Cylinder 2 Glow Plug Control Circuit High
The P066D code indicates that the powertrain control module (PCM) has detected a high voltage condition in the glow plug control circuit for cylinder 2. This typically means the circuit has excessive resistance or a short to voltage, preventing the glow plug from operating correctly. Common causes include a faulty glow plug, damaged wiring or connector, or a failed glow plug control module.
1. Most Common Causes
- Faulty glow plug in cylinder 2
- Open or shorted wiring in the glow plug circuit
- Corroded or damaged connector at the glow plug
- Failed glow plug control module
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Hard starting, especially in cold weather
- Rough idle or misfire on cylinder 2
- Excessive smoke from exhaust during startup
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm the code and check for related codes.
Step 2: Visually inspect the glow plug wiring and connector for cylinder 2 for damage or corrosion.
Step 3: Measure resistance of the glow plug; should be low (typically 0.5-2 ohms). High resistance indicates a bad glow plug.
Step 4: Check voltage at the glow plug connector with key on; should be battery voltage. If not, test the control module and wiring.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code, as it can cause hard starting, poor engine performance, and potential damage to the glow plug system. Have it diagnosed and repaired promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on whether it's just a glow plug replacement or involves wiring repairs.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.