So I started throwing this code about a month ago. I have used cipher to clear the code twice already, hoping it was a fluke, but it comes back after ~300 miles. I think the code is an Infiniti specific code for A/F sensor driver's bank (I think the one that is in the cat).

I have S/C with vpro ems/osiris reflash and the sensor is plugged into PE metallic HFC's. I have o2 foulers stacked to avoid the cel, which has worked the past few years, and I recently passed emissions before I threw the p1281 code.

I'm not sure if the code is related to the fouler possibly going bad, or the sensor, or harness? Anyone have any thoughts/suggestions before I go to the dealer to check the harness/sensor/etc.?

thx.

 

It's your A/F driver's bank sensor. I've been throwing 1281 and 1283 for the past 4-6 months now. Doesn't really hurt you. Doesn't hurt to get it fixed but the dealer charges out the *** $700+ to be exact. (I had it done the day I needed to have my car re-registered but about 3 weeks later and 1 track day it came back. Pretty sure my tune burned them up again). Just buy the part online, I'm pretty sure you can find them for $80-$150 online and change it yourself. Well worth not blowing a hole in the side of your wallet.

 

I replaced the sensor and now the code is back. Is this code for the sensor in the manifold or the cat?

 

Manifold.

 

hmmm. I wonder what I need to do to resolve this. The sensor for that one was replaced not too long ago. I dunno if it could be the harness or fuse or if that's part of a replacement sensor? If it is b/c the tune is too rich for the sensor to give a voltage signal to the ecm, I'm not sure why the other bank wouldn't throw a code...but would there be a way to fool the ecm into thinking everything is ok from that sensor via uprev flash or f-con vpro. I'm also wondering if this is the reason for my idle jumping...

 

So far, I am still throwing the code and it the cel is coming on sooner, after resetting. One thing I noticed is that after the cel came on, my idle really started to go nutz and will not settle--jumping from ~200 rpms to ~1200 rpms. Next week I plan to have the sensors and harness/fuses checked, as well as change out my spark plugs (1 step colder NGK iridium), which I think might have been fouled after running pig rich from when my vpro got messed up. Also a pressure test to check for vacuum leaks..Maybe P1281 and my idle issue is related?

any other troubleshooting tips? thx.

 

jonnylaw, with the vpro setting different afr targets than your stock ECU, I expect you will find it difficult to get rid of all the O2/cat codes. With the Haltech and an OBD scanner, I could identify when a pending code popped up and readjust targets rich or lean and have the pending code disappear only to have it's counterpart appear. It was a never ending battle to dial in the tune exactly at all load points... I just gave up and used the reflash to get rid of all the O2/cat codes. You do need to re-enable them to pass OBD inspection, but that is possible by paying careful attention to drive cycles (to get sensors ready but not allow enough time to throw a code prior to testing).

 

thx for the info rcdash--you bring up some good points/suggestions. I am just wondering if/how the p1281 code is related to my idle jumping and how it seems to get worse when the code is thrown..

 

idle jumping may be related to the ignition timing being out of sync with what stock ecu expects. I had that problem with the Haltech until I enabled "copy through" timing in the load sites around idle... or it could be a vacuum leak either in intake or exhaust (check manifold and exhaust bolts?)... If you have dual widebands and they read fine (14.7), then it's likely not an exhaust leak.

 

^^dual widebands are reading fine--but running a little rich. I wonder if there is a similar option to "copy through" timing in the load sites around idle with the vpro--I will have to pass that info on to my tuner. I will also request a pressure test and check for leaks on the intake side.

 

Alternatively you can read the timing values in Cipher and compare that to what is set for the FPro and just reset them appropriately. I think that would work.

 

Ok, so its my Cosworth plenum that's the problem. It is leaking from the driver's side end cap! This is the same place it was leaking when it was intially installed, and was told by the vendor to reassemble and reseal the cap. This worked for a few months, But, unfortunately the issue is back. I hope the vendor/Cosworth USA can remedy this for me, b/c it is leaking badly and is the cause for my code and idle surge.