Nissan Repair: Exterra04 sensors-service light on, exhaust gases, oxygen sensor

Question
Auto Zone hooked up a diagnostic tool to my exterra 2004 SUV.
"Oxygen Sensor Low, Voltage Bank 2 S1. Knock Sensor 1 circuit Bank 1" showed up.
What does all this mean and how much should I be paying for replacement and repair?
Thank you for sharing your knowledge.

Answer
Hello DA

The oxygen sensor detects fuel to air mix ratios and tells the computer to make it richer or leaner depending on the exhaust gases. Bank 2 means the driver's side of the car, or left side as you look at the front of the engine.

The knock sensor detects engine pinging and adjusts timing automatically to compensate.

All these sensors work off of Millivolts (MV) and report back to the car's computer, or ECU. If anything is out of balance or parameters, it will kick the engine light on, and then a diagnostic is done, such as the one you just did. Whatever sensor is giving the wrong reading will show.

Although the O2 sensor and Knock Sensor are not a matter of life or death, it should be replaced. Costs vary, but I say expect a couple hundred dollars at the most for the replacement.

Hope this helps
aloha
calvin