2003 TJ Sport 4.0 misfiring and code P0353

mcammara

mcammara

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Hi everyone - first of all, I want to thank Chris and all the members for the great contents in this forum.

12 months ago, I decided to become a TJ owner buying a Manual 2003 Sport 4.0.
When i was looking for the right car, my mechanic kept saying to avoid buying Jeeps here in Australia as Jeeps is the acronym of "Just Empty Every Pocket".
Since this has been my favorite car since I was a kid, I ignored the mechanic and went ahead buying a TJs.

It has been a great ride but few weeks ago the car started misfiring and the code P0353 appeared.
I'm not very familiar with the mechanics of a car so I left it with my mechanic, he said he replaced the full coil pack and also checked all the wiring saying that it's all fine.
He's now saying that the only thing left that could cause the issue is the PCM.

I wanted to get your opinion before getting a new PCM as here in Australia they are very expensive.
Would be great to hear what you suggest as I'm missing my Jeep badly.

Thanks in advance.
Marco
 
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mcammara said:
Hi everyone - first of all, I want to thank Chris and all the members for the great contents in this forum.

12 months ago, I decided to become a TJ owner buying a Manual 2003 Sport 4.0.
When i was looking for the right car, my mechanic kept saying to avoid buying Jeeps here in Australia as Jeeps is the acronym of "Just Empty Every Pocket".
Since this has been my favorite car since I was a kid, I ignored the mechanic and went ahead buying a TJs.

It has been a great ride but few weeks ago the car started misfiring and the code P0353 appeared.
I'm not very familiar with the mechanics of a car so I left it with my mechanic, he said he replaced the full coil pack and also checked all the wiring saying that it's all fine.
He's now saying that the only thing left that could cause the issue is the PCM.

I wanted to get your opinion before getting a new PCM as here in Australia they are very expensive.
Would be great to hear what you suggest as I'm missing my Jeep badly.

Thanks in advance.
Marco
Click to expand...
Is your mechanic a jeep mechanic?
PCM is usually an Auto problem but not exclusively.
I am sure some in US will jump in.
PCM,s are expensive everywhere not just in Australia wranglerfix is the man to talk to when they wake up in US.

https://www.engine-codes.com/p0353_jeep.html#causes
 
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mcammara said:
Hi everyone - first of all, I want to thank Chris and all the members for the great contents in this forum.

12 months ago, I decided to become a TJ owner buying a Manual 2003 Sport 4.0.
When i was looking for the right car, my mechanic kept saying to avoid buying Jeeps here in Australia as Jeeps is the acronym of "Just Empty Every Pocket".
Since this has been my favorite car since I was a kid, I ignored the mechanic and went ahead buying a TJs.

It has been a great ride but few weeks ago the car started misfiring and the code P0353 appeared.
I'm not very familiar with the mechanics of a car so I left it with my mechanic, he said he replaced the full coil pack and also checked all the wiring saying that it's all fine.
He's now saying that the only thing left that could cause the issue is the PCM.

I wanted to get your opinion before getting a new PCM as here in Australia they are very expensive.
Would be great to hear what you suggest as I'm missing my Jeep badly.

Thanks in advance.
Marco
Click to expand...
Did you replace all the plugs yet?
Next Take check the crank position sensor.
I dont think its the PCM.
 
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Guys - thanks a lot for the quick responses.

Fishtaco said:
Is your mechanic a jeep mechanic?
PCM is usually an Auto problem but not exclusively.
I am sure some in US will jump in.
PCM,s are expensive everywhere not just in Australia wranglerfix is the man to talk to when they wake up in US.

https://www.engine-codes.com/p0353_jeep.html#causes
Click to expand...

No, the dude is a normal mechanic. Not a Jeep one. I live in Byron Bay, 700km from Sydney and 300km from Brisbane.
The only Jeep mechanic around seems to be the Jeep service center, but not sure if they check cars pre-2007.
So, is it less likely to happen in a manual car?

myjeep3 said:
Did you replace all the plugs yet?
Next Take check the crank position sensor.
I dont think its the PCM.
Click to expand...

Nope, he didn't replace the plug in my understanding. He just checked them.

Maybe I can gather a few answers on this thread and showing them to him before even thinking to spend heaps of money to replace the PCM.

Also wanted to ask. How safe it is if I move it from a mechanic to another and drive it for 50km?
 
mcammara said:
Guys - thanks a lot for the quick responses.



No, the dude is a normal mechanic. Not a Jeep one. I live in Byron Bay, 700km from Sydney and 300km from Brisbane.
The only Jeep mechanic around seems to be the Jeep service center, but not sure if they check cars pre-2007.
So, is it less likely to happen in a manual car?



