P0037

Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2

The nice young man at Advanced Auto down the street used his nifty OBDII scanner to read the code which caused the Check Engine light that short circuited our plans to drive the Emperor to Florida. The Miata is an inline 4 cylinder engine, so Bank 1 is the only possible option, Sensor 2 meant it is the downstream sensor, AKA the one after the catalytic converter.

I searched the Miata.net Forums for what this all meant for me. Sensor 2 just monitors the effectiveness of the cat and if you live in a non-Smog Check state it is not a real problem because the data is not used in changing any ignition parameters. You could just not fix it and leave the Check Engine light illuminated all the time, but the downside to that is you could throw another possibly important code and not know it. I’m going to be a good boy and fix it.

From reading the forum it seems like I might even be able to do the repair myself, so I ordered a new sensor from Parts Geek, $80 plus $9 for shipping. According to hive memory of the forum I’ll also need a O2 Sensor wrench to get this thing out, so I ordered one of them from Harbor Freight, $6 plus $7 for shipping.

Why, oh, why would I spend more for shipping than I did for the tool? The closest Harbor Freight is in Augusta and it would cost more in gas and aggravation to go get it when the postman will bring it right to my door. I suppose I could have borrowed one from a MMC member, but this way I’ll have the wrench when I need to replace the front sensor. Which would invariably have happened right after I returned the borrowed wrench.