Causes for P0359
From experience, the most common reasons for a P0359 code are usually electrical in nature. Here’s what I see most often:
- A short to voltage or ground in the wiring for coil #9
- An open circuit (broken wire) in the coil driver circuit
- Loose or corroded connections at the coil or broken connector locks
- A faulty ignition coil itself
- A problem with the engine computer (PCM), though this is less common
In cases like this, wiring and connection issues are usually the main culprits, but a bad coil isn’t rare either.
Symptoms of the P0359 trouble code
Let’s talk symptoms. When P0359 sets, here’s what you’re likely to notice in the real world:
- That check engine light will come on-almost always your first clue
- The engine might stumble, misfire, or run rough, and sometimes it feels worse when you’re accelerating hard
- You might find you’ve lost some power, or the car hesitates when you ask for more
- Every now and then, the misfire will come and go, just to keep things interesting
If you’re picking up on any of these, don’t put it off. Leaving it unchecked can turn a small fix into a much bigger (and pricier) headache.
Diagnosis and testing for the P0359 code
Here’s how I usually tackle a P0359 code, step by step:
- First, I check if the engine is currently misfiring. If it’s running fine, sometimes the problem is temporary, but it’s still worth investigating.
- I start with a visual inspection of the wiring and connector at coil #9. Look for broken wires, loose connections, or anything rubbing or pinched. Don’t forget to check for corrosion inside the connector.
- If I spot anything suspicious, I’ll wiggle the wiring gently while the engine is running to see if the misfire comes and goes. That’s a surefire way to find a bad connection.
- If the wiring looks good, I’ll unplug the coil and use a multimeter set to frequency (Hz) to check for a signal from the PCM. You should see a reading between 5 and 20 Hz if the computer is working right. If you get a signal, the coil is probably bad-swap it with another cylinder to confirm.
- If there’s no signal, I check for voltage in the driver circuit at the coil connector. If you find voltage where there shouldn’t be, there’s likely a short somewhere in the harness.
- If all the wiring checks out, I’ll test for continuity between the PCM and the coil. No continuity means there’s a break or short in the wire that needs fixing.
- Finally, if everything else passes but the coil still isn’t firing, the PCM itself might be at fault. That’s rare, but it does happen.
It’s better to have someone assist you with these checks, especially when testing live circuits.
Common Mistakes when fixing obd2 code P0359
Honestly, one of the biggest mistakes I see is jumping straight to replacing the ignition coil without checking the wiring first. Another common slip-up is overlooking a loose or corroded connector-sometimes all it takes is cleaning or tightening a connection. People also sometimes forget to swap coils between cylinders to see if the problem follows the coil, which is a quick and easy test. Skipping these steps can lead to wasted time and money.
Seriousness of the P0359 engine code
This isn’t something you want to ignore. A misfire on one cylinder can quickly lead to raw fuel entering the exhaust, which can damage your catalytic converter-a very expensive part to replace. Plus, driving with a misfire can cause poor performance, higher emissions, and even engine damage over time. Things can go south quickly if overlooked, so don’t put this off for later. Your safety and your wallet are both at risk here.
How to repair obd code P0359
Here’s what I typically do to fix a P0359 code, based on what the diagnostics show:
- Repair or replace any damaged wiring or connectors at coil #9
- Replace the ignition coil if it’s found to be faulty (after confirming with a swap test)
- Fix any shorts or opens in the coil driver circuit between the PCM and the coil
- If the PCM is at fault (and all wiring is confirmed good), replace or reprogram the PCM as needed
Always double-check your work and clear the code after repairs to make sure it doesn’t come back.
Conclusion
Wrapping up, when you see P0359, you’re looking at a problem with the ignition coil circuit for cylinder 9-usually a wiring snag, a bad coil, or once in a while, a PCM issue. Don’t sit on it. Diagnosing early can save you a big pile of cash and keep your ride running strong. Start simple: check your wiring and connections, make sure the coil is up to snuff, and leave the computer for last if you have to. Trust me, quick action now means you’ll avoid bigger trouble down the road.
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