[firefighter951]

Well I got my wish finally... after fueling up I started my drive home and after about thirty miles the SES light came on. P1278 and the readout said air fuel ratio sensor heater bank 1 failurr . I have done a little reading into it but where is it located and is there a way to test it with a multi meter?

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[firefighter951]

Sorry for the spelling.... posting from a phone is more difficult that I though it would be. So after more research and reading the FSM I tested the sensor (multimeter) and it tested fine. Also did a little more digging and found that there are several service bulletins about this particular problem.

 

[i68k]

posted in your other thread. seing you have a tsb for it, you should still try a new sensor first. sometimes ohm readings are good, but amperage is not, or vice versa. you should also look at the upper o2, it might be caked up with white stuff or something. but this is my other post:

P1278 NISSAN - Air Fuel Ratio (A/F) Sensor 1 Circuit Slow Response

usually when you get slow response, its time for a new one. this code didnt show me which bank, do you have more than one bank of o2 sensors? 2 o2 sensors is 1 bank, 4 o2 sensors is 2 banks. either way, the code i looked up is for you primary o2, which would be the first o2 is the exhaust stream, most likely the one on the top of the manifold. there is a way to test it, you need to test the ohm readout, use the specs in the fsm for correct ohm tolerances.

if you get a NEW o2 sensor, make sure it is NGK/NTK, or denso sensor WITH A CONNECTOR!!! for easy install. be sure to use anti-seize on the threads, dont get anti-seize on the tip of the sensor. DO NOT GET A BOSCH O2 SENSOR, YOU WILL HAVE MORE PROBLEMS!!!

 

[firefighter951]

Well time to get the wallet out eh? I guess it could be worse..... I was afraid the head-gasket had went like most others have when the SES light came on. Assume the worst and hope for the best hahah. I cleared the code today and added seafoam (hoping I might have just got bad gas and this would do the trick?) Also, on the way home from the gym tonight I noticed i do have a bit of a lag on pedal response when in drive, but not in neutral or park. Normal or not? I had planned on testing the tps tonight but the weather has a different idea for me.

 

[i68k]

i would at least pull the upper o2 and see what it looks like, they are like spark plugs, the color or residue will tell you a story. some people never change them, i change them at same time i do spark plugs, every 80k-100k miles. im dont remember your exact year/model, but take a look at rockauto.com, there's usually denso or ntk for under $100, just make sure when you buy one, it comes with the connector attached so you dont solder anything. DO NOT GET BOSCH, or you will have more problems! you'll be looking for an upstream sensor, or pre cat sensor. as for the lag, there is no load on the motor while youre in park or neutral. when youre in drive, your clutches are engaging, this is normal. also, its not likely your tps with the code you finally got, if the new sensor doesnt work, follow the tsb.