Protege & Protege5
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2002 Mazda Protege5, 2002 Mazda Protege, 2002 Mazda Millenia, 2002 Mazda MX-5 Miata, and 2002 Mazda MPV. However, it is still accessible from the selected car via links, so may be relevant.
- Voltage Inspection
Warm engine to normal operating temperature. Allow engine to idle. Disconnect HO2S connector (front or rear). Connect DVOM test leads to HO2S terminals "A" and "B". Increase engine RPM to 3000 until voltmeter reads about 0.5-0.7 volts. While increasing or decreasing engine speed suddenly, ensure voltmeter reading also changes. See HO2S VOLTAGE (PROTEGE & PROTEGE5) table. If voltmeter reading changes, but PID value or PCM terminal No. 60 (front HO2S), 35 (rear HO2S) voltages are out of specification, check for open or short circuit between PCM and HO2S. Go to next step. If voltmeter reading does not change with engine speed, replace HO2S.HO2S VOLTAGE (PROTEGE & PROTEGE5)Application Volts Acceleration 0.5-1.0 Deceleration 0-0.5 - Open Circuit Inspection
Connect 104-Pin Breakout Box (49-UN01-130) between PCM and harness connector. See Figure . Check for continuity between following terminals:- HO2S harness connector terminal "A" and breakout box terminal No. 60 (front sensor) or No. 35 (rear sensor).
- HO2S harness connector terminal "B" and breakout box terminal No. 91.
If continuity is not present, repair wiring or replace wire harness as necessary. See WIRING DIAGRAMS article. If continuity is present, go to next step.
- Short Circuit Inspection
Check for continuity between HO2S harness connector terminal "A" and breakout box terminal No. 60 (front sensor) or No. 35 (rear sensor) to ground. If continuity is present, repair wiring or replace wire harness as necessary. If continuity is not present, go to next step. - HO2S Heater Resistance Inspection
Allow sensor to cool to room temperature. Disconnect front and rear HO2S connector. Measure resistance between front HO2S terminals "C" and "D". See Fig 1 . Resistance should be about 5.6 ohms at 68°F (20°C). Measure resistance between rear HO2S terminals "C" and "D". See Fig 1 . Resistance should be about 15.7 ohms. If resistance is not as specified, replace appropriate HO2S. If resistance is as specified but PID value or PCM terminal No. 93 or 94 voltage is out of specification, check for open or short circuit. Go to next step. - Open Circuit Inspection
Connect 104-Pin Breakout Box (49-UN01-130) between PCM and harness connector. See Figure . Check for continuity between following terminals:- HO2S harness connector terminal "C" and ignition switch terminal "IG1" (Blue wire) through common connector. See Fig 2 .
- HO2S harness connector terminal "D" and breakout box terminal No. 94 (front sensor) or No. 93 (rear sensor).
If continuity is not present, repair open in wiring or replace wire harness as necessary. See WIRING DIAGRAMS article. If open circuit is not found, go to next step.
- Short Circuit Inspection
Check for short circuit between following terminals:- HO2S harness connector terminal "C" and ignition switch terminal "IG1" (Blue wire) through common connector to ground. See Fig 2 . See WIRING DIAGRAMS article.
- HO2S harness connector terminal "D" and breakout box terminal No. 94 (front sensor) or No. 93 (rear sensor) to ground.
If continuity is present, repair short in wiring or replace harness as necessary. If short circuit is not found, replace HO2S.