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P0353 on 03 Jeep Liberty


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Hey Scotty, I have an 03 Jeep Liberty with the 3.7 V6. I recently drove it about 100 miles before filling it up and parked it for a day. Upon going to start up again I had a CEL. I scanned it, and I had the codes P0303 and P0353. I immediately tried a coil swap, but it remained on Cylinder 3. I checked spark plugs, and they're great, practically new. I did a compression test, it passed with flying colors. I checked the coils for resistance, they all appear to be fine. I started it up again later, and had two more codes for a random misfire and a misfire on cylinder 4. Im suspicious of bad gas affecting all the cylinders. Is there anything else to try? Let me know. Thanks 

1 Answer

Bad gas wouldn't set an ignition coil circuit code.


You're right. I noticed my cyl 3 coil was literally melting. Threw a new one in its place, and it melted too. Evidently I have a short somewhere. Any tips to troubleshoot the short?

A melting coil seems more like an Open in the secondary side of the coil circuit. The secondary coil is producing somewhere around 40,000 volts and it needs a path to Ground. It gets that path to Ground through the spark plug when it jumps the gap. If it has no path to Ground it's soon going to melt the coil
Since almost all of the secondary side of the coil circuit is inside the coil (your coils are mounted directly on the spark plugs) I'd be wondering if a faulty spark plug is the problem.
I wouldn't swap spark plugs I'd replace it with a new one because if the spark plug is the problem you can melt another coil