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2005 Chevy Duramax P0678 Code - Truck Won't Start After Water in Fuel and Filter Replacement

Model: 2005 Chevy Duramax Fault Code: P0678 Posted: 2017-08-15 10:41

Recently experienced water contamination in the fuel system, which caused injector knock and a misfire in cylinder 3. I replaced the fuel filter, added heat treatment and diesel fuel supplement, and the truck ran fine initially. However, two days later, it began having difficulty starting and now displays only the P0678 diagnostic code. The ambient temperature is currently 80°F, yet the truck will not start at all. I'm seeking advice on this issue—specifically, what the P0678 code means and how to resolve it. I've confirmed that only this one code is showing in my scanner.

Related fault codes
P0678
Comments (3)
Anonymous 2017-08-15 10:44

Thanks for sharing your experience. This helps clarify the context of the issue.

Anonymous 2017-08-15 11:08

The P0678 code typically indicates a glow plug circuit fault—this is usually one faulty glow plug, not a complete no-start condition. A simple test: use a test light to check if the glow plug wire has power when starting. If there's no voltage, that points to an electrical issue. Additional considerations: - Are all diagnostic codes being read by your scanner? Ensure it can access all modules. - Avoid using 'chip' or 'programmer' solutions—they are not reliable and may cause further issues. - It’s possible the water contamination in the fuel system was more severe than initially described, which could affect long-term performance.

Anonymous 2017-08-15 11:16

I only see the P0678 code currently, but I recently noticed that my new fuel filter is leaking from the bottom. This may have introduced air into the system, potentially contributing to the starting issues. I'm considering replacing it immediately.