# Check Engine Light in 03 Duramax



## TurbDies2500 (Oct 15, 2007)

Hey Guys, Just wondering if anyone knew some common things that set the check engine light to go on. I just had an alignment and I read that tire size and stuff like that can set it off because it screws with the gas mileage computer etc. I also read that changing brands of diesel fuel can also set it off. I am wondering if anyone has some ideas of what it could be. The truck runs perfect. It has about 100K miles. 

HELP


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## sechracer (Nov 4, 2007)

TurbDies2500;494734 said:


> Hey Guys, Just wondering if anyone knew some common things that set the check engine light to go on. I just had an alignment and I read that tire size and stuff like that can set it off because it screws with the gas mileage computer etc. I also read that changing brands of diesel fuel can also set it off. I am wondering if anyone has some ideas of what it could be. The truck runs perfect. It has about 100K miles.
> 
> HELP


Though I am not overly familiar with diesels, I have never heard of things like tire size setting a SES light. Also, fuel brand should not matter any.... I would go to someplace like autozone and get it scanned for free and start there.

Just my $.02
Tom


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## TurbDies2500 (Oct 15, 2007)

Thanks. I guess I will start there.


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## JPMAKO (Dec 10, 2003)

Go to auto zone and have them plug it in and tell you what code comes up.
Then go over to www.dieselplace.com and serach for your code.
That should give you a good idea of whats going on.

Do you notice anything different about the truck? 
Is it blowing a lot of smoke? Check your Oil and see if it smells like Diesel, If so you have an ionjector problem.

I just had a check engine light on my 2007 Duramax. I brought it to the dealer and they cleared the code, then about 2 days later it came back on. I brought it back again and they said I had a faulty EGR Valve. I told them while they had it to replace the belt as it was squealing a little bit when it was wet or cold. They called me back two days later and told me that they changed the belt but the squealing was my Turbo charger
Turns out the second EGR valve was faulty and it was making a hissing noise and they were about to change the Turbo for nothing. Thank God it was not the Turbo as I did not want the truck down for too long.

Jason


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## SNAKE85 (Feb 22, 2007)

Try replacing the fuel filter. It is a VERY common affliction with the Duramax's. You've gotta be real religious about changing them regularly as they are not as forgiving about being ignored as some others are. I've got two friends who had the same problem, once when we were on a road trip. Found a parts store, changed the filter in the parking lot & went on our merry way. Only about $40. Cheers


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