Cylinder 11 Glow Plug Circuit Malfunction
The P0681 code indicates a problem in the glow plug circuit for cylinder 11, typically found in diesel engines. The powertrain control module (PCM) has detected an abnormal voltage or resistance in the circuit, which may be caused by a faulty glow plug, open or shorted wiring, or a failed glow plug control module. This can lead to hard starting, especially in cold weather, and increased emissions.
1. Most Common Causes
- Faulty glow plug in cylinder 11 (internal open circuit or short circuit)
- Short to ground, short to voltage, or open circuit in the control wiring for cylinder 11 glow plug
- Damaged, corroded, or loose electrical connector at the glow plug or control module
- Defective glow plug control module
- Faulty PCM (uncommon)
2. Symptoms You Will Notice
- Hard starting, especially in cold weather
- Check Engine Light illuminated
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm the code and check for additional codes.
Step 2: Visually inspect the glow plug wiring and connector for cylinder 11 for damage or corrosion.
Step 3: Test the glow plug resistance with a multimeter; typical resistance is 0.5-2 ohms.
Step 4: Check voltage at the glow plug connector with the ignition on; should be battery voltage.
Step 5: If wiring and plug are okay, test the glow plug control module or relay.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code, as it can cause hard starting and potential damage to the engine if the glow plug fails completely.
How much does it cost to fix?▼
The cost to fix a P0681 code typically ranges from $50 to $150, depending on whether a glow plug or wiring repair is needed.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.