Cylinder 5 Glow Plug Control Circuit Low
The P067C code indicates that the powertrain control module (PCM) has detected a low voltage condition in the glow plug control circuit for cylinder 5. This typically means the glow plug or its wiring has excessive resistance or a short to ground, preventing proper heating during cold starts. In diesel engines, glow plugs are essential for ignition; a fault can cause hard starting, misfires, and increased emissions.
1. Most Common Causes
- Faulty glow plug in cylinder 5
- Open or shorted wiring in the glow plug circuit
- Corroded or loose connector at the glow plug
- Failed glow plug control module or relay
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Hard starting, especially in cold weather
- Engine misfire or rough idle
- Excessive smoke from exhaust on startup
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect the glow plug wiring and connector for cylinder 5 for damage or corrosion.
Step 3: Measure resistance of glow plug 5; should be low (0.5-2 ohms). High resistance indicates a bad plug.
Step 4: Check voltage at the glow plug connector with key on; should be battery voltage. If low, trace circuit back to control module.
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 further damage. It's best to repair promptly.
How much does it cost to fix?▼
Typically $50-$150 for a single glow plug replacement, including parts and labor. Wiring repairs may add cost.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.