Has anyone else had a "SES" light that constantly is on? I started the mods on my "L" a year ago, and from the start, the "SES" light came on. I will reset it, and a week later, on again! The only code I have is "lean / bank 1 and 2". I replace my fuel filter every other oil change, so I know it isn't that. The "L" runs great...no problems...so....the question is...what the heck is causing it? Any ideas? Maybe injectors? Please advise.

 

Try running without your breather(put the oil cap back on). I bet that will clear it up.

David

 

sounds like the first step in figuring out your SES Light
It is possible the tuner never programed you chip for the breather. Some trucks can run a breather without programing the chip for it, some can't

 

I know exactally what the problem is, Mine did it last week. It is your Oxygen Sensor, It is a b!tch to get at.there are 2 numbers on the work order see if one of these are a part number it will be DY*835* or 9F472

 

I have taken the breather cap off...and it still did it. I called my tuner and he said the he DID program the chip for it. I went back in and he reflashed the chip the "ensure" it was on there. But, within a week, it was back on. It is SO annoying! I haven't thought of the oxygen sensor....hmmmm Wouldn't it be giving me a code for the oxygen sensor then? Which oxygen would it be if it was the problem?

 

Have you checked your A/F ratio on a dyno? Or at least checked your O2 voltages @ WOT? Maybe you ARE running lean. I'd check it, you don't want to go BOOM.

 

I'd be somewhat surprised if it's your O2 sensor, unless you have a broken connection. You should reset the computer, and put your breather cap back on. If you still get the code, then my first guess would be that you have a vacuum leak. I had one on a different Ford product. The vehicle ran fine, idled good, no indication of the leak. I was not able to find out where it was leaking, so I resealed the upper intake, and that fixed it. My point is that the leak could be so subtle that you might not be able to detect it.

 

i was told the same thing by JDM.... but my chip was NOT programmed for it... ended up just not using the breather....


check for any loose hoses, mine always throws lean codes if a hose is loose

 

Word for word this is how the work order reads.

Cause: 27685WDS hook up test OB11 System pin point test codes lead, Bank 1 Monitor EGO Sensors, Check for any vacumn leaks, Ok. Checked fuel is Ok.
etc ,etc, etc.

I'am going to scan this work order and post it. I would like to help you pin point the problem if any of this lititure may help you.

 

AWESOME...that is some really good info. I am going to be under the hood today and will check for leaks. Still interested in how the O2 sensors will throw the lean code??? As for the dyno numbers...hmmm...I will have to look at my dyno sheet. When I dyno'd after my last chip burn, I didn't notice anything that stood out. The help I get on this site is second to none...thanks guys...you rock!