Cylinder #6 Ignition Coil Short Circuit
Code P1266 indicates a short circuit between the high and low sides of the ignition coil for cylinder #6. This typically means the coil's primary or secondary windings have failed, causing a direct electrical path that disrupts spark generation. The engine control module (ECM) detects abnormal current flow and sets this code. Common causes include a faulty ignition coil, damaged wiring, or a shorted driver circuit in the ECM.
01. Most Common Causes
- Faulty ignition coil on cylinder #6
- Short circuit in wiring harness to coil
- Damaged ECM driver circuit
02. Symptoms You Will Notice
- Engine misfire on cylinder #6
- Check Engine Light illuminated
- Rough idle or hesitation during acceleration
03. Step-by-Step Diagnosis
Step 1: Scan for codes and confirm P1266 is present.
Step 2: Visually inspect ignition coil #6 and its connector for damage or corrosion.
Step 3: Swap coil #6 with another cylinder and see if the code moves.
Step 4: If code moves, replace the faulty coil. If not, test wiring and ECM.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
No, driving with a misfire can damage the catalytic converter and reduce fuel economy. It's best to repair promptly.
How much does it cost to fix?▼
Typically $50-$150 for a new ignition coil and labor if you DIY. Shop labor may add $50-$100.