Engine Controls - System/component Tests - 2.5L: Diagnosis Mazda Millenia I

(Using New Generation Star (NGS) Scan Tool)

1. Warm engine to normal operating temperature. Connect NGS scan tool to Data Link Connector (DLC) 2. DLC 2 is located under left side of instrument panel, right of steering column. Using scan tool, access DIAGNOSTIC DATA LINK menu, and select PCM. Highlight and select PID/DATA MONITOR AND RECORD.
2. Turn ignition on. Select HO2S Parameter Identification (PID) to be checked. See «HO2S PID IDENTIFICATION»(ref-18677-S23810362992000123000000) table. Voltage should be.5-1.0 volt under acceleration and 0-.5 volt under deceleration. If voltage is not as specified, check wiring harness and connector between ECM and HO2S. Also check intake manifold system, fuel system and self-diagnostic system. Repair as necessary. If no problems are found, replace HO2S.
3. 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". (Схема №4) Resistance should be about 6 ohms with sensor temperature at 68°F (20°C). If resistance is not as specified, replace HO2S.

HO2S PID IDENTIFICATION

Using New Generation Star (NGS) Scan Tool

1. Visually check MAF sensor for cracks or damage. If any damage is present, replace MAF sensor. If no damage is present, turn off all accessories. Connect New Generation Star (NGS) scan tool to Data Link Connector (DLC) 2. DLC 2 is located under left side of instrument panel, right of steering column. Turn ignition on.
2. Using scan tool, select PID/DATA MONITOR AND RECORD function. Select MAF V PID and record value while operating vehicle under specified conditions. See «MASS AIRFLOW (MAF) SENSOR VOLTAGE»(ref-18677-S20962075792000123000000) table. If voltage is not as specified, check continuity of each circuit between MAF sensor and ECM/PCM. See appropriate wiring diagram in «WIRING DIAGRAMS - 2.5L»(/mazda/millenia/i-1994-2000/remont/wiring-diagrams-engine-performance/#wiring-diagrams-25l) article. Repair as necessary. If continuity exists in all circuits, replace MAF sensor.

MASS AIRFLOW (MAF) SENSOR VOLTAGE

System Inspection

Purge system operation takes place when vehicle is accelerating in gear (off idle), engine is at operating temperature and oxygen sensor is functioning normally.

Verify that engine coolant temperature is less than 68°F (20°C). Start engine and operate at idle. Remove Positive Crankcase Ventilation (PCV) valve, with hose attached, from valve cover. Block PCV valve opening and check for vacuum. If no vacuum is felt, check for collapsed or blocked PCV valve hose. Repair as necessary. If hose is okay, replace PCV valve.

See also:
• WIRING DIAGRAMS - 2.5L