2003 Mazda MPV Trouble Code P0037

ANOTHERSPIFF

MEMBER
2003 MAZDA MPV
6 CYL
2WD
AUTOMATIC
66,000 MILES

Last week our check engine light came on. Today we took it to a dealer and he hooked it up and told us we had a trouble code P0037, and O2 sensor, bank 1 sensor 2. He went ahead and reset the code, told us to come back if it lit back up, in case it was just a fluke.
He quoted us around $370 if it needs to be replaced.

The light came back on within half an hour. I didn't take it back, I wanted to do some research first. I called autozone and they said it was possibly my catalytic converter, but when I read up on that it talks about obvious loss of power and a rotten egg, sulphur- like smell. I really hope this isn't the case.

I have noticed absolutely NO change in the cars performance, although when the light is on I could smell the emissions from the exhaust. When he reset the code, I didn't notice the smell until the light came back on again. It isn't strong or overpowering, and I really only notice it when I'm idling with a window down. It doesn't smell like sulphur at all.

What I'd like to know is if it is likely that it is the sensor, or is the sensor simply doing it's job and indicating a problem elsewhere? If it isn't the sensor where should we look? If it IS the sensor, how would we go about replacing that ourselves (if it is even possible)?

1 Reply

MHPAUTOS

MECHANIC
31,937 POSTS

Hi there,

A bit of background info,

What does an Oxygen Sensor do?

The Oxygen Sensor detects the amount of oxygen in the exhaust gas and sends a signal to the engine control unit which adjusts the air fuel mixture to the optimal level.

Too much oxygen in the exhaust gas indicates a lean mixture, which can cause performance problems, including misfires. Too little oxygen indicates a rich mixture, which wastes fuel and results in excess exhaust emissions.

When does an Oxygen Sensor need to be replaced?

Exposure to carbon, soot, harmful gases, anti-freeze, chemicals plus thermal and physical shock will shorten the life of an Oxygen Sensor. This results in increased fuel consumption, poor engine performance and excessive exhaust emissions.

That's why checking for and replacing a worn out Oxygen Sensor is an important part of every routine service.

Oxygen Sensors with 1 or 2 wires typically have a service life of 50,000kms. While 3 and 4 wire sensors have a service life of approximately 100,000kms.

With this in mind, you need to check foe any vacuum leaks, exhaust leaks up stream of the sensor these are the main causes of a )2 sensor reading, often the sensors are extremely hard to remove as they bind the threads up with carbon, I would start of by having the checks done first and if ok, conceder having the sensor tested or replaced, start here.