I need to reset the pass lock code 1998 K3500

What is your question?

One morning my K3500 would not start. I have had the injector pump rebuilt, the black box on top replaced,the lift pump replaced,the glow plugs replaced and new batteries replaced. The security light is on or flashing. It will pop off when either is used sometimes but other than that it won't run. It is showing code P1631

What makes this problem better or worse?

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How long has your 1998 Chevrolet K3500 had this problem?

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