs from PCM memory. Start engine and let it idle until it reaches normal operation temperature. Monitor for DTCs. If same DTC P0111 is present, replace PCM. For PCM removal and installation, see POWERTRAIN CONTROL MODULE
under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. If any other DTC is present, follow appropriate DTC diagnostic procedure.
Courtesy of MAZDA MOTORS CORP.