Pulled out of the barn today into 15 degree weather. Within about 30 seconds check engine light came on. Code is P1172, a bad Primary O2 sensor A search of the forums shows that this is not uncommon for my 06 S.
My question is: Is this possibly related to the extreme cold weather? Don't want to buy a $230 part if I don't need to.

Any harm in driving like this for a few days, or should I park until it's fixed?

Thanks

 

There are three things which may set this code, the first two are free to fix. The third requires replacing the sensor. This sensor is basically a heated filament in the exhaust stream capable of measuring oxygen escaping from the engine. The sensor provides feedback to the ECM which then adjusts the air/fuel ratio to correct stoichiometry. If this sensor goes south then the car can run either very lean or very rich....both of which are a plug fouling (and other failure mode concern). In OBD-2 speak : Faulty Air/Fuel Bank1 Sensor. It is a critical sensor (the secondary O2 is not which I will explain shortly). So the free fixes. If the wire is either shorted (1) or connector loose (2) the signal to the ECM will be compromised, the ECU sees it and throws a code. So take a good look at the wire leading to the sensor first. Look for fraying, cuts, or other damage (OBD-II speak "Air/Fuel Ratio Bank 1 Sensor 1 Open/Shorted"). Disconnect and reconnect the connector a few times (this will assure the connector is seated and the operation will scrape the contacts reducing oxides and hopefully restoring electrical contact (OBD-II speak "Air/Fuel Ratio Bank 1 Sensor 1 circuit poor electrical connection"). If wiring is good and cycling connector does not fix contact the sensor is bad and must be replaced (Back to "Faulty Air/Fuel Bank 1 Sensor"). Primary is very important; secondary not so much.
Utah

P.S. Secondary 02 Sensor- Earlier cars (~1996) had OBD-I and only a primary O2 sensor in front of the catalytic converter. Later (post 1996) cars have OBD-II for their On-Board Diagnostics. By placing a second sensor behind the catalytic converter the health of the converter can be constantly monitored and theoretically air quality improved by catching defective (saturated) cats during emissions inspections.

 

Thanks for the detailed and educational reply. I cleaned the connections and checked the wires with no success. So I just ordered a new sensor.

Thanks again for your help.

 

There was actually a technical article about this.

http://ww2.justanswer.com/uploads/di...42_a07-006.pdf

 

Great link. The AP2 has model specific quirks (and vice versa for the AP1 by the way). I will PM the OP to assure he is aware his car needs a software update as well.

Utah

P.S the link is to a factory Technical Service Bulletin which applies to the car in question....

 

Replacing front O2, air/fuel sensor worked on my 2007, AP2.

Honda part number: 36531-PZX-013. Number 7, in diagram.

http://www.hondapartsoverstock.com/i...S2A4E0400A.jpg

 

Thank you!

 

After replacing the front air/fuel ratio sensor --- drove around all Sunday, no CELs!

 

Not sure where you live but I'd check for rodent damage. Especially in the cold, they like looking for tight/warm places (i.e. your engine bay) and if they're hungry or young and teething, they're gonna look for stuff to chew. Best indicator, look for dropping on top of the valve cover/intake manifold. Living in L.A., it gets pretty cold here at night during winter, needless to say not only are the people not used to the cold here but so are the animals. We get rodent damage here all the time so it's not as uncommon as you'd think. I always pop the hood and check for rat droppings before I start it if I let my baby sit for more than a week.