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.
Set Condition
The Powertrain Control Module (PCM) detects that the O2 Sensor Heater element resistance is above 4640 Ohms for 4 tests during this ignition cycle. The PCM cannot directly measure the heater resistance, therefore the heater rationality is determined as follows: A 1 mA current is pulsed through the O2 Sensor circuit and the voltage across the sensor is measured. The heater health is inferred by this measurement. To avoid overheating and damaging the O2 Sensor, the resistance can only be measured periodically and during fuel cutoff. Two trip fault. Three good trips to turn off the MIL.
NO RELATED
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.