Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Oxygen Sensor
| Circuit | PCM Pin | BOB Pin | Wire Color |
|---|---|---|---|
| O2S | 2D | 29 | BLK |
1) Warm engine to operating temperature, and let idle. Unplug O2S. Measure voltage between O2S connector (sensor side) and ground. With engine at idle, voltage should fluctuate between 0.2-0.8 volt.
2) Increase and decrease engine speed while reading voltmeter. When engine speed is decreasing, voltage should decrease. When engine speed is increasing, voltage should increase. If voltage is within specification, go to next step. If voltage is not within specification, replace O2S.
3) With ignition off, install BOB. Leave PCM disconnected. Unplug O2S connector. Measure continuity between O2S test pin and O2S connector wire. If continuity exists, O2S circuit is okay. Return to QUICK TESTS if sent here from there. If not sent here from QUICK TESTS, replace PCM. If voltage is not as specified, repair VMREF wire to VAF. If continuity does not exist, service PCM sensor wire to PCM.
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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.
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