Ignition Coil Secondary Circuit Malfunction (Cylinder 4)
The P2314 code indicates a problem in the secondary circuit of the ignition coil for cylinder 4. This circuit includes the coil itself, the spark plug, and the wiring between them. A fault can cause weak or no spark, leading to misfires, reduced engine performance, and increased emissions. Common causes include a faulty ignition coil, worn spark plug, or damaged wiring/connector.
1. Most Common Causes
- Faulty ignition coil 'E' (open or shorted internal secondary winding)
- Worn, fouled, cracked, or incorrectly gapped spark plug in the corresponding cylinder
- Damaged spark plug wire or coil boot causing arcing or high resistance
- Loose, corroded, or disconnected electrical connection at the coil connector
- Short to ground or voltage in the coil driver control circuit (primary side affecting secondary)
- Internal ignition driver failure within the PCM
2. Symptoms You Will Notice
- Check Engine Light on
- Engine misfire (especially under load)
- Rough idle
- Decreased fuel economy
- Hesitation or lack of power
3. Step-by-Step Diagnosis
Step 1: Scan for codes and note freeze frame data.
Step 2: Visually inspect ignition coil, spark plug, and wiring for damage.
Step 3: Swap ignition coil with another cylinder and see if code follows.
Step 4: Test spark plug condition and gap; replace if worn.
Step 5: Check resistance of ignition coil primary and secondary circuits with a multimeter.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with a misfire can damage the catalytic converter and reduce fuel economy. Have it diagnosed and repaired promptly.
How much does it cost to fix?▼
Typically $50-$150 for parts (ignition coil or spark plug) plus labor if done by a shop. DIY cost is lower.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.