The P066F: Cylinder 3 Glow Plug Control Circuit High code refers to a higher-than-expected voltage detected in the glow plug control circuit for cylinder 3. This issue can result from wiring problems, a faulty glow plug, or a malfunction in the glow plug control circuit. High voltage can cause the glow plug to malfunction, leading to poor engine starts, especially in cold weather.
P066F – Quick Overview
| Code | Information |
|---|---|
| Meaning | P066F: Cylinder 3 Glow Plug Control Circuit High |
| Is it serious? | Yes, as it can lead to malfunctioning glow plugs and hard starting in cold conditions. |
| Possible causes | – High voltage in the cylinder 3 glow plug control circuit – Faulty glow plug – Wiring issue |
| How to diagnose? | – Test cylinder 3 glow plug control circuit for voltage – Inspect wiring and connectors – Replace glow plug if necessary |
P066F Meaning
The P066F code means that the control module has detected a higher-than-expected voltage in the glow plug control circuit for cylinder 3. This condition can cause the glow plug to overheat or fail to operate correctly, making it difficult to start the engine, especially in colder conditions.
Step-by-step diagnostic guide
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check for any additional related codes, particularly those related to the glow plug system or electrical faults. | OBD-II Scanner |
| Test the Cylinder 3 Glow Plug Control Circuit for Voltage | Use a multimeter to measure the voltage in the glow plug control circuit for cylinder 3. Compare the voltage to the manufacturer’s specifications to ensure it is within range. | Multimeter |
| Inspect Wiring and Connectors | Inspect the wiring and connectors associated with the cylinder 3 glow plug for any signs of damage, loose connections, or corrosion that could lead to high voltage. | Flashlight, Multimeter |
| Test the Glow Plug for Cylinder 3 | Test the glow plug in cylinder 3 to ensure it is not damaged by excessive voltage and is functioning correctly. Replace the glow plug if faulty. | Diagnostic Tool, Multimeter |
| Replace the Glow Plug if Necessary | If the glow plug for cylinder 3 is found to be malfunctioning due to high voltage, replace it to restore proper starting performance. | Replacement Glow Plug, Tools |
| Clear the Code and Test | After completing repairs, clear the code using an OBD-II scanner and test the vehicle to ensure the cylinder 3 glow plug control circuit is functioning correctly. | OBD-II Scanner, Vehicle Manual |
OBD-II scanner Buyer’s Guide
- Scanner features explained
- Different types of scanners
- Scanners for coding/odometer/ECU/checks
- Best picks + discount codes
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)