O2 Sensor codes rarely mean that the O2 Sensors are defective. Most of the time, the O2 sensors are reporting a problem that is occuring somewhere else in the system. If your are getting a code that says "O2 sensor lean" that means that someting on that side of the engine is causing that side to be running lean. This is usually caused by a vacuum leak, but may also be caused by bad injectors or low fuel pressure. If BOTH sides are reporting lean O2 Sensor codes at the same time, it is something wrong that affects both sides of the engine including vacuum leaks in the main hoses tied into the intake manifold including the PCV hose and the Brake Booster Vacuum hose or the brake booster itself, or the Mass Airflow Sensor. Defective Engine Coolant Temperature sensors can also cause these codes. If the code you are getting is a "O2 Sensor Rich" code, it is caused by something that is making the engine run rich. This could be a sticking injector, a failed Fuel Pressure Regulator, or an O2 Sensor circuit that is shorted to voltage, or a malfunctioning Mass Airflow Sensor.
If you want to save a lot of money and frustration, learn this: Fault codes NEVER tell you what parts to replace. Fault codes only tell you which of the many systems monitored by the computer are operating outside their expected ranges or "Window of Operation". It is up to the person diagnosing the vehicle to test the system that is reporting the malfunction and determine the cause of the failure and repair as necessary.
P.S. O2 Sensors are kind-of like a report card for your engine. If the O2 Sensors are happy, that means that everyone involved with internal combustion is happy. If the O2 Sensors are not happy, it is because somebody in the chain of command is not doing his/her job..The O2 Sensor's job is to rat them out! :)
×
1,092 views
Usually answered in minutes!
×