Just had my 2001 MPV (18000 miles) to shop with CEL showing. Paid $140 for OBD check. Fault code was P0031 - Oxygen sensor. "Found waveform to be incorrect at times All wiring found to be good at this time. Intermittent internal failure. Scan system needs O2 sensor."

Replacemnt part and installation is $240. Is this a common failure and should I have to pay for it? I would assume that a sensor like this should have a longer life than 5 years and <20K miles. Does this mean it was a poor quality sensor to start with and should Mazda replace it free?

Anyone with adice or experince or suggestions.

 

P0031 is indicating a fault in the heater system in the oxygen sensor. The heater is designed to heat the sensor to an operating temperature quickly so that emission levels can be lowered. $140 is very steep in my area for diagonstic and would probably be half that but you live in Venice so that is probably the going rate. The sensor in question is called an Oxygen Sensor and they do sometimes have a faster failure rate. This sensor is in the exhaust pipe so it fluctuates in temp from cold night temps to 2000'F when heater works and engine is running. Do that twice a day and see how long you would last. Brutal conditions for a sensor and they do fail. Mazda will replace during the normal warranty but after that if is your bill.

 

To keep geeting a oxygen sensors trouble, the best way to do is to replace it every 30,000 to 50,00 miles. Replacing your oxygen sensor at regular intervals will surely allow you to save fuel efficiently and other expenses.