Ignition Coil H Primary/Secondary Circuit Malfunction (Cylinder 8)
The P0358 code means the vehicle's onboard diagnostic system has detected: Ignition Coil H Primary/Secondary Circuit Malfunction (Cylinder 8). This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- easy
- Estimated cost
- $50 - $350 (parts and labor)
Best-selling code reader on Amazon. Reads and clears check engine codes on any 1996+ vehicle. Under $30.
Essential for diagnosing sensor codes, checking voltage, and testing circuits. Under $15 and pays for itself on the first job.
Affiliate links — we earn a commission at no extra cost to you.
Common Symptoms
- Engine misfire on cylinder 8
- Rough idle on V8 engine
- Check Engine Light illuminated or flashing
- Reduced power and acceleration
- Poor fuel economy
Probable Causes (Ranked by Likelihood)
- Faulty ignition coil on cylinder 8 Very High
- Worn or fouled spark plug on cylinder 8 High
- Damaged coil connector or wiring High
- PCM coil driver circuit failure for cylinder 8 Moderate
- Spark plug well moisture or oil contamination Low
Frequently Asked Questions
Can I drive with code P0358?
You can drive short distances with a steady Check Engine Light. If flashing, stop driving to prevent catalytic converter damage from unburned fuel.
Is cylinder 8 always the last cylinder on a V8?
Yes. Cylinder 8 is the rearmost cylinder on bank 2 of a V8 engine. On some trucks, this cylinder can be difficult to access due to its proximity to the firewall.
Can extreme cold weather cause ignition coil failure?
Cold weather does not directly cause coil failure, but it puts more demand on the ignition system. A marginal coil that works in warm weather may fail in cold conditions when the engine requires stronger spark for starting.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Swap cylinder 8 ignition coil with another cylinder and clear codes to test
-
Inspect the spark plug on cylinder 8 for wear, fouling, or incorrect gap
-
Measure coil resistance -- primary 0.4-2.0 ohms, secondary 6,000-15,000 ohms
-
Check the spark plug well for moisture, oil, or debris
-
Test PCM coil driver signal at the cylinder 8 connector
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Commonly Affected Vehicles
- 2007-2017 Ford F-150 V8
- 2008-2018 Chevrolet Silverado V8
- 2005-2015 Dodge Ram 1500 V8
- 2010-2020 Toyota Tundra V8
- 2009-2019 Ford Mustang V8
Related Codes
Explore More
Was this helpful?
Send this to whoever is fixing the car — your mechanic, or the person asking what the light means.