Glow Plug #6 Circuit Failure
The P0676 code indicates a malfunction in the glow plug circuit for cylinder #6. Glow plugs are used in diesel engines to preheat the combustion chamber for cold starts. A failure in this circuit can be due to a faulty glow plug, open or shorted wiring, a bad relay, or a PCM issue. This code is specific to diesel vehicles and can cause hard starting, rough idle, and increased emissions.
1. Most Common Causes
- Faulty glow plug #6
- Open or shorted wiring in glow plug circuit
- Bad glow plug relay or fuse
- Corroded connector at glow plug
- PCM failure (rare)
2. Symptoms You Will Notice
- Hard starting, especially in cold weather
- Rough idle or misfire on cylinder #6
- Check Engine Light illuminated
- Excessive smoke on startup
- Reduced fuel economy
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect glow plug #6 connector and wiring for damage or corrosion.
Step 3: Test glow plug #6 resistance with a multimeter (should be low ohms, typically 0.5-2.0 ohms).
Step 4: Check voltage at glow plug connector with key on (should be battery voltage for a few seconds).
Step 5: If voltage is present and plug is good, test glow plug relay and fuse.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
You can drive short distances in mild weather, but cold starts will be difficult and may cause excessive smoke. Prolonged driving can lead to unburned fuel damaging the catalytic converter.
How much does it cost to fix?▼
Replacing a single glow plug costs $50-$150 including parts and labor. If wiring or relay needs repair, costs may be higher.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.