Service soon engine light

rkn2903 · December 21, 2004

My 99 GMC 5.3l vortex service engine soon light comes on for about a week, then goes out for a couple of day, then back on. I've changed all 4 oxegen sensors, and gas cap because the guy at Auto Zone said it was a code because of my gas cap, so I bought a gas cap from them and the light stills come on for a week, then out again after openen the gas cap, should I buy a factory gas cap for my truck, or what could be the problem, never had this happen before.

TexasAggie · December 21, 2004

Sounds like a typical A-Zone parts guy...replace parts till the problem goes away. What code was your truck producing when they scanned the truck?

GM-Tech · December 21, 2004

A gas cap left loose after a fill up is the most common thing we see for evap leak codes, but failed caps are not that common. Also, there are many other things that can set that code. I would say the most common thing on your truck would be the evap vent valve. The likelyhood of it being the vent valve increases exponentially if you live or drive in dusty areas.

rkn2903 · December 22, 2004

GM Tech, what is a evap vent valve, and is it something I can fix myself, are would I have to take it to the dealer?

A gas cap left loose after a fill up is the most common thing we see for evap leak codes, but failed caps are not that common. Also, there are many other things that can set that code. I would say the most common thing on your truck would be the evap vent valve. The likelyhood of it being the vent valve increases exponentially if you live or drive in dusty areas.

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GM-Tech · December 22, 2004

GM Tech, what is a evap vent valve, and is it something I can fix myself, are would I have to take it to the stealers?

Sorry, can't help you further. I work for the "stealers" which means I probably should not be here offering my expertise for nothing!

stonedigity · December 22, 2004

Sorry to hijack your thread, but a quick question for GM-Tech... I've got a couple codes coming from my '99 Siverado RCSB 5.3 4X4 (NBS) and was wondering if you would cipher them for me. I know that at least one is due to the all too common ABS motor issue, but the other I'm not sure of. The numbers are C0281, C0267,and C0265. Any help would be appreciated. Alos, if you have a link to where I can find these things for myself would be great. Thanks.

mcreyaufmiller · December 22, 2004

If the code goes away, I would look towards the vents in the evap system. Also, please remember, there are dealers out there that are bending over backwards to help their customers as in my case, then there are dealers out there trying to screw people. It is not fair to catagorize all dealerships as stealerships.

GM-Tech · December 22, 2004

The numbers are C0281, C0267,and C0265. Any help would be appreciated. Alos, if you have a link to where I can find these things for myself would be great.

Do you have the problem with the ABS motor running all the time?

The 265 and 267 is related to the pump motor circuit and the EBCM relay circuit. The 281 is a brake switch circuit fault which could be a couple things including within the ABS itself and not the switch at all.

Sorry, no link. The service information that we can access on the web is only available to the dealership. I think you can pay for access too, but it ain't cheap. It's meant more for shops than DIY'ers.

stonedigity · December 23, 2004

GM-Tech...Yes, the motor will run all the time if I put the fuse back in. It's been this way for a while, and I've sort of learned to deal with it. On the dash, the ABS light and the parking brake lights always remain lit. The parking brake has seemed to be screwed since almost new. I never used the parking brake, and when I did, it went to the floor. Still this way. I seem to remember reading that there was a problem with a bad batch of clips or something like that for the early model trucks. The ABS motor I can get fixed, but for the parking brake, I'm not sure what to replace. I know the shoes are toast, but I'd like to find the root of the problem. As for the codes, I had them checked after the service engine light came on. The guy told me it was a misfire code and wouldn't say any more without $$$ so I reset the codes, and it hasn't come back on yet (~100 miles). The truck seemed to be sluggish and hesitating in 2nd gear when the light was on, weird. If you could enlighten me as to what the parking brake problem is that would be great. Thanks for the reply

GM-Tech · December 23, 2004

GM-Tech...Yes, the motor will run all the time If you could enlighten me as to what the parking brake problem is that would be great.

With certain ABS failures, BOTH the ABS light and the red brake light are turned on. So the red light may not be an indication of anything with your parking brake at all and in fact, I doubt that it is. Fix the ABS and you'll fix all your lights and "C" codes.

Of course, this has nothing to do with the parking brake shoes or mechanism in the rear. That's another issue.

redvett · December 23, 2004

stonedigity if you have the ABS motor running all the time go to this site.

http://www.circuitsolutions.info/

stonedigity · December 23, 2004

Thanks guys

rkn2903 · February 20, 2005

Does anyone no the part number are where i can purchase the evap vent valve, and where is it located on the 99 GMC seirra 1500 5.3l vortex? Thanks

MAGNUM · February 20, 2005

Does anyone no the part number are where i can purchase the evap vent valve, and where is it located on the 99 GMC seirra 1500 5.3l vortex? Thanks

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rkn2903, hello, I'm a newbie here so I hope I do this right! I had the same problem on a 2000 suburban and because I drive 30 miles + gravel roads the vent filter would get enough dust in it to set off the code. yours may be located in a little different spot but mine was located behind the tank about right above the rear axle, a black unit about the size of a small fist, popped the plastic cap off and washed with water, put it back in and worked great.