Mar 10, 2013 · The only way an O2 sensor throws a code is if the heater circuit is bad. The ECU doesn't know whether it's reading incorrectly or not - it only knows if the sensor itself is …

Feb 19, 2009 · First there is a difference between a O2 sensor and a more commonly used HO2 sensor. It is almost impossible for a failing primary HO2 not to cause an ECU generated DTC.

Dec 9, 2012 · My question is can an O2 sensor go bad without giving a code? This is what was happening.Check engine light comes on. 8 codes,O2 sensor bank 2,all kinds of misfires,fuel …

Oct 5, 2025 · Can an O2 sensor be bad without code? Yes, an oxygen (O2) sensor can be bad without immediately triggering a Check Engine Light (CEL) or setting a specific Diagnostic …

Aug 19, 2022 · When you get an oxygen sensor code, that does NOT automatically mean the sensor is bad. In fact, 80% of all oxygen sensors returned under warranty are perfectly good.

Jan 31, 2015 · I would not think that the O2 sensors are bad especially if you are not throwing codes. However, perhaps your engine is running cold or the engine temperature sensor is bad.

May 23, 2025 · There are a few symptoms that can point to a bad oxygen sensor, but the best way to know for sure is by using an OBD-II scanner or letting a professional mechanic …

Nov 11, 2025 · Learn the main symptoms of a bad oxygen (o2) sensor and find out what you can expect to pay for a replacement.

Jan 30, 2026 · The most effective way to test an O2 sensor is by using an OBD2 scanner with a “Data Stream” or “Live Data” function. This allows you to see real-time voltage changes rather …

Dec 18, 2011 · Can an O2 sensor be bad and NOT throw a code? I am still having a rough idle and unless it's me, I think the Jeep is running below its potential. I wish someone close to me …