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
The oxygen sensor is heated to control operating temperature of the sensor. The heating element receives voltage from terminal No. 87 of the fuel pump relay and is heated as long as the fuel pump operates.
The oxygen sensor system uses a malfunction indicator, which is located on the instrument panel. The malfunction indicator light will come on if a malfunction is present in the oxygen sensor circuit. The oxygen sensor malfunction indicator light receives voltage from the CIS-E control unit.
There are 2 versions of the malfunction light:
- Version 1: Lights up briefly when starting the engine.
- Version 2: Lights up as soon as the ignition is switched on and goes out when the engine is started. If an oxygen sensor failure is present, the malfunction indicator lights up after about 5 minutes of engine operation.
Use the Manual With the Right Hardware
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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.