spacemanspif

iTrader: (5)

Hi folks,

So my car made it home last weekend is running very well. I'd like to thank everyone on the site of all of their help that I have gotten from using the search function. I am in the home stretch and knocking out little jobs every night.

In trying to get all my gauges up and running I was also playing with the wiring for the check engine light...but no dice.

1: It's my understanding that the computer provides the ground for the CEL. I have tested this with a volt meter and it seems to be correct (if I touch a live wire and the CEL wire I get 12v reading; if I touch the CEL wire and a ground I get nothing.

2: I know my bulb works because if I touch the black wire to a ground it will light up.

3: Power for the bulb comes from the switched power that I am using to power all my gauges and gauge lights.

So when I connect the CEL wire from the comp to the bulb ground and start the car the bulb doesn't light.

Am I correct that the CEL should light when I start the car? I haven't tested the light doing anything but start the car, but since it seems that EVERY car lights the CEL when its started I think starting car is a good way to test it.

Any ideas what could be causing my CEL to not light at start up?

Thanks,

Mike

LS1MCSS

iTrader: (18)

Uh, what motor/pcm do you have?

spacemanspif

iTrader: (5)

Sorry, 2004 5.3 with the blue/green computer.

1ltcap

so? when you turn the key on, engine off, your cel doesn't come lit at all? it should come on for about 2 seconds when you do that, and when you start the car, as a "self test".

do you have access to a scanner? if so, look at datastream, and see if the cel is being commanded "on".

is this vehicle an led that's part of the circuit board, or is it still a changeable bulb? if it's changeable, change it just for the hell of it, and see what happens.

spacemanspif

iTrader: (5)

Yes when I turn the key on, the CEL does not light, same for when I start the car. I have a hand held scanner but I don't think that I can see that kind of info but I'll double check it tonight. It is just a regular incandescent bulb, I might change it like you recommend just to see if it changes anything.

While typing this I just had a thought...When I read the live data without the light hooked up it throws the code for CEL not working, if I hook up the light and then delete the code would that change anything? (like maybe since the code is in the system the computer isn't trying to light the light?)

Thanks,

Mike

1ltcap

that might. also, check the little tabs on the socket that the bulb is in, along with the printer circuit where it contacts when installed. i've seen both of those go bad, and drive people crazy.

spacemanspif

iTrader: (5)

The light bulb is a stand alone socket that is hardwired so I don't have to worry about the printed circuit thankfully. The thing that is getting to me is that if I touch the negative to a good ground the light will light up, but if I connect it to the computer controlled ground and turn the key to "on" the CEL won't light.

spacemanspif

iTrader: (5)

Just checked with my scanner, it reads as the first line of live data "MIL circuit: off?" its an Actron scanner if that matters. Yes, there really is a "?" at after off.

Is this something that I need to take up with Current Performance who modded my harness and programmed my comp or is there some way I can do this at home without a programmer? I disconnected my battery in case this is something that just needs to be reset...

I'd really like to have a working CEL in the car so that I know if anything goes wrong as I drive down the road...I have too much money tied up in the car to just let it implode due to me not knowing something is wrong.


Thanks for all the replies thus far.

1ltcap

ok...that leads me to another question? did this start after the mod? if so, then you should talk with them before digging in too deep.

i see you're in turnersville. my shop's in cherry hill. if you want, i'll hook up my modis, and see what that sees.
i've never used one of the scanners you mention, and i've never seen one that asked me if the cel was on. i use an otc scanner, and the snap on modis. both of them generally have a line for MIL(for malfunction indicator light), and then the value is either on or off.

like i said, if you want me to plug in and scan it real quick, i'd be glad to take a minute or 5 and see if i can help ya out. just bear in mind.....i'm not the king of neat, and my shop reflects that, lololol

spacemanspif

iTrader: (5)

I might take you up on that offer next week. This weekend I am going to try and trace some wires and see if there is anything with a break in it or something, maybe its just a bent pin on the computer plug...

I'll PM you later for contact info and all that.

ls1_chevelle

iTrader: (9)

does your switched source see 12v while cranking? doubt it.

spacemanspif

iTrader: (5)

It might not but it does have power when the key is turned to "on" and does not light the bulb when that happens like cars normally do...and are supposed to do.

ls1_chevelle

iTrader: (9)

damn lol

is it a bulb or led?

spacemanspif

iTrader: (5)

I think I found the problem (pic of green plug):





According to http://www.lt1swap.com/2004vortec_pcm.htm, green plug pin #46 should be CEL control. Could someone confirm that my suspicions are correct and the brown/white wire is in the wrong position?

Thanks,

Mike

1ltcap

O just got home......it's late. i'll dig into my information system tomorrow, and see if i can find you a wiring diagram for that.

Emdmechanic

iTrader: (2)

That is the correct diagram , yes its on the wrong pin... Move it to 46 and you should be good to go.

spacemanspif

iTrader: (5)

Thanks EMD :-)

How do I go about moving pins around? Are there special tools required? Have a link for a walk through?

I feel like other wires will fall out of place when I do something like this.

-Mike

Emdmechanic

iTrader: (2)

A pick is all i used . Remove the cover on the front of the connector .. The green plastic piece. Then gently lift the lil plastic finger holding the pin in place. Pull the pin out and move it over. Make sure it locks in place .. slight tug on the wire. Replace the green cover and reinstall. Ill try and get some pics up shortly as i have one laying on the workbench . First pic is to release the cover .. Has the latch on both sides. Then in the second one lift the finger up and give the pin a little wiggle to unseat it and pull it out. Push it back in on pin 46 and you're golden. The wires/pins wont just fall out so no need to worry.

spacemanspif

iTrader: (5)

DONE!

Thank you so very much EMD. Took me all of about a minute and the light works fine now.

Thanks again to 1lt for his quick responses and willingness to help as well.

-Mike

Emdmechanic

iTrader: (2)

Glad to help... This site/people here has given me so much info and help, Im just trying to return the favor. Have fun!


Mike H.