Why am I getting the p0352 code on my Jeep Wrangler TJ?

Models Wrangler TJ (1996-2006)
1

I drive a 2003 Wrangler TJ Sahara with a 4.0L engine, automatic transmission, and 105,000 miles.

This problem started about six months ago when I noticed my fuel mileage got really bad. I used to get 300 miles on a full tank, but suddenly I was only getting 200 miles. I checked for leaks and drove more carefully, but it didn’t help.

Two weeks ago, I hit a pothole that shook my car hard, and the check engine light (CEL) came on. My Jeep started idling roughly and lost power. I pulled into a parking lot and turned it off. After two minutes, I started it again, but it was still idling rough, and the CEL was still on. I turned it off for a few hours, then restarted it. The CEL was still on, but the idle was back to normal. After driving it a few more times, the CEL went away. I thought it was a one-time issue, but I checked for error codes with an OBDII scanner, and it showed a p0352 code (ignition coil). After searching online, I found that bad spark plugs could be the cause.

Since I had never changed my spark plugs, I decided to replace them. They were worn out, so it was a good call. My fuel mileage improved, and the engine ran smoothly again.

I thought the problem was solved until last night when the p0352 code came back with the same rough idle and power loss. It happened during a three-point turn. When I switched from reverse to drive, the CEL came back, and I lost power. Luckily, I was only 500 feet from home, so I made it back.

I’ve been searching online all day for answers, but I’m getting lots of different suggestions, and I don’t want to spend a ton of money replacing parts if I don’t have to.

Based on the symptoms, it could be:

Crankshaft position sensor
Camshaft sensor
Ignition coil rail
PCM (Powertrain Control Module)
Wiring issues
Could it be the crankshaft position sensor? I heard the car might not even start if that’s the problem. Is that true?

Could it be the camshaft sensor? I’m not sure.

Could it be the ignition coil rail? I’ve heard that when these fail, they fail completely, without intermittent issues. Is that true?

Could it be the PCM? I’m unsure about that too.

How about the wiring? Could it be a short or bad connection? How do I check that?

I really don’t want to go to a dealer, but I only have a few tools. Any advice would be appreciated.

6 Likes
2

I haven’t experienced that code before, but I can confirm that a few inactive cylinders could cause the problems you’re having. I recommend doing a compression test, especially on cylinders 2 and 5. If needed, follow up with a leak-down test.

5 Likes
3

You replaced the spark plugs but didn’t change the ignition coil after 105,000 miles? Maybe you should consider a full tune-up. Since you’ll have the spark plugs out, doing a compression test would be a good idea to check for any internal issues.

4 Likes
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It sounds like there might be an issue with the wiring. Try moving the wiring harness connected to the PCM where it connects to the coil rail. If this makes the problem come and go, you should check the harness for any damage. Pay special attention to where the harness goes from the firewall to the engine. Bolts from the firewall could damage the harness if it touches them, causing various issues depending on which wires are damaged. Specifically, check the dark blue/tan wire from the coil pack to the PCM, which controls the #2 coil driver for cylinders 2 and 5, related to the P0352 code. Make sure this wire isn’t damaged and is properly connected in the white connector at the PCM.

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It sounds similar to what mine was doing—an intermittent misfire with the check engine light coming on. The code was for a misfire, and it turned out to be a bad spark plug wire. Replacing it with a tune-up fixed the problem.

2 Likes
6

I agree with @Mason . The problem is with the cylinder that’s firing during the compression stroke when coil 2 is active. Check the wire from the PCM to the coil rail first. After that, things can get expensive, so start with the simplest and cheapest fixes.

1 Like
7

Sounds like a wiring problem or a coil going bad.