Ignition Coil Primary Control Circuit Low
The P2306 code indicates that the powertrain control module (PCM) has detected a low voltage condition in the primary control circuit of a specific ignition coil. This circuit is responsible for triggering the coil to fire the spark plug. A low voltage reading suggests a problem with the coil itself, the wiring, or the PCM driver. This can lead to misfires, reduced engine performance, and increased emissions.
01. Most Common Causes
- Faulty ignition coil
- Open or shorted wiring in the primary control circuit
- Poor electrical connection at the coil or PCM
- Failed PCM (rare)
02. Symptoms You Will Notice
- Engine misfire
- Check Engine Light on
- Rough idle
- Reduced power and acceleration
03. Step-by-Step Diagnosis
Step 1: Scan for codes and note which cylinder is affected.
Step 2: Visually inspect the ignition coil and wiring for damage or corrosion.
Step 3: Use a multimeter to test the primary circuit resistance of the coil (specs vary, typically 0.5-2 ohms).
Step 4: Swap the suspect coil with another cylinder and see if the code moves.
Step 5: If wiring and coil check out, test the PCM output with a lab scope or test light.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code as it can cause misfires, damage the catalytic converter, and reduce fuel economy. Have it diagnosed promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for a DIY replacement of the ignition coil, or $100 to $300 if done by a shop including labor.