Cylinder 5 Glow Plug Circuit
The glow plug for cylinder 5 isn't heating up properly, which makes diesel fuel harder to ignite in cold starts. Think of it like a lighter that won't spark—the engine struggles to fire up.
The ECU monitors voltage and current draw through the cylinder 5 glow plug circuit during the glow plug pre-heat phase. It detects open circuits, shorts to ground, or excessive resistance that indicates a failed plug or wiring fault. The circuit is typically commanded on for 1–10 seconds before engine start, depending on coolant temperature.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Glow plug circuit current | 8–15 amps during preheat | Below 2 amps or no current detected |
| Circuit voltage drop | 0.5–2 volts across relay/plug | Above 3 volts or open circuit |
Code P0675 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P0675 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.