Glow Plug Module Control Circuit
The P0670 code means the vehicle's onboard diagnostic system has detected: Glow Plug Module Control Circuit. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $50 - $500 (parts and labor)
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Common Symptoms
- Check Engine Light on
- Glow plug system not operating
- Reduced system performance
- Warning indicators on dashboard
Probable Causes (Ranked by Likelihood)
- Faulty glow plug module or control circuit Very High
- Wiring damage or corrosion in the circuit High
- Poor electrical connection at module or component Moderate
- ECM or control module internal failure Low
Step-by-Step Diagnostic Procedure
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Use a scan tool to read data related to Glow Plug Module Control
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Inspect all related wiring, connectors, and grounds for damage, corrosion, or loose connections
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Measure circuit voltage, resistance, and continuity to identify the fault type
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Check for technical service bulletins related to this code for your specific vehicle
Common Fixes by Vehicle
What techs usually find when diagnosing P0670 on specific vehicles — tap your vehicle for the fix and the exact part:
2003-2007 Ford 6.0L Power Stroke Super Duty easy DIY
P0670 on the 6.0L Power Stroke means the Glow Plug Control Module (GPCM) has failed, which is extremely common. The GPCM lives on the driver-side valve cover and fails from heat/vibration. Replace with the updated Motorcraft DY-861 GPCM. Also inspect the valve cover harness -- if a glow plug tip has broken off, it may have damaged the harness connector. No-start cold = almost always GPCM on these trucks.
Labor: 1 hour2008-2010 Ford 6.4L Power Stroke easy DIY
6.4L P0670 is the GPCM located on the driver-side valve cover. Motorcraft DY-1219 is the updated part. Before replacing, check battery health -- the GPCM draws over 100A during heat cycles and weak batteries cause repeat GPCM failures. Replace both batteries if they're over 3 years old before condemning the GPCM.
Labor: 1 hour2001-2010 Chevy Silverado/GMC Sierra HD 6.6L Duramax (LB7/LLY/LBZ/LMM) easy DIY
Duramax P0670 points to the Glow Plug Control Module. The GPCM is on top of the intake or passenger-side inner fender depending on year. AC Delco 19299312 is the OE replacement. The GPCM fails from corrosion -- wash out the engine bay with water and you may have confirmed the cause. Also inspect for rodent damage to the harness.
Labor: 1 hourFrequently Asked Questions
What does P0670 mean?
P0670 indicates a fault in the glow plug module control circuit. This is an electronic control system code that affects the ECM's ability to manage the associated component or system.
Is P0670 a serious code?
This is a moderate concern that should be diagnosed soon but may not prevent driving short distances.
Can a low battery cause ECM-related codes?
Yes. Low battery voltage can cause various ECM and module communication codes. Always verify the battery is fully charged and the charging system is working before diagnosing electronic control module codes.
Sources
This page is built from documented references. Verify against your own service info before repair work.
P0670 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
See All Codes & Fixes for Your Vehicle
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