Protege & Protege5

Remove IAT sensor. Using ohmmeter, measure resistance between IAT sensor terminals "A" and "B". See Fig 1 . See IAT SENSOR RESISTANCE (PROTEGE & PROTEGE5)  table. If not as specified, replace IAT sensor. If resistance readings are as specified, check for open in Blue/White wire between IAT sensor harness connector terminal "A" and PCM harness connector terminal No. 39 or Orange wire between IAT sensor harness connector terminal "B" and PCM harness connector terminal No. 91. Check for short to ground in Blue/White wire between IAT sensor harness connector terminal "A" and PCM harness connector terminal No. 39. Repair or replace wiring harness as necessary.

Fig 1: Identifying IAT Sensor Terminals (Miata, Protege & Protege5)

Courtesy of MAZDA MOTORS CORP.