I have Chrysler 300 touring AWD 2008 with 158000kms on it .Its showing all 4 oxygen sensor are bad at same time.I have visited 3 car repair shops they tried to reset the error codes but when they start the engine it shows the same codes at the same time when we start the car.Check engine light is not going off not for a second after clearing the codes.
So the garage checked the gounds and fuses but they did not check for oxygen sensor activity - they need to check with a DVOM to see if your O2 sensor are working for sure.
@manpreet
The light will not turn off until the issue is fixed. Or perhaps it's not letting you clear the code due to it being a smog code. Certain codes related to smog (such as the O2 sensor) cannot be cleared manually until a proper drive cycle is performed. The ECU will clear it itself once it sees the problem is fixed.
I have never seen a car that will not even allow you to clear a code until it is fixed not to say it’s impossible but that wouldn’t make as much sense in this scenario and if it’s an emissions state the code has to be able to be physically cleared in order to complete the drive cycle and check for any previous codes.
@r4nier
It is possible, at least on my BMW. I had a rich running code one time and the ECU didn't allow me to clear it manually. The ECU needed to see 3 successful drive cycles with the engine running normally before the code was automatically cleared. I belive it's done on purpose on newer cars so you cannot clear the code right before a smog check (maybe it's a California thing). It's happened on my brother's Dodge too in regards to downstream O2 sensor. It's a real thing...but perhaps may not apply to the original post.
Learn something new every day
I again went to the garage the guy changed 1 o2 sensor after that he checked the readings all the sensors were working but the light doesn’t turns off
Have you already replaced the sensors? Very odd for all four to throw hard faults at the same time. It sounds like possibly and ecm or electrical concern maybe a bad ground
I have not replaced the sensors yet because the light is not going off not even for a second its doubtful yesterday i have visited garage they have checked all the grounds and fuses
He also checked bank 1 and 2 sensor and told me that its getting low voltage.But he was unable to find the exact problem
Ya it definitely sounds like it’s more likely in the ecm due to the fact that it’s multiple sensors triggering automatically. Generally from the ecm to each sensor is an independent wire so the common denominator if the grounds are definitely all good is the ecm
Found this on the 300 forum about your issue...
https://www.300cforums.com/threads/o2-sensor-problem.50341/