If you’re dealing with a P0670 code on your LLY Duramax or your glow plugs just aren't working, there’s a good chance your Glow Plug Control Module (GPCM) is the issue. These modules are a common failure, but finding a viable replacement can be difficult and expensive. We’ll walk through symptoms, causes, and the best solution to get your truck up and running smoothly again.

What Does a Glow Plug Control Module Do?

The Glow Plug Controller ensures your glow plugs get the right amount of power for the right amount of time. Glow plugs are essential for starting your engine, especially when it’s cold. Without glow plugs working properly, you’ll notice problems like hard starts, rough idling, and a general lack of engine power while your engine is warming up.

In a nutshell, the GPCM sends power to your glow plugs based on various signals it receives. If the module fails, though, it can disconnect power to the glow plugs altogether, causing the issues mentioned above.

What Causes Duramax Glow Plug Modules to Fail?

The problem comes from how the GPCM is designed. Originally, these modules weren’t built to handle the high current spikes that can happen when there’s a faulty glow plug or another electrical issue. These spikes can catastrophically damage the GPCM. This is why you’ll see a code like P0670, indicating that there’s an issue with the glow plug circuit.

When the GPCM fails, it often completely disconnects power to all of your glow plugs. As you can imagine, this means that your engine won’t start properly, or it will idle roughly and lose both power and efficiency. It’s a frustrating issue, but thankfully there are some easy solutions.

Are Aftermarket Parts a Good Solution?

Unfortunately, brand new replacements for these controllers no longer exist. There are a variety of aftermarket Duramax GPCMs available on the market, and while that might sound like an easy fix, it’s not usually the best route. The circuitry in aftermarket glow plug modules is very different from the original design, which can lead to communication and reliability issues. These aftermarket modules have caused a lot of frustration for truck owners which led us to create a better solution.

The Best Way to Fix the Duramax GPCM: Rebuild It

Instead of replacing your Duramax GPCM with something that’s going to lead to more issues down the road, the most reliable fix is to have the Duramax glow plug module rebuilt. By doing this, you’re not only fixing the immediate problem but also preventing future failures. Rebuilding your current GPCM is the best way to ensure it will last, and it’s also an affordable option.

At Circuit Board Medics, we specialize in remanufacturing Duramax glow plug controllers to make them better than new. The process isn’t simple—it involves machine disassembly of the module and repairing the circuit board itself. And this is exactly why the rebuild is so effective—it addresses the root cause of the problem and protects the module for the future.

Why Choose Circuit Board Medics?

If you’re tired of dealing with unreliable aftermarket parts, rebuilding your existing GPCM is the way to go. Here’s why Circuit Board Medics is the best choice:

• Fast Turnaround: We have your module fixed and shipped back to you in just one business day. No lengthy waiting periods!
• One-Year Warranty: You’ll have peace of mind knowing your rebuilt module is covered for a full year.
• Expert Support: If you’ve got questions or concerns, we’re available to help. We want to make sure everything goes smoothly for you and your issues are fully resolved.

Skip the unreliable aftermarket replacements and go for a rebuild that will keep your truck running like new for the long run. If you’re ready to have your truck running right again, you can explore the variety of Glow Plug Module Repairs and Exchanges for 6.6L and 5.2L diesel engines to find your exact part. If you’re unsure about something or just need more info, don’t hesitate to reach out. We’re always happy to assist.