Oxygen Sensor: Testing and Inspection

1990 Mazda 626 L4-2184cc 2.2L SOHC F2SECTION Testing and Inspection

OUTPUT VOLTAGE

Output Voltage Check:






1. Warm engine to operating temperature and run at idle.
2. Disconnect oxygen sensor connector. Connect voltmeter between sensor and ground.
3. Run engine at 4500 rpm until meter indicates approximately 0.7V.
4. Increase and decrease engine speed suddenly several times. Verify that meter reads 0.5 - 1.0V when speed is increased and 0 - 0.4V when speed is decreased.
5. If not as specified, replace sensor.

SENSITIVITY

Sensitivity Check:






NOTE: This test requires use of Mazda Self-Diagnosis Checker (SST #49 H018 9A1) or suitable aftermarket "Scan" tool.

1. Warm engine to operating temperature.
2. Connect test tool to check connector.
3. Increase engine speed to between 2000 and 3000 rpm. Verify that monitor lamp flashes more than 8 times during a 10 second period.
4. If not as specified, replace sensor.
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.