When you see P0355 pop up, you're dealing with an ignition coil circuit issue on cylinder #5-sometimes labeled as coil 'E' in the service manuals. I've seen this firsthand plenty of times: your car's PCM is constantly monitoring each ignition coil, waiting for a specific signal that says, 'Yes, this coil fired.' If that signal from coil #5 doesn't show up, that's when the computer throws this code. The ignition coil's job is to deliver the spark that ignites the fuel-air mixture in the cylinder. Without it firing right, that whole cylinder is basically taking the day off. Most modern vehicles run coil-on-plug setups, so each plug gets its own dedicated coil perched right on top. That design does wonders for performance and reliability, but it also means when a single coil or its wiring fails, the computer zeroes in fast and you'll see a code like this. Sometimes, the PCM will even shut down the injector for that cylinder to protect the catalytic converter-so you might notice things get even rougher. I’ve seen this code on all sorts of cars, especially Ford, Mercedes-Benz, Lexus, and Toyota models.
DTC P0355
5282
6 minutes of readingCauses of obd2 code P0355
From my time under the hood and what the manuals back up, these are the usual suspects when you’re staring at a p0355:
- The ignition coil itself on cylinder #5 goes bad. Honestly, this is the number one reason-they just wear out with age and heat cycles.
- Wiring or connector issues feeding that coil. I can't count how often I've found corroded, cracked, or rodent-chewed wires cause headaches.
- Problems inside the PCM, like outdated software or, though it’s rare, an internal failure.
- On some cars-especially certain Fords-an open or short in the circuit that drives the coil can be the trigger.
In my experience, most of the time it’s the coil or the wiring, but you’d be surprised how a stubborn PCM can be the culprit if everything else checks out. For those searching dtc p0355 ford, this is often what you're dealing with.
Symptoms of obd code P0355
Once this code hits, you’ll probably notice a few things right off the bat. That check engine light won’t just turn on-it might start flashing, and that’s never good. Expect a rough idle, engine shaking, or even a sharp misfire-especially when you try to accelerate. You might feel a big drop in power or sluggish response when you put your foot down. Every now and then, if you catch the problem early, you might not feel much-though that’s pretty rare from what I've seen. Let it go, and the symptoms will get worse in a hurry. Folks searching dtc p0355 mercedes benz are usually dealing with these exact issues.
Diagnosis steps for P0355
Here’s how I’ve learned to chase down a p0355, step by step:
- First, always start simple. Pop the hood and eyeball the ignition coil on cylinder #5. Look for cracks, burn marks, or loose connections. Sometimes just giving the connector a gentle wiggle can uncover a hidden problem.
- Next, follow the wiring. I’ve seen wires get brittle, melted, or chewed up by mice more times than I can count. Don’t forget to check for corrosion or bent pins at the connector. A second set of hands to move the wires while you watch for changes can make life a lot easier here.
- If everything looks solid, swap the suspect coil with one from a different cylinder. Clear the code, fire up the engine, and see if the code jumps to the new location. If it does, bingo-the coil’s toast.
- If the code sticks to cylinder #5, break out your multimeter and check the circuit. You want to see continuity where it belongs, and no shorts to power or ground where there shouldn’t be.
- Don’t overlook the spark plug itself. A bad plug can create symptoms almost identical to a bad coil, and it takes just a minute to check.
- If none of that solves it, you might be looking at a PCM issue. It’s rare, but if you’ve checked everything else, use a good scan tool to look for software updates or internal PCM faults.
I always recommend starting with the basics before diving deep into wiring diagrams or swapping computers. People looking up dtc p0355 lexus usually end up following these same steps.
Common Mistakes with dtc P0355
A classic mistake I see-folks instantly replace the ignition coil without checking the wiring or even looking at the spark plug. That’s a quick way to burn through cash if the real problem’s a busted wire or a crusty connector. Another one? Overlooking a vacuum leak, which can easily mimic misfire symptoms. And don’t skip the coil-swap test; too many people assume the code has to mean a bad coil. Always, always rule out the simple stuff first. It’s a trap I see folks searching dtc p0355 toyota fall into all the time.
Seriousness of P0355 trouble code
This is one of those codes you don’t want to mess around with. Driving with a misfire can fry your catalytic converter-one of the priciest parts to replace. You’ll also notice your gas mileage nosedive, and you could find yourself stranded if the issue snowballs. If that check engine light is flashing, things are already heading south. Misfires dump raw fuel into your exhaust, which overheats the cat and can even lead to engine damage if you keep ignoring it. I can't stress it enough: p0355 means urgent business-get on it before you’re looking at a much bigger repair bill.
Repair options for P0355 engine code
From my hands-on fixes, here’s what usually gets p0355 sorted:
- Swap out the faulty ignition coil on cylinder #5.
- Fix or replace any damaged wiring or connectors heading to the coil.
- If the spark plug is worn out or fouled, replace it while you’re in there.
- If, after all that, the PCM is still causing trouble, you may need to update or replace it-but that’s pretty rare.
- Address any vacuum leaks you found during your checks.
Once you’ve made the repair, always clear the code and take the car for a spin to make sure everything’s truly fixed. The phrase p0355 inevitably comes up in the shop when talking about these types of repairs.
Conclusion
Bottom line: P0355 tells you cylinder #5’s ignition coil signal isn’t making the grade. It’s a high-priority code, because it hits your engine’s performance and can lead to some expensive damage if you sit on it. Start with the basics-inspect, swap, and test before you start throwing parts at it. Nine times out of ten, a new coil or fixing a broken wire gets you back on the road. Don’t drag your feet on this one; the risk just isn’t worth it. Get your car checked and fixed quickly-for your own safety and to keep your ride running strong.
