Ignition Coil Secondary Circuit Malfunction (P2308)
The P2308 code indicates a problem in the secondary circuit of the ignition coil, which is responsible for generating the high voltage needed to create a spark at the spark plug. This can be caused by a faulty coil, damaged wiring, or a poor electrical connection. The secondary circuit includes the coil output, spark plug wire, and spark plug. A malfunction can lead to misfires, reduced engine performance, and increased emissions.
1. Most Common Causes
- Faulty ignition coil 'C' with internal damage, open secondary winding, or shorted secondary winding
- Deteriorated, cracked, or high-resistance spark plug wire
- Spark plug with incorrect resistance or worn electrodes
- Corroded, bent, or poorly contacting pins in the ignition coil 'C' connector
- Secondary circuit wiring damaged by heat, chafing, or shorted to ground
- Intermittent wiring harness fault due to engine movement
2. Symptoms You Will Notice
- Engine misfire or rough idle
- Check Engine Light illuminated
- Reduced engine power and acceleration
- Poor fuel economy
- Engine hesitation or stumbling
3. Step-by-Step Diagnosis
Step 1: Scan for codes and verify P2308 is present.
Step 2: Visually inspect ignition coil, wires, and spark plugs for damage or corrosion.
Step 3: Use a multimeter to test coil primary and secondary resistance per manufacturer specs.
Step 4: Swap coil with another cylinder to see if misfire moves; if so, replace coil.
Step 5: Check spark plug condition and gap; replace if necessary.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can cause catalytic converter damage from unburned fuel. Short trips to a repair shop are okay.
How much does it cost to fix?▼
Typically $50-$150 for a single coil replacement, plus labor if done by a shop. DIY can be cheaper.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.