I'm trying to find out how many sensors there are on a 2007 Accord LX. My car started running different the last few days while driving to work. It would hesitate when taking off and if you let off the gas to slow down then go to take off again, there was a delay and "stutter" effect while getting back in the gas. Today my CEL came on so I pulled into auto parts store and they pulled codes. I can't remember the exact code but It was an O2 issue in Bank 1?? The guy at the store said he thought there were 4 sensors, 2 in front of catalytic converter and 2 behind.

I was very hesitant to buy a replacement until I knew how many there were and their location(s). Can anyone confirm how many and their locations. I plan on getting the codes when I go back tomorrow. I just want to know a little more about it so I get the right one and don't end up replacing one that is still good. The one he said I need was like 135.00 ( for the front) and rear ones were around $50. Also does anyone know which codes correspond to which sensors? From doing a little searching tonight I've found codes P0171 and P0174 but can't figure out what they correspond to.

 

Is this a 4 or 6 cylinder? 4 cylinder has two (one air/fuel ratio sensor and one secondary heated oxygen sensor), 6 cylinder has four (two air/fuel ratio sensors and two secondary heated oxygen sensors).

Get the actual code number and post it, instead of the description. Even for a specific sensor, there may be different codes that could give hints to a different problem.

 

Sorry, forgot to post that it is a 4 cylinder. I'm going back when they open in am to get specific code so I can pinpoint it. I'll repost ASAP.

 

Okay. Take your time, don't get the sensor just yet. I or someone will try to help you once you have the code(s). It is not always the sensor.

 

0171 is the code. "System too lean" bank 1 system 1.

 

Codes like P0131, P0132, P0133 indicate suspicious sensors. P0171 is a situation where the car's ECU "thinks" the sensor is OK but it's pointing to a true lean condition like maybe a vacuum leak or something.

Of course it's POSSIBLE for the sensor to be bad, but 2007 is pretty new-ish as far as the ECU being able to descriminate between a bad sensor and other operational issues.

Exhaust leaks? The O2 sensor actually measures the oxygen DIFFERENCE inside vs. outside. So exhaust blowing onto the outside of that sensor will throw off the measurement in the direction of "too lean". Probably the same for oily crud dripping on the outside of the sensor.

 

It may be a dirty Mass Air Flow (MAF) sensor. Is the air intake stock or aftermarket?

I recommend you check the air filter and air filter housing to ensure the filter rubber gasket is not pinched and the housing was properly attached; to prevent dirt and bugs getting through. Check the condition of the filter media while you're at it.

Then get something like CRC Mass Air Flow cleaner from an auto parts store and clean the MAF sensor. Although the attached article says use a vacuum, oily grime needs something like CRC MAF cleaner to remove it. Remove the sensor, then spray the cleaner inside the sensor and let it air dry, it dries quickly.

See attached article for info. on P0171 and the MAF sensor. I also included a pic. of the location of MAF sensor on the stock air intake.

 

If you look at the picture you posted,( just above of the MAF) where it's labeled by the white box. Well, if you look directly on the right side of the white box label, there is a hose connection. When I got under the hood and started looking this afternoon, I found that this hose/connection was disconnected. I reconnected it, disconnected the battery for 10 minutes to reset the code, and drive around about 30 minutes. It drove like normal and no CEL came on.
Yes, the MAF is clean, I checked it today. The air filter is good too, I checked it. Hopefully the hose that was disconnected was causing a vacuum leak issue and was the culprit all along.
Thanks everyone all all your assistance and great info. You prevented me from dropping around 150.00 for nothing by buying a new O2 sensor that wasn't needed.

 

Excellent; I love the simple fixes.

 

I am looking to buy the 02 Sensor 234-5010 Upstream and a new OEM Gas Cap,Will the new O2 Sensor be ok for the codes I am reading? Thank you.