The P066B: Cylinder 1 Glow Plug Control Circuit High code indicates that the control module has detected higher-than-expected voltage in the glow plug control circuit for cylinder 1. This can be caused by a faulty glow plug, wiring issues, or a problem with the control circuit. The glow plug helps start diesel engines by heating the air-fuel mixture, and a high voltage condition can affect its operation.
P066B – Quick Overview
| Code | Information |
|---|---|
| Meaning | P066B: Cylinder 1 Glow Plug Control Circuit High |
| Is it serious? | Yes, it can lead to improper engine starting, especially in cold conditions. |
| Possible causes | – High voltage in the cylinder 1 glow plug control circuit – Faulty glow plug – Wiring issue |
| How to diagnose? | – Test cylinder 1 glow plug control circuit for voltage – Inspect wiring and connectors – Replace glow plug if necessary |
P066B Meaning
The P066B code means that the voltage in the control circuit for cylinder 1’s glow plug is higher than expected. This can affect the glow plug’s ability to function properly, leading to difficulty starting the engine, especially in cold weather, and possibly damaging the glow plug over time.
Step-by-step diagnostic guide
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check for any additional codes related to the glow plug system or electrical issues. These codes can provide further context for the problem. | OBD-II Scanner |
| Test the Cylinder 1 Glow Plug Control Circuit for Voltage | Use a multimeter to measure the voltage in the glow plug control circuit for cylinder 1. Ensure the voltage is within the manufacturer’s specified range. | Multimeter |
| Inspect Wiring and Connectors | Inspect the wiring and connectors leading to the cylinder 1 glow plug for any damage, corrosion, or loose connections that could cause a high voltage condition. | Flashlight, Multimeter |
| Test the Glow Plug | Test the glow plug in cylinder 1 to ensure it is not receiving excessive voltage and is functioning as expected. If faulty, replace the glow plug. | Diagnostic Tool, Multimeter |
| Replace the Glow Plug if Necessary | If the glow plug for cylinder 1 is malfunctioning due to high voltage, replace it to restore proper operation, especially during cold starts. | 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 1 glow plug control circuit is working correctly. | OBD-II Scanner, Vehicle Manual |
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I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko