Q: I have questions about my 2009 kia spectra's CEL and the codes I had read. Car run's good and was running good when light came on.

Given the three codes, a known issue with sensor wiring in that vehicle (to be discussed momentarily), and only 89,000 miles on the engine, I would judge the likelihood of sensor failure to be "average". That is, there are lots of other equally likely causes of the Codes and one, in particular, that to be ruled out as a threshold matter. If a diagnostic is "claimed" to show sensor failure be sure to ask if the sensor output was viewed on an automotive scope (or appropriate manufacturer scan tool) and if it was condemned on the basis of THAT sensor output data. If sensor output was not so viewed, the mechanic is merely guessing as to the cause of the Codes setting. Furthermore, if a sensor is replaced, be sure to RETAIN the old sensor (take it home) just in case in the coming days the check engine light illuminates again. If they do recommend changing the sensor, prior to changing the sensor carefully ask the Mechanic if the sensor is the ONLY faulty component that has caused the setting of those three codes, the implication being that if that sensor is replaced you will not have a recurrence of ANY of those three specific codes. If they can deal with all that in an intelligent manner, credibly, and to your satisfaction, you are good to go. Remember, it’s your car and your money. If they do not treat you in accordance with that reality, run for the exits. And, as you know, we are always here, so you do have other options to get your car repaired.

In Spectra’s there are reports of the Check Engine Light illuminating, signifying a fault with the oxygen sensor when in fact the real issue is simply a faulty electrical connection at the sensor. Kia vends a repair kit to address this possibility and you can ask the dealer about it. There is probably a Technical Service Bulletin published by Kia as well on this issue and the dealer will have access to that. If the sensor tests good on a scope, meaning it is not the cause of the fault, here is a short list of the other possible causes of the three codes you have written in about: MAF (Mass Air Flow) sensor is dirty or faulty; MAF sensor damaged due to leak in the silicone potting material used to protect the circuitry; vacuum leaks downstream of the MAF sensor; damaged vacuum or PCV line/connection; faulty or stuck open PCV; defective fuel injector(s); low fuel pressure; plugged fuel filter; exhaust leak between engine and first oxygen sensor; faulty fuel pressure regulator; faulty manifold absolute pressure sensor; and so forth. Basically, ANY condition that causes the engine to run lean or rick could be implicated in the three codes. Start with the simple things first, which of course is the electrical connection to the sensor. If you elect to have a certified mechanic from YourMechanic handle something like this, the service to request would be a check engine light diagnostic. Feel free to let us know how it goes and if you run into any difficulty or need further technical assistance.