Heated Oxygen Sensor (Ho2S): Miata
WARNING: This page is about a different car, the 2001 Mazda Protege, 2001 Mazda Millenia, 2001 Mazda MX-5 Miata, 2001 Mazda MPV, and 2001 Mazda 626. However, it is still accessible from the selected car via links, so may be relevant.
- Warm engine to normal operating temperature. Connect NGS scan tool to DLC-2. DLC-2 is located under left side of instrument panel, behind fuse block cover. Using scan tool, access DIAGNOSTIC DATA LINK menu, and select PCM. Highlight and select PID/DATA MONITOR AND RECORD.
- Turn ignition on. Select FHO2S PID for front sensor or RHO2S PID for rear sensor. See HO2S VOLTAGE (MIATA) table. If voltage is not as specified, check wiring harness between PCM and HO2S. Also check intake manifold system, fuel system and self-diagnostic system. Repair as necessary. If problems are not present, replace HO2S.
- To test HO2S heating element, allow sensor to cool to room temperature. Disconnect HO2S connector. Using ohmmeter, measure resistance between sensor terminals "C" and "D". See Fig 1 . Resistance should be about 16 ohms with sensor temperature at 68°F (20°C). If resistance is not as specified, replace HO2S.
HO2S VOLTAGE (MIATA)
| Application | Volts | |
|---|---|---|
| PCM Terminal 3V (Rear Sensor) | ||
| Acceleration | 0.5-1.0 | |
| Deceleration | 0-0.5 | |
| Idle | 0-0.5 | |
| PCM Terminal 1U (Front Sensor) | ||
| Acceleration | 0.5-1.0 | |
| Deceleration | 0-0.5 | |
| Idle | 0-1.0 | |