Ignition Coil I Primary/Secondary Circuit Malfunction
Code P0359 indicates a malfunction in the primary or secondary circuit of ignition coil I (cylinder 9). This coil is responsible for generating the high voltage needed to ignite the air-fuel mixture in cylinder 9. The Powertrain Control Module (PCM) monitors the coil's primary circuit for proper current flow and the secondary circuit for voltage output. A fault can be caused by an open or shorted coil winding, a faulty driver circuit in the PCM, or wiring issues. This code often leads to misfires, reduced engine performance, and increased emissions.
1. Most Common Causes
- Ignition coil I has an open or shorted primary or secondary winding
- Wiring or connector for coil I circuit is physically damaged, corroded, or disconnected
- Short to ground in the primary or secondary wiring of the coil circuit
- Short to battery voltage in the coil control or power supply circuit
- Abnormal resistance at the terminals or connections of the coil circuit
- Internal PCM failure in the corresponding ignition driver (rare)
2. Symptoms You Will Notice
- Engine misfire on cylinder 9
- Check Engine Light illuminated
- Rough idle or hesitation during acceleration
- Decreased fuel economy
3. Step-by-Step Diagnosis
Step 1: Scan for codes and verify P0359 is present. Check for additional misfire codes.
Step 2: Visually inspect ignition coil I and its wiring for damage, corrosion, or loose connections.
Step 3: Swap coil I with a known good coil from another cylinder. Clear codes and test drive. If the code moves to the new cylinder, replace the coil.
Step 4: If the code remains on cylinder 9, test the coil's power and ground circuits with a multimeter. Check for 12V at the coil connector with key on, and continuity to ground.
Step 5: If power and ground are good, test the PCM's coil driver circuit using a lab scope or test light. If no signal, suspect a PCM issue.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with P0359 as it can cause engine misfire, reduced performance, and potential damage to the catalytic converter due to unburned fuel.
How much does it cost to fix?▼
The cost to replace an ignition coil typically ranges from $50 to $150 for parts and labor, depending on vehicle make and model.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.