MX-5 Miata Mazdaspeed L4-1.8L DOHC Turbo (2004)
Oxygen Sensor: Component Tests and General Diagnostics
Heated Oxygen Sensor (HO2S) Heater Inspection
HEATED OXYGEN SENSOR (HO2S) HEATER INSPECTION
Inspection of Resistance
NOTE: Perform the following test only when directed.
1. Disconnect the HO2S connector.
2. Measure the resistance between HO2S terminals C and D using an ohmmeter.
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If not as specified, replace the HO2S.
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If HO2S heater is okay, but PID value is out of specification, perform the "Circuit Open/Short Inspection".
Specification
Approx. 5.6 ohms (Front)
Approx. 15.7 ohms (Rear)
3. Reconnect the HO2S connector.
Circuit Open/Short Inspection
Open circuit
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If there is no continuity, the circuit is open. Repair or replace the harness.
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GND circuit (HO2S connector D and PCM connector terminal 3J through common connector (Front).)
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Power circuit (HO2S connector terminal C and ignition switch (IG1) circuit through common connector (Front).)
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GND circuit (HO2S connector terminal D and PCM connector terminal 3P (Rear).)
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Power circuit (HO2S connector terminal C and ignition switch (IG1) circuit through common connector (Rear).)
Short circuit
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If there is continuity, the circuit is shorted. Repair or replace the harness.
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HO2S connector terminal C and ignition switch (IG1) through common connector to GND (Front).
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HO2S connector terminal D and PCM connector terminal 3J through common connector to GND (Front).
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HO2S connector terminal D and PCM connector terminal 3P to GND (Rear).
Heated Oxygen Sensor Inspection
HEATED OXYGEN SENSOR (HO2S) INSPECTION
Inspection of Voltage
