Ignition Coil Secondary Circuit Malfunction
The P2308 code indicates a problem in the secondary circuit of ignition coil 'B' (or a specific coil depending on manufacturer). This circuit includes the coil itself, the spark plug wire, and the spark plug. A fault here can cause weak or no spark, leading to misfires, reduced engine performance, and increased emissions. Common causes include a faulty ignition coil, damaged spark plug wires, worn spark plugs, or electrical issues like short circuits or open circuits in the secondary wiring.
01. Most Common Causes
- Faulty ignition coil
- Damaged or worn spark plug wires
- Worn or fouled spark plugs
- Short circuit or open circuit in secondary wiring
02. Symptoms You Will Notice
- Engine misfire or rough idle
- Check Engine Light illuminated
- Reduced engine power and acceleration
- Poor fuel economy
03. Step-by-Step Diagnosis
Step 1: Scan for codes and note freeze frame data.
Step 2: Visually inspect ignition coil, wires, and spark plugs for damage.
Step 3: Swap ignition coil with another cylinder and see if code follows.
Step 4: Test coil primary and secondary resistance with a multimeter.
Step 5: Check spark plug condition and gap; replace if necessary.
04. Commonly Affected Makes
05. 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.