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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), GMC Mechanic
Category: GM
Satisfied Customers: 29396
Experience:  GM Grand Master Technician 2007. 14 years experience.
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2003 gmc sierra 1500 sle: the check engine light..P0443

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I have a 2003 gmc sierra 1500 sle, the check engine light constantly comes on code P0443, no one can find any problems, I have read and heard that this particular model has had this issue, is ther a remedy? I live in a state that requires inspection and the truck will not pass in this condition thank you for any help
Welcome. What have you tried or replaced in an attempt to repair this?
Customer: replied 7 years ago.
I have replaced the vapor solinoide, I have traced each vacum line checking for leaks, I have removed the canistor and blew air through it, I have changed the gas cap, I checked voltage at the solinoid, 14 volts, I checked the resistance 19-20 ohms, I noticed that the valv has a lot of movement so I put a light uninterfing coat of silicone under the ruber mount and on the o-ring
ok, The one thing the diagnosis on the code and year missed is the PCM. I have seen one that you could command the valve and it would not respond, but the code would set and sent you thinking the valve or vacuum lines is the issue. My bet is that if you measure the DC duty cycle while commanding the valve with a scan tool, the values will not match.
Customer: replied 7 years ago.
is there any post or area to go to find out how to do this and what is the solution?
This you need a Tech 2 scan tool to verify and the repair is a replacement PCM.
GM Tech (Cam) and other GM Specialists are ready to help you
Customer: replied 7 years ago.
thank you