Cylinder 8 Glow Plug Circuit Range/Performance
The P06C0 code indicates that the Engine Control Module (ECM) has detected a performance or range issue in the glow plug circuit for cylinder 8. This typically means the glow plug resistance is out of specification, the circuit is open or shorted, or the glow plug control module is malfunctioning. In diesel engines, glow plugs preheat the combustion chamber for cold starts; a fault can cause hard starting, misfire, or increased emissions.
01. Most Common Causes
- Faulty glow plug in cylinder 8
- Open or shorted glow plug wiring or connector
- Failed glow plug control module or relay
- ECM software or hardware issue
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Hard starting, especially in cold weather
- Rough idle or misfire on cylinder 8
- Reduced fuel economy and increased emissions
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm P06C0 and check for related codes.
Step 2: Visually inspect glow plug wiring and connector for cylinder 8 for damage or corrosion.
Step 3: Measure glow plug resistance with a multimeter; compare to spec (typically 0.5-2 ohms).
Step 4: Test glow plug control module output and relay operation.
Step 5: If all pass, update ECM software or replace ECM.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
You can drive short distances, but avoid cold starts and heavy loads. The vehicle may be hard to start and could misfire, potentially causing catalytic converter damage.
How much does it cost to fix?▼
Replacing a single glow plug costs $50-$150 including parts and labor. If the control module needs replacement, expect $200-$400.