Mass Airflow Sensor: Miata
- Visually check Mass Airflow (MAF) sensor for cracks or damage. If any damage is present, replace MAF sensor. If MAF sensor is okay, go to next step.
- Voltage Inspection
Turn ignition on. Using DVOM, measure voltage at PCM 31-pin harness connector terminal No. 4X (Pink wire). See Figure. See MAF SENSOR VOLTAGE SPECIFICATIONS table. If voltage reading is not as specified, check for open or short circuit: - Open Circuit Inspection
Disconnect PCM 31-pin harness connector. Check for continuity between following terminals:- MAF circuit - MAF sensor 3-pin harness connector terminal "B" and PCM 31-pin harness connector terminal No. 4X.
- Power circuit - MAF sensor 3-pin harness connector terminal "C" and main relay 4-pin harness connector terminal "D" through common connector.
- GND circuit - MAF sensor 3-pin harness connector terminal "A" and PCM 31-pin harness connector terminal No. 4A through common connector.
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.
- Short Circuit Inspection
Check for continuity between following:- MAF sensor 3-pin harness connector terminal "B" and PCM 31-pin harness connector terminal No. 4X (Pink wire) to ground.
- MAF sensor 3-pin harness connector terminal "C" and main relay 4-pin harness connector terminal "D" (White/Red wire) to ground.
If continuity is present, repair short circuit in suspect wire or replace wire harness. If open or short circuit is not present, replace MAF sensor.
MAF SENSOR VOLTAGE SPECIFICATIONS
| Model/Condition | Volts | |
|---|---|---|
| Miata, Protege & Protege5 | ||
| Ignition On | 0.9-2.0 | |
| Idle | 1.7-2.4 | |
| MPV | ||
| Ignition On | 0-0.1 | |
| Idle | 0.5-0.8 | |