Cylinder 2 Glow Plug Circuit Malfunction
The P06C6 code indicates that the engine control module (ECM) has detected an incorrect or malfunctioning glow plug in cylinder 2. Glow plugs are used in diesel engines to heat the combustion chamber for cold starts. This code typically means the glow plug resistance is out of specification, the circuit is open or shorted, or the glow plug control module has a fault. It can cause hard starting, misfires, and increased emissions.
1. Most Common Causes
- Glow plug in cylinder 2 is damaged or has resistance out of specification
- Wiring or connector for cylinder 2 glow plug has a short to ground, short to voltage, or open circuit
- Glow plug relay is faulty (if the system uses a central relay design)
- Glow plug control module is defective (in systems with individual electronic control)
- Corroded or loose connections in the cylinder 2 glow plug circuit
- Internal ECM failure (rare)
2. Symptoms You Will Notice
- Hard starting, especially in cold weather
- Check Engine Light illuminated
- Rough idle or misfire on cylinder 2
- Excessive smoke on startup
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Measure resistance of cylinder 2 glow plug; compare to spec (typically 0.5-2 ohms).
Step 3: Inspect wiring and connector for damage, corrosion, or shorts.
Step 4: Test glow plug control module output to cylinder 2.
Step 5: Replace faulty glow plug or repair wiring as needed.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
You can drive short distances, but starting may be difficult in cold weather. Prolonged driving can cause misfires and damage the catalytic converter.
How much does it cost to fix?▼
Typically $50-$150 for a single glow plug replacement, including parts and labor. Costs may be higher if the control module or wiring needs repair.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.