P0358
UniversalIgnition Coil H Primary/Secondary Circuit Malfunction
Medium SeverityThis code indicates a problem with the primary or secondary circuit of ignition coil H, which is responsible for providing the spark to ignite the fuel in one of your engine's cylinders. A malfunction here will cause the engine to misfire, leading to reduced engine power and potentially poor fuel economy.
⚠️ Before You Begin (Safety First)
Always ensure the vehicle is turned off and cool before working on engine components. Disconnect the battery's negative terminal before servicing any electrical components to prevent accidental shocks or damage. Ignition coils operate with high voltage, so exercise extreme caution.
Common Symptoms
- Check Engine Light illuminated
- Engine misfires or runs rough
- Reduced engine power
- Poor fuel economy
- Rough idle
- Engine hesitation or stumbling during acceleration
Common Causes
- Faulty ignition coil for cylinder H
- Damaged or corroded wiring to the ignition coil
- Loose or poor electrical connection at the ignition coil
- Faulty Powertrain Control Module (PCM) - less common
- Damaged spark plug (can sometimes damage the coil)
Frequently reported on: Ford F-150 (2004-2008), Chevrolet Silverado (2000-2007), Dodge Ram 1500 (2002-2008), Jeep Grand Cherokee (2005-2010)
Diagnostic Steps
- Safely park the vehicle on a level surface and turn off the engine. Disconnect the battery's negative terminal.
- Locate ignition coil H. Refer to your vehicle's service manual for exact cylinder numbering and coil location.
- Visually inspect the ignition coil and its wiring connector for any signs of damage, corrosion, or looseness.
- If possible, test the resistance of the primary and secondary windings of the coil using a multimeter, comparing readings to manufacturer specifications.
- As a diagnostic step, you may swap ignition coil H with a coil from a different cylinder (if accessible and the misfire moves, the coil is faulty).
- If the coil is determined to be faulty, disconnect the electrical connector and remove the retaining bolts. Replace the faulty ignition coil with a new one.
- Reconnect all electrical connectors and the battery's negative terminal. Clear the P0358 code using an OBD-II scanner and test drive the vehicle.
👨🔧 When to Call a Professional
If you are experiencing misfires on multiple ignition coils, or if replacing the coil for cylinder H does not resolve the issue, it is advisable to consult a professional mechanic. This could indicate a deeper problem with the Powertrain Control Module (PCM) or the vehicle's main wiring harness.
Commonly Asked Questions
What does 'Ignition Coil H' refer to?
The 'H' designates a specific ignition coil in your engine's firing order or cylinder numbering scheme, typically cylinder 8 on many V8 engines or the eighth coil in a multi-coil system.
Can I drive my car with a P0358 code?
While it might be possible to drive short distances, it's not recommended. A persistent misfire can lead to reduced power, poor fuel economy, and potential damage to your catalytic converter over time.
Do I need to replace all ignition coils if I have a P0358 code?
Typically, you only need to replace the faulty coil for cylinder H. However, if other coils are old or show signs of wear, some mechanics recommend replacing them in sets or all at once for preventative maintenance.
What tools will I need to replace an ignition coil?
You will generally need a basic socket set, a screwdriver, a torque wrench, an OBD-II scanner to clear the code, and potentially a multimeter for testing.
How can I be sure it's the ignition coil and not something else?
A common diagnostic step is to swap the suspected faulty coil with a known good coil from another cylinder. If the misfire moves to the new cylinder's code (e.g., P0357 if you swapped with cylinder 7's coil), then the coil itself is faulty.