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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29427
Experience:  GM Grand Master Technician 2007. 14 years experience.
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Chevrolet Silverado 1500 Classic LT Check engine light is

Customer Question

Check engine light is on omst of the time on my 2003 Chevy Silverado 5.3 motor. It runs fine, passes Colorado emissions test. Should I be concerned?
Submitted: 5 years ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 5 years ago.

GM Tech (Cam) :

Hello, I'm Cam. Please include all the details about your issue so I can accurately advise you. I cannot see your vehicle so please be detailed.

GM Tech (Cam) :

Do you know what code set?

Customer:

No. I don't have a code reader

GM Tech (Cam) :

Ok it could be a gas cap, other emissions issue, knock sensors, just about anything, can you get a code reader or get a part store to read the cods?

Customer:

Yes, I can have a parts store read the codes. If not, I'll get a reader. I replaced the gas cap in March, but it did not help much. The light did not come on as often, so I continued to use the old cap. Doe this emissiion system have a 100,00o mile warranty?

GM Tech (Cam) :

No, they do not on these,

GM Tech (Cam) :

Get the code then return here to me with it and I can help you figure out if we need to deal with it and what the costs would be .

Customer:

Can I get back to you tomorrow on this?

GM Tech (Cam) :

sure.

GM Tech (Cam) :

Bookmark this page so you can easily navigate back to it, and so you know, you can reply at any time for follow up information regarding this issue, even after you accept my answer and I will reply. Please don't forget to click accept at some time as that is my only means of compensation for assisting you.

GM Tech (Cam) and 7 other Chevy Specialists are ready to help you
Customer: replied 5 years ago.

I got the codes read at O'Reily Auto Parts and the mgr said it was low voltage to all 4 oxygen sensors and also low voltage to the MAF sensor. I did not write down the codes, just the parts that were malfunctioning according to the codes.

 

I cleaned the MAF sensor with the proper cleaner, reconnected the battery, test drove the truck and the check engine light came on after a few minutes of driving.

 

I have not replaced any parts yet.

Expert:  GM Tech (Cam) replied 5 years ago.
Was the one for the Maf a p0101?
Customer: replied 5 years ago.
I'll find out tomorrow.
Expert:  GM Tech (Cam) replied 5 years ago.
Thanks.
Customer: replied 5 years ago.
The MAF code was p0101. I have been out of town for a while, thus, I did not respond as soon as I thought.
Customer: replied 5 years ago.
I would like a reply to the above response I sent three times now. Twice, Sun. 11/6 and once today, 11/7/11
Expert:  GM Tech (Cam) replied 5 years ago.
Sorry, there is a site error and I do not see any responses on the days you indicate, can you ask one more time so I can answer?
Customer: replied 5 years ago.
Yes, the MAF code was p0101. Now what?
Expert:  GM Tech (Cam) replied 5 years ago.
Yes, this could be a dirty MASS AIR FLOW SENSOR, plugged air filter or plugged exhaust. Can you check those and see?
Customer: replied 5 years ago.

I cleaned the MAF filter with MAF spray cleaner, as previously noted. The check engine icon stayed off until the engine reached operating temp, then it cameon again. Should I replace the MAF sensor?

 

I installed a K&N air filter, July, 2010 to improve air flow through the engine because I pull a 4000 lb travel trailer over 12,000' Colorado mountain passes in the summer. The filter seems to give the engine a little more torque under these conditions. The filter has about 12,000 miles on it? Should I clean it or simply replace it with an disposable paper filter?

 

The exhaust seems to be clear of obstructions by visual inspection of the tail pipe.

Expert:  GM Tech (Cam) replied 5 years ago.
The oil from the filter does coat the sensor and can cause issues as in change of readings.
I would test the back pressure, you need to use the pressure tester in place of the front oxygen sensors and get a pressure, that is the only way.
Customer: replied 5 years ago.
I'll have the back pressure tested. I'll also replace the air filter with a paper one.
Expert:  GM Tech (Cam) replied 5 years ago.
Ok, let me know what the result.