2005 Cadillac SRX O2 sensor

Diagnostic fault codes never say to replace parts or that they're defective. They only indicate the circuit or system that needs further diagnosis. The sensor itself is only the cause of the code about half of the time, in fact, a lot of codes don't even make reference to a particular sensor.

There are dozens of fault codes related to the oxygen sensors and they all mean different things. Some codes are just the result of what a properly-working sensor is reporting. Knowing the exact code number is helpful in determining how the problem should be diagnosed.