Ignition Coil Primary/Secondary Circuit Malfunction
The P0350 code indicates a general malfunction in the primary or secondary circuit of the ignition coil. This circuit includes the coil itself, wiring, connectors, and the power/ground supply from the engine control module (ECM). A fault can cause weak or no spark, leading to misfires, reduced engine performance, and increased emissions. The ECM monitors the coil's primary circuit for current flow and the secondary circuit for voltage output; any deviation triggers this code.
1. Most Common Causes
- Faulty ignition coil
- Open or shorted wiring in the coil circuit
- Poor electrical connection at the coil or ECM
- Failed ECM (rare)
2. Symptoms You Will Notice
- Engine misfire or rough idle
- Check Engine Light illuminated
- Reduced power and poor acceleration
- Increased fuel consumption
3. Step-by-Step Diagnosis
Step 1: Scan for codes and note any additional misfire codes (e.g., P0300-P0308).
Step 2: Visually inspect ignition coil wiring and connectors for damage, corrosion, or loose connections.
Step 3: Test ignition coil primary and secondary resistance with a multimeter; compare to manufacturer specs.
Step 4: Check for power and ground at the coil connector with the ignition on; repair if missing.
Step 5: If all tests pass, suspect ECM fault; perform ECM power/ground checks and consider professional diagnosis.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with a faulty ignition coil can cause misfires, damage the catalytic converter, and lead to poor fuel economy and drivability issues.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for a single coil replacement, including parts and labor. Diagnosis may add $50-$100 if needed.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.