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.
Circuit Description
Heated oxygen sensors located on each exhaust manifold monitor exhaust gas oxygen content and deliver input signals to ECM. Heated oxygen sensor on driver's side exhaust manifold may be referred to as bank No. 1 sensor No. 1 and heated oxygen sensor on passenger's side exhaust manifold may be referred to as bank No. 2 sensor No. 1. ECM uses input signals to determine fuel injection system operation. DTC is set when heated oxygen sensor does not output a rich condition (output voltage equal to or more than .45 volt) even once after engine is started with engine at normal operating temperature, engine speed of 1400 RPM or more and with vehicle speed of 25-62 MPH for at least 65 seconds. Possible causes are:
- Heated oxygen sensor circuit is open or shorted.
- Defective heated oxygen sensor.
- Air induction system malfunction.
- Improper fuel pressure.
- Defective fuel injector.
- Exhaust system leak.
- Vehicle has run out of fuel.
- Defective ECM.
- Defective Positive Crankcase Ventilation (PCV) valve piping.
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.