Ignition Coil H Primary/Secondary Circuit Malfunction
Code P0358 indicates a malfunction in the primary or secondary circuit of ignition coil H (typically coil #8 on V8 engines). The Powertrain Control Module (PCM) detects an abnormal voltage or current in the coil's control circuit, often due to an open, short, or excessive resistance. This can cause misfires, reduced engine performance, and increased emissions.
1. Most Common Causes
- Faulty ignition coil H
- Open or shorted wiring in coil circuit
- Damaged connector or poor electrical connection
- Failed PCM (rare)
2. Symptoms You Will Notice
- Engine misfire or rough idle
- Check Engine Light illuminated
- Reduced power and acceleration
- Possible stalling or hard starting
3. Step-by-Step Diagnosis
Step 1: Scan for codes and note freeze frame data.
Step 2: Visually inspect ignition coil H and its wiring for damage or corrosion.
Step 3: Swap coil H with another cylinder and see if the code moves.
Step 4: Test coil primary and secondary resistance with a multimeter per specs.
Step 5: Check for power and ground at the coil connector with key on.
4. 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 due to unburned fuel. Short trips to a repair shop are okay.
How much does it cost to fix?▼
Typically $50-$150 for a DIY coil replacement, or $150-$300 at a shop including labor.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.