melinataylor1

GX oxygen sensor heater failure

Alright, GX gurus, I'm pulling my hair out! My 2017 Lexus GX with a gasoline engine is throwing a check engine light and the code reader says it's an oxygen sensor heater failure. I'm also seeing higher fuel consumption, which is a pain. I suspect it's a bad connection somewhere since I haven't seen any obvious damage. Anyone else run into this?

A 2017 Lexus GX was experiencing a check engine light and increased fuel consumption, with a diagnostic code indicating an oxygen sensor heater failure. The suspected cause was a bad connection, possibly due to corrosion. The solution involved checking and cleaning the wiring harness and connector, and ultimately replacing the faulty oxygen sensor, which resolved the issue and restored normal fuel economy.

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4 comment(s)

I had a similar issue with my GX. Same symptoms: check engine light, fuel economy tanked, and the code pointed to the O2 sensor heater circuit. I'd suggest checking the wiring harness and connector for the sensor. Corrosion or a loose connection can definitely cause that heater circuit to fail. Did you try testing the sensor itself?

Good call on the wiring harness, I'll give that a closer look. When you say 'testing the sensor,' what exactly did you do? I have a multimeter, but I'm not entirely sure what readings I should be looking for to confirm a faulty heater element. Any tips?

Yeah, the heater element has a specific resistance range. You can disconnect the sensor and use your multimeter to check the resistance across the heater element terminals. If it's way out of spec (usually open circuit), the heater's probably shot. Honestly, if you're not comfortable with that, a shop can diagnose it pretty quickly. It could be as simple as a bad sensor, or something upstream causing the issue.

Thanks a bunch for the advice! It turns out the connector was indeed corroded. Cleaned it up, but the sensor was still dead. Ended up replacing it – cost me about 95€ with a new Bosch sensor. Problem solved, check engine light is gone, and fuel economy is back to normal. I'm grateful for your help!

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LEXUS

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