Ignition Coil Primary/Secondary Circuit Malfunction
The P0350 code indicates a malfunction in the primary or secondary circuit of the ignition coil. This circuit includes the coil itself, wiring, connectors, and the engine control module (ECM) driver. The ECM monitors the coil's performance; if it detects an open, short, or excessive resistance, it sets this code. This can lead to misfires, reduced engine performance, and increased emissions.
01. Most Common Causes
- Faulty ignition coil
- Open or short in coil wiring or connector
- Failed ECM driver circuit
- Poor electrical connection at coil or ECM
02. Symptoms You Will Notice
- Engine misfire or rough idle
- Check Engine Light on
- Reduced power and acceleration
- Increased fuel consumption
03. Step-by-Step Diagnosis
Step 1: Scan for codes and note any misfire counts per cylinder.
Step 2: Visually inspect ignition coil wiring and connectors for damage or corrosion.
Step 3: Test ignition coil primary and secondary resistance with a multimeter and compare to specs.
Step 4: Swap coil with another cylinder to see if misfire moves; if so, replace coil.
Step 5: Check for power and ground at coil connector with key on; if missing, trace circuit to ECM.
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.
How much does it cost to fix?▼
Typically $50-$150 for a single coil replacement, plus diagnostic fees if done by a shop.