I'd appreciate some advice if you have experience in this area.

I have an '04 Accord V6 with 76,000 miles. Has been running fine, although gradually over the last few years the gas mileage has gotten worse. Now down to around 20mpg around town and maybe 26 freeway.

The Check Engine Light lit up. ODB code p2243 Rear Air/Fuel Ratio (A/F) Sensor (Bank 1, Sensor 1) VCENT Line High Voltage It went out by itself. Now it is back.

I'm trying to decide whether to just change the sensor, or pay to have a pro troubleshoot it. Seems like it could be a bad sensor, or it could be any of a number of things, such as fouled plug in bank1 , or bad coil in bank1, or dirty injector in bank1, etc. etc.

Also please confirm that Bank1 is closest to the firewall, Sensor1 is the "upstream sensor" (accessed from on top in the engine compartment), and that a Denso 234-5010 would be the correct OEM replacement.

Bottom line - would you "plug and pray" or would you have a pro troubleshoot?

Thanks,
Bill

 

why would you pay someone to tell you what you already know just replace the sensor and yes denso is a OEM replacement or you can use NTK. those oxygen sensors are usually only good for 60,000 miles evan if a cell code doesn't come up there still dirty which leads to bad fuel economy. i recently replaced mine with a denso i got it cheap at advanced auto usually there 200-250 i got it for 90 on sale. the upstream sensor is before the cat coverter downstream is after the cat.

 

All O2 sensors have a limited lifespan,Here is how to replace :locate the sensor on the passenger side of the Honda, directly on top of the exhaust manifold. The sensor looks like a white rubber plug.
Use a socket wrench along with an oxygen sensor socket to loosen the sensor. Turn the wrench counterclockwise and continue to loosen the sensor until it can be removed. Pull the sensor out of place and discard it.
Insert a replacement O2 sensor into place on the manifold and push it into place. The sensor plugs into place; you will hear a click telling you it's secure.