Alright, Every once in a GREAT while, my SES light will come on during a ride... Theres no connection between weather/driving style/conditions other then it's been cold out side . Anyways, ive hooked up to a code reader (two of them) No codes came up... Ive even shorted the two pin's to make the ses flash.. all it flashes is 12... any idea's on what the heck is going on here? thanks for the help guys. the engine is a 2.8l Carbed Stock cc-Verajet (cali car if that helps at all)

Firebreed

"Fustrated to the max"

 

Could just be going temporarily lean or rich, tho AFAIK, the code should stay in the system?

 

yea thats what is bugging me.. If the computer isnt storeing any codes.. what other things is that computer doing?

 

I thought they stayed in the system untill power was cut?

Highly strange? Do you have another ecm, or can you get another ecm and see if that fixes it?

 

Not at the moment, i might beable to get a J-yard computer.. but with j-yard pieces you have no clue what your getting... is there any checks to do with the comp to see if it is working correctly?

 

Just an update to for you all, The SES light is coming on more frequantly now, i havent had a chance to put the car up on a scanner or short out the pins yet, looking to put another scanner on it sometime this comming week, any other ideas on what i can do to check it out? Ive also noticed lately that the car is running rougher, Going to to do a tune up (cap, rotor, wires) and maybe replace the coil (im sure its the stock coil) soon, any other idea's on what i should check? btw the scanners all say that the O2 is reading lean.... However i have yet to find any vacume leaks on the car.....

 

my SES would come on frequently when driving......turned out to be the EGR vacuum solenoid

 

Have you checked for the code soon after the light came on?

I have a couple of thoughts here:

1: The computer dumps the information after 40 warm up cycles. If it's been 20 days since the light was on, the code's long gone. (Drive it to work every day for 20 days, warms up twice a day...just for the people that would think that I'm crazy)

2: The computer might not have a full time hot like it should, causing it to lose memory after you turn the key off. Check the hot lead to the ECM from the battery.

 

if its not raining tomarow, ill check the codes as soon as it comes on, and ill also check the wireing to the ECM, and let you all know. thanks everybody for the help

 

i don't know whether this is bs or not, but a long time ago, i heard that the ses light has to be on for 2 minutes to set a code in the computer. i don't even know where i got that, but it may be worth considering...

 

That's not true, if the light comes on, it sets a code.

 

as soon as the ECM sees a problem thats code worthy, it sets the light, there is no time delay or anything for it. otherwise there would be tons of things that would never trip the light, like intermittent misfires, or EGR problems and all that.

 

have you tried jumping the pins and driving it? I do recall reading something about the light flashing (or not) for certain info. What exactly I cant remember tho I am sure someone else can enlighten the crowd about the open/closed loop thing.

 

When you ground the ALDL with the engine running it shows Open/Closed Loop status. If the light is flashing very quickly, it's in open loop. If the light is blinking an on/off cycle about once per second, it's closed loop.

When it's in closed loop(slower flashing) you can see whether it's rich or lean depending on if the light is on longer than it's off and vice versa. If it's on longer, it's rich, if it's off longer, it's lean.

Manual trans missions can really see this when you decel with the clutch engaged. The light will stay off as long as you are engine braking because the computer has literally shut off the injectors for the moment so it doesn't waste fuel when you don't need it.