Cylinder 10 Glow Plug Control Circuit Low
The P069C code indicates that the powertrain control module (PCM) has detected a low voltage condition in the glow plug control circuit for cylinder 10. This typically means the glow plug or its wiring has excessive resistance or a short to ground, preventing proper heating for cold starts. The glow plug system is critical for diesel engines to ignite fuel in cold weather.
1. Most Common Causes
- Glow plug for cylinder 10 is open or has excessive internal resistance
- Damaged, corroded, or loose wiring in the glow plug control circuit
- Short to ground in the glow plug control circuit harness
- Corroded, oxidized, or bent pins in the glow plug connector
- Faulty glow plug relay (if individual relay or module design is used)
- Internal failure of the glow plug control module or ECM
2. Symptoms You Will Notice
- Hard starting, especially in cold weather
- Check Engine Light illuminated
- Rough idle or misfire on cylinder 10
- Excessive white smoke from exhaust 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 10 for damage or corrosion.
Step 3: Measure resistance of glow plug cylinder 10; should be low (0.5-2 ohms). High resistance indicates a bad glow plug.
Step 4: Check voltage at glow plug connector with key on; should be battery voltage. If low, test relay and wiring.
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 damage the catalytic converter or cause other issues.
How much does it cost to fix?▼
Typically $50-$150 for a single glow plug replacement, including parts and labor. If wiring or relay is faulty, costs may be higher.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.