The P0679: Cylinder 9 Glow Plug Circuit code indicates an issue with the glow plug circuit for cylinder 9. Glow plugs are essential for starting diesel engines, particularly in cold conditions. A faulty glow plug, wiring issue, or malfunction in the control circuit can lead to this error.
P0679 – Quick Overview
| Code | Information |
|---|---|
| Meaning | P0679: Cylinder 9 Glow Plug Circuit |
| Is it serious? | Yes, as it can cause hard starting, especially in cold conditions. |
| Possible causes | – Faulty cylinder 9 glow plug circuit – Wiring issue – Faulty glow plug |
| How to diagnose? | – Test cylinder 9 glow plug circuit – Inspect wiring and connectors – Replace glow plug if necessary |
P0679 Meaning
The P0679 code indicates a malfunction in the glow plug circuit for cylinder 9. This issue can prevent the glow plug from heating up, causing problems with starting the engine, particularly in cold weather. The issue may be related to the wiring, control circuit, or the glow plug itself.
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 faults, which can give more insights. | OBD-II Scanner |
| Test the Cylinder 9 Glow Plug Circuit | Use a multimeter to test the voltage and continuity of the glow plug circuit for cylinder 9. Ensure the voltage meets the manufacturer’s specifications. | Multimeter |
| Inspect Wiring and Connectors | Inspect the wiring and connectors for cylinder 9’s glow plug for signs of damage, corrosion, or loose connections that could cause the issue. | Flashlight, Multimeter |
| Test the Glow Plug for Cylinder 9 | Test the glow plug in cylinder 9 to ensure it is functioning correctly. Replace if the glow plug is faulty. | Diagnostic Tool, Multimeter |
| Replace the Glow Plug if Necessary | If the glow plug for cylinder 9 is not functioning correctly, 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 that the cylinder 9 glow plug circuit is functioning properly. | 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)