P0358: Ignition Coil H Primary/Secondary Circuit Malfunction
Quick Answer
Not safe to drive
P0358 means the engine computer detected an electrical fault in the primary or secondary circuit of ignition coil H, which fires cylinder 8. It only exists on engines with eight or more cylinders, so you will see it on V8s, V10s and V12s. Expect a misfire on cylinder 8; the coil itself is the usual cause, then the plug, the connector or the wiring.
- Severity
- Moderate · Ignition
- Estimated repair cost
- From €55 to €1500+, varies by vehicle
€55 or €1500, depending on your car.
- Replace ignition coil H (cylinder 8) only€55–€210
- Engine computer repair or replacement (failed coil driver, rare)€500–€1500
A scan shows whether P0358 is really stored on your car, which codes sit next to it and how urgent each one is. You can do this parked, with the ignition on.
A scan needs a Bluetooth OBD2 adapter (Bluetooth LE on iPhone), about €25-60; the built-in demo runs without one. See which adapter to buy
What does P0358 mean?
P0358 is a ignition-related diagnostic trouble code classified as moderate severity.
What are the symptoms of P0358?
- Check engine light on, usually with a cylinder 8 misfire code (P0308) stored as well
- Rough idle with a shake from the one cylinder that is not firing
- Hesitation and loss of power when accelerating
- Check engine light flashing under load while the misfire is active
- Fuel consumption up noticeably
- Raw fuel smell from the exhaust
- Harder starting when the engine is hot
What causes P0358?
Failed ignition coil on cylinder 8 (open or shorted winding)
: high
Worn or fouled spark plug on cylinder 8 overstressing the coil
: high
Cracked coil boot or plug lead arcing to the cylinder head
: medium
Corroded, loose or oil-soaked connector on the cylinder 8 coil
: medium
Oil in the spark plug well from a leaking valve cover gasket
: medium
Chafed or heat-damaged wire between the engine computer and the coil
: low
Failed coil driver inside the engine computer
: low
Is it safe to drive with P0358?
No - address this immediately. You can limp to a workshop, but a coil that is not firing sends unburned fuel from cylinder 8 into the exhaust, where it overheats the catalytic converter. Get it fixed within a day or two, and if the check engine light flashes, stop driving.
How do you diagnose P0358?
- Read all stored codes and the freeze frame. A cylinder 8 misfire code (P0308) stored alongside P0358 confirms the cylinder is really dropping out, not just logging an electrical glitch.
- Find cylinder 8 in the service data for your engine. Coil H follows the engine's own cylinder numbering, and on V engines that numbering differs from maker to maker.
- Remove the cylinder 8 coil and inspect the boot for cracks, carbon tracks or oil, and the connector for green corrosion, bent or pushed-back pins and a broken locking tab.
- Swap the cylinder 8 coil with the one from cylinder 6, clear the codes and drive. If the fault moves (P0358 becomes P0356), the coil is bad. If P0358 returns, look at the plug, connector and wiring.
- Pull the cylinder 8 spark plug and check the gap, electrode wear and any oil or fuel fouling. A worn plug makes the coil work harder and can kill a new coil quickly.
- Key on, engine off: confirm battery voltage at the coil supply pin against a good ground. While cranking, check that the engine computer is switching the trigger wire with an LED test light or an oscilloscope. Avoid an ordinary bulb test light, which can load the trigger circuit on coils with a built-in igniter.
- Follow the harness towards the engine computer looking for chafing, heat damage or rodent bites, especially where it runs over the back of the engine or close to the exhaust.
- If coil, plug, supply and wiring all pass, the coil driver in the engine computer is the remaining suspect. That needs a workshop with an oscilloscope and the wiring diagram.
How much does P0358 cost to fix?
| Repair | Parts Cost | Labor Cost | Total Estimate | DIY Difficulty |
|---|---|---|---|---|
| Replace ignition coil H (cylinder 8) only | €25–€120 | €30–€90 | €55–€210 | Easy |
| Replace coil H plus the spark plug on cylinder 8 | €35–€150 | €40–€120 | €75–€270 | Easy |
| Full coil set and spark plug set (on a V8, eight of each) | €250–€900 | €120–€350 | €370–€1250 | Moderate |
| Repair coil connector pigtail or harness section | €10–€60 | €60–€180 | €70–€240 | Moderate |
| Valve cover gasket on one bank of a V8 (oil in the plug wells) | €60–€200 | €440–€600 | €500–€800 | Moderate |
| Engine computer repair or replacement (failed coil driver, rare) | €400–€1200 | €100–€300 | €500–€1500 | Professional |
Prices estimated as of October 2026. Costs vary by region, vehicle, and shop.
Full repair guides
P0358 on specific vehicles
P0358 on Chevrolet
Chevrolet Silverado 1500 5.3 V8 (Gen IV)
P0358 on BMW
BMW 5 Series 545i / 550i (N62 V8) · BMW X5 xDrive50i (N63 twin-turbo V8)
P0358 on Audi
Audi S5 Coupe (B8, 4.2 FSI V8)
Related diagnostic codes
Common questions about P0358
- Which cylinder is coil H?
- Coil H is the coil for cylinder 8. On GM V8s cylinder 8 is the rearmost cylinder on the right bank, and on Ford V8s the rearmost on the left bank, in both cases right up against the bulkhead. Check the service data for European V8s, which follow each maker's own numbering.
- Can a bad spark plug cause P0358?
- Yes. A worn or fouled plug on cylinder 8 forces the coil to produce a higher voltage, which can break down the coil and set the circuit code. Replace the plug when you replace the coil, or the new coil can fail the same way.
- How do I confirm the coil is faulty?
- Swap the cylinder 8 coil with the one from cylinder 6, clear the codes and drive. If P0356 appears, the coil is bad. If P0358 comes straight back, check the connector, the wiring and finally the engine computer's coil driver.
- Is it safe to drive with P0358?
- Only far enough to reach a workshop. With cylinder 8 not firing, unburned fuel goes into the exhaust and overheats the catalytic converter. A flashing check engine light means stop driving.
- Do rear coils fail more often?
- They can work in harsher conditions. The rear cylinders of a V8 sit closest to the bulkhead, where heat builds up, and rear plug wells are the hardest to inspect for oil or water. A front coil can fail just as well, though, so always confirm the faulty coil with the swap test rather than by its position.
Read our detailed guides
Sources
- en.wikipedia.org en.wikipedia.org/wiki/LS_based_GM_small-block_engine
- chevygeek.com chevygeek.com/ls-firing-order/
- apextechnation.com apextechnation.com/articles/gm-53-v8-common-problems
- en.wikipedia.org en.wikipedia.org/wiki/BMW_N62
- europremiumparts.com europremiumparts.com/blogs/bmw-buying-guides/bmw-n62-engine-guide-reliability-co
- companyofcars.com companyofcars.com/promotions/bmw-n62-n63-valve-stem-seal-repair/
- en.wikipedia.org en.wikipedia.org/wiki/BMW_N63
- alexsautohaus.com alexsautohaus.com/bmw-n63-common-problems/
- en.wikipedia.org en.wikipedia.org/wiki/Audi_S5
- 034motorsport.com 034motorsport.com/service/audi-volkswagen-carbon-cleaning-service-direct-injecte