The P066D: Cylinder 2 Glow Plug Control Circuit High code indicates that the control module has detected a higher-than-expected voltage in the glow plug control circuit for cylinder 2. This may be caused by a faulty glow plug, wiring issues, or a malfunction in the control circuit. High voltage can damage the glow plug or prevent it from functioning properly, impacting engine starting performance, especially in cold conditions.
P066D – Quick Overview
| Code | Information |
|---|---|
| Meaning | P066D: Cylinder 2 Glow Plug Control Circuit High |
| Is it serious? | Yes, as it can lead to improper glow plug function, causing hard starting or damage to the glow plug. |
| Possible causes | – High voltage in the cylinder 2 glow plug control circuit – Faulty glow plug – Wiring issue |
| How to diagnose? | – Test cylinder 2 glow plug control circuit for voltage – Inspect wiring and connectors – Replace glow plug if necessary |
P066D Meaning
The P066D code indicates that the voltage in the control circuit for cylinder 2’s glow plug is higher than expected. This condition can result in the glow plug overheating or malfunctioning, leading to difficulties in starting the engine, especially in cold weather.
Step-by-step diagnostic guide
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check for additional codes related to the glow plug system or electrical issues, which could further assist in diagnosing the problem. | OBD-II Scanner |
| Test the Cylinder 2 Glow Plug Control Circuit for Voltage | Use a multimeter to measure the voltage in the glow plug control circuit for cylinder 2. Ensure the voltage is within the manufacturer’s specified range. | Multimeter |
| Inspect Wiring and Connectors | Inspect the wiring and connectors associated with the cylinder 2 glow plug for signs of damage, loose connections, or corrosion that could cause a high voltage condition. | Flashlight, Multimeter |
| Test the Glow Plug for Cylinder 2 | Test the glow plug in cylinder 2 to ensure it is functioning properly and not damaged by excessive voltage. Replace the glow plug if necessary. | Diagnostic Tool, Multimeter |
| Replace the Glow Plug if Necessary | If the glow plug for cylinder 2 is faulty due to high voltage, replace it to restore proper engine starting performance. | Replacement Glow Plug, Tools |
| Clear the Code and Test | After repairs, clear the code using an OBD-II scanner and test the vehicle to ensure the cylinder 2 glow plug control circuit is working correctly. | OBD-II Scanner, Vehicle Manual |
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Hi, I am Juraj “Yuri” Lukacko. I got frustrated by unhelpful and scammy mechanics, so I decided to learn everything about car diagnostics myself. I test dozens of new car diagnostic tools every month along with learning new strategies to fix and customize cars. About Juraj Lukacko (Yuri)