P0678 on 2011-2016 Chevrolet Express (Express 2500, Express 3500, Express 4500 Cutaway) — Cylinder 8 Glow Plug Circuit
1 vehicles · 1 makes · $300-$1,800 repair
Most Reported On
P0678 is an OBD-II diagnostic trouble code meaning “Cylinder 8 Glow Plug Circuit.” A fault in the glow plug/heater circuit for cylinder 8. The control module detected an open or short in that individual glow plug circuit. This code is most commonly reported on 2011-2016 Chevrolet Express (Express 2500, Express 3500, Express 4500 Cutaway), with repair costs ranging from $300 to $1,800.
Common Causes
Typical Repair Cost
Based on 1 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
This is a powertrain code, so a basic OBD-II reader can read it. These read P0678.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple code reader for engine (P) codes on many compatible OBD-II vehicles. It does not support every vehicle or hybrid/EV application, and it does NOT read body, chassis or network codes; confirm exact-vehicle compatibility before buying.
- Read & clear engine (P) codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth scanner with a companion app that reads beyond the engine module — ABS, SRS and transmission — plus manufacturer-specific codes on many vehicles.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X V3.0 Elite OBD-II Scanner
by LAUNCH
Handheld scanner covering the four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level tablet with all-system coverage and bi-directional control, so you can command a module rather than only read it.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
What you can do yourself, and what needs a shop
Reading the code, clearing it, and watching whether it returns is a driveway job with the right scanner. These steps are not:
- Module programming or software updates — needs the manufacturer software or a J2534 pass-through with a paid subscription.
- Replacing a control module — most are VIN-programmed and immobilizer-registered, so a new one does nothing until it is coded to your car.
- Airbag/SRS component work — a stored fault can deploy a live device.
If the vehicle is still under warranty, check for an open recall or technical service bulletin before buying anything — the repair may already be covered.
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FAQ
What does P0678 mean?
P0678 stands for "Cylinder 8 Glow Plug Circuit." A fault in the glow plug/heater circuit for cylinder 8. The control module detected an open or short in that individual glow plug circuit.
What are the most common causes of P0678?
The most common causes of P0678 are: Faulty cylinder 8 glow plug, Open or short in the glow plug circuit, Corroded/damaged connector, Wiring damage, Glow plug module fault. The specific cause varies by vehicle.
How much does it cost to fix P0678?
Repair costs for P0678 range from $300 to $1,800, depending on the vehicle and root cause.
Which vehicles are affected by P0678?
Au7o has documented P0678 across 1 vehicle models from 1 manufacturers: Chevrolet.
Sources (3)
- article2011-2016 Chevrolet Express 2500/3500/4500 6.6L Duramax LGH Glow Plug Control Module Repair - documented failure modes: no power to glow plugs, open driver errors
- Forum$4,000 Duramax glow plug problem "not uncommon" per Chevrolet Customer Service - Chevy and GMC Duramax Diesel Forum
- ForumGlow plugs going bad - Chevy and GMC Duramax Diesel Forum
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.