Cylinder 3 Glow Plug Circuit Malfunction
The P0673 code indicates a fault in the glow plug circuit for cylinder 3. Glow plugs are used in diesel engines to preheat the combustion chamber for cold starts. When the powertrain control module (PCM) detects an open or short circuit in the glow plug or its wiring for cylinder 3, it sets this code. This can lead to hard starting, misfiring, and increased emissions, especially in cold weather.
1. Most Common Causes
- Faulty glow plug in cylinder 3
- Open or short in glow plug wiring or connector
- Failed glow plug relay or fuse
- PCM issue (rare)
2. Symptoms You Will Notice
- Hard starting, especially in cold weather
- Engine misfire or rough idle
- Check Engine Light illuminated
- Excessive smoke on startup
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect glow plug wiring and connector for cylinder 3 for damage or corrosion.
Step 3: Test glow plug resistance with a multimeter (should be low, typically 0.5-2 ohms).
Step 4: Check for power at the glow plug connector with the key on (should see battery voltage for a few seconds).
Step 5: If power is present and glow plug is good, test the glow plug relay and fuse.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
You can drive, but starting may be difficult, especially in cold weather. It's best to repair promptly to avoid further issues.
How much does it cost to fix?▼
Typically $50-$150 for a glow plug replacement, plus diagnostic time. Costs vary by vehicle and labor rates.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.