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Ask Eric Gardner Your Own Question
Eric Gardner
Eric Gardner, ASE Certified Technician
Category: GMC
Satisfied Customers: 171
Experience:  ASE, Bachelors Degree in Automotive Technology, Automotive Technician for 5 years
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2005 GMC top kick 4500. I am getting a p0642 code and p0670.

Customer Question

2005 GMC top kick 4500. I am getting a p0642 code and p0670.
The truck will shut down indiscriminately. Sometimes it will restart other times it will not start for hours. Help
Submitted: 6 months ago.
Category: GMC
Expert:  Eric Gardner replied 6 months ago.
Hello. Based on your description of the codes and the vehicle not wanting to start, and the fact that it can be intermittent issue, my experience with these truck can fall into two different issues.1. The cheapest and easiest fix would be to replace the fuel filter. I have seen this same issue many times and the symptoms are the same. The fuel filter is so dirty that the injectors are not getting the fuel pressure needed to open the injector pintles.2. This will be a more expensive fix. The glow plug control module on these truck is notorious for going bad. The result is a no start condition, and/or the vehicle dying while being driven. I am confident that one of these two things will correct the issue at hand.
Customer: replied 5 months ago.
we have multiple trucks doing this issue. It is definately not he fuel filter. We have changed those multiple times also we do PM religiously and change fuel filter every other oil change. We will try the Glow plug module.
Let me ask you, will a Glow plug module cause the truck to start fine in the morning but if you shut it down it will not start again for an indiscriminate amount of time possibly not for days?? we have an exact truck doing this as well.