LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mazda >> 2002 >> MPV LX >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Engine Sensors & Switches >> Heated Oxygen Sensor >> MPV
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Heated Oxygen Sensor: MPV

  1. Voltage Inspection

    Warm engine to normal operating temperature. Turn ignition off. Disconnect suspect HO2S connector. Connect voltmeter to HO2S terminals. See HO2S TERMINAL IDENTIFICATION (MPV)  table. Start engine. Raise engine speed to 3000 RPM until sensor voltage varies between zero and one volt. Allow engine to idle. Accelerate engine several times. Voltage should be .5-1.0 volt when accelerating, 0-.5 volt when decelerating. If sensor voltage is as specified but PID value or PCM voltages are not within specification, check for open or short circuit. Disconnect PCM harness connector. Connect 104-Pin Breakout Box (49-UN01-130) to PCM wire harness connector only. See Figure . Go to steps  2 and  3 . If sensor voltage is not as specified, replace HO2S.
    HO2S TERMINAL IDENTIFICATION (MPV)

    Application Terminals
    Left Front A (+), B (-)
    Left Rear A (+), B (-)
    Right Front A (+), B (-)
    Right Rear A (+), B (-)

  2. Open Circuit Inspection

    Check for continuity between following terminals:
    • Right front HO2S harness connector terminal "A" and breakout box terminal No. 60.
    • Right front HO2S harness connector terminal "B" and breakout box terminal No. 91
    • Right rear HO2S harness connector terminal "A" and breakout box terminal No. 35
    • Right rear HO2S harness connector terminal "B" and breakout box terminal No. 91.
    • Left front HO2S harness connector terminal "A" and breakout box terminal No. 87.
    • Left front HO2S harness connector terminal "B" and breakout box terminal No. 91.
    • Left rear HO2S harness connector terminal "A" and breakout box terminal No. 61.
    • Left rear HO2S harness connector terminal "B" and breakout box terminal No. 91.

    If continuity is present, go to next step. If continuity is not present, repair open circuit or replace wire harness as necessary. See WIRING DIAGRAMS article.

  3. Short Circuit Inspection

    Check for continuity between following terminals:
    • Right front HO2S harness connector terminal "A" and ground.
    • Right front HO2S harness connector terminal "A" and power.
    • Right front HO2S harness connector terminal "B" and power.
    • Right rear HO2S harness connector terminal "A" and ground
    • Right rear HO2S harness connector terminal "A" and power.
    • Right rear HO2S harness connector terminal "B" and power.
    • Left front HO2S harness connector terminal "A" and ground.
    • Left front HO2S harness connector terminal "A" and power.
    • Left front HO2S harness connector terminal "B" and power.
    • Left rear HO2S harness connector terminal "A" and ground.
    • Left rear HO2S harness connector terminal "A" and power.
    • Left rear HO2S harness connector terminal "B" and power.

    If continuity is not present, go to next step. If continuity is present, repair short circuit or replace wire harness as necessary.

  4. HO2S Heater Resistance Inspection

    Allow sensor to cool to room temperature. Disconnect suspect HO2S connector. Using ohmmeter, measure resistance between HO2S connector terminals "C" and "D". See HO2S HEATER TERMINAL RESISTANCE SPECIFICATION (MPV)  table. If resistance is not as specified, replace HO2S. If HO2S is okay but PID values are out of specification, check for open or short circuit. Connect 104-Pin Breakout Box (49-UN01-130) to PCM harness connector only. See Figure . Go to steps  5 and  6 .
    HO2S HEATER TERMINAL RESISTANCE SPECIFICATION (MPV)

    Application Terminals Ohms
    Left Front C & D 5.0-6.8
    Right Front C & D 5.0-6.8
    Left Rear C & D 14.1-18.9
    Right Rear C & D 14.1-18.9

  5. Open Circuit Inspection

    Check for continuity between following terminals:
    • Right front HO2S harness connector terminal "C" and power.
    • Right front HO2S harness connector terminal "D" and breakout box terminal No. 93.
    • Right rear HO2S harness connector terminal "C" and power.
    • Right rear HO2S harness connector terminal "D" and breakout box terminal No. 95.
    • Left front HO2S harness connector terminal "C" and power.
    • Left front HO2S harness connector terminal "D" and breakout box terminal No. 94.
    • Left rear HO2S harness connector terminal "C" and power.
    • Left rear HO2S harness connector terminal "D" and breakout box terminal No. 96.

    If continuity is not present, repair open circuit or replace wire harness as necessary. See WIRING DIAGRAMS article.

  6. Short Circuit Inspection

    Check for continuity between following terminals:
    • Right front HO2S harness connector terminal "C" and ground.
    • Right front HO2S harness connector terminal "D" and ground.
    • Right front HO2S harness connector terminal "D" and power.
    • Right rear HO2S harness connector terminal "C" and ground.
    • Right rear HO2S harness connector terminal "D" and ground.
    • Right rear HO2S harness connector terminal "D" and power.
    • Left front HO2S harness connector terminal "C" and ground.
    • Left front HO2S harness connector terminal "D" and ground.
    • Left front HO2S harness connector terminal "D" and power.
    • Left rear HO2S harness connector terminal "C" and ground.
    • Left rear HO2S harness connector terminal "D" and ground.
    • Left rear HO2S harness connector terminal "D" and power.

    If continuity is present, repair short circuit or replace wire harness as necessary.

scientia non olet · About LEMON Manuals