Nope, he didn't replace the plug in my understanding. He just checked them.

Maybe I can gather a few answers on this thread and showing them to him before even thinking to spend heaps of money to replace the PCM.

Also wanted to ask. How safe it is if I move it from a mechanic to another and drive it for 50km?
Click to expand...
Plugs are cheap, why not replacing them if all coils where replaced, and you have that code. ??
Why he is jumping to the PCM? What troubleshooting have he done to conclude that its a bad pcm? Knowing more would help.

You can drive it with no issues. May feel sluggish n rough.
 
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Spark plugs is where you start then CPS he probably plugged in his OBD11 reader, ask him what it diagnosed or if he just looked up the code.
 
The P0353 code can be caused by the coil pack, but not exclusively.
I would examine the wiring harness going from the ECU to the coil pack for bare insulation shorting to ground.
Couldn't hurt to remove the three 32 pin harness connectors for the ECU, examine the pins and clips for oxidation and firmly snap the harness connector into the ECU receptacles.
Examine the communications harness that is routed behind the valve cover and curves around a threaded head stud on the drivers side. This harness rubbing thru the split wire loom and wiring insulation is a known problem that can cause a wide variety of engine operating problems.
You can drive your Jeep to another mechanic, but the Jeep could stop running if the short becomes continuous.
 
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Just Empty Every Pocket is a worldwide saying but I dont think your mechanic should be saying it while he is charging you to fix it lol
I think the problem in Australia is everyone is a Toyota fanboy and people maintain their jeeps with cheap non original parts which TJ,s do not like and quite often do not work at all.
You have to be prepared to buy or import the correct parts or find a Wrangler/jeep/4x4 mechanic closest to you, most of these guys have been fixing and owning jeeps for many years
 
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myjeep3 said:
Plugs are cheap, why not replacing them if all coils where replaced, and you have that code. ??
Why he is jumping to the PCM? What troubleshooting have he done to conclude that its a bad pcm? Knowing more would help.

You can drive it with no issues. May feel sluggish n rough.
Click to expand...

Totally Agree - I think he just checked the plugs and the wires. Will get more information on Monday.
Maybe I get him to post here what he actually did.
Really hope is not the ECU, cause will have to get one imported from the US for sure.

Fishtaco said:
Spark plugs is where you start then CPS he probably plugged in his OBD11 reader, ask him what it diagnosed or if he just looked up the code.
Click to expand...

The code reader is saying P0353.
Agree, here everyone is a Toyota fanboy and people have no much clue of jeeps.
If you know anyone reliable between Ballina and the Gold Coast let me know.
 
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mcammara said:
Totally Agree - I think he just checked the plugs and the wires. Will get more information on Monday.
Maybe I get him to post here what he actually did.
Really hope is not the ECU, cause will have to get one imported from the US for sure.



The code reader is saying P0353.
Agree, here everyone is a Toyota fanboy and people have no much clue of jeeps.
If you know anyone reliable between Ballina and the Gold Coast let me know.
Click to expand...
Dazza is from Sydney and has owned a couple of TJ,s since new, go to reginal TJ forums then go to Australia and he usually picks up on a topic or you can message him. We have at least 5 non Dealer jeep repairers in and around Perth so there are bound to be more in NSW and Sydney.
 
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Hi everyone - keeping you updated on this P0353 nightmare.

The same mechanic replaced the ignition coil pack and the spark plug, tested the wiring once again and then tried another ECU of the same car in my TJ.

He mentioned that the car is running for 5 minutes, before switching off because the key is not programmed for that ECU.
He also said that this test helped him confirming that the issue is coming from ECU.

Now he's thinking to send the ECU to a repair centre.
I wanted to check with you if all this makes sense or if he's bullsh****ing me.

What's your view?

Thanks in advance.
 
Weasellee said:
There’s a guy on here somewhere that tests and repairs these …. @Chris do you know who it is?
Click to expand...
@Wranglerfix is who does that.

@mcammara exactly what brand and model # spark plugs are installed? Some spark plugs that some guides say are appropriate are known to cause misfires with the coil rail ignition system.
 
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Thanks - these are the new spark plugs that we just put in. They seem the right ones?

https://www.ebay.com.au/itm/NGK-Nic...d=link&campid=5337789113&toolid=20001&mkevt=1
The one that were fit previously were not the right one and since I just got the car no one realized.

I wish @Wranglerfix could fix mine, but I'm in Australia.

Jerry Bransford said:
@Wranglerfix is who does that.

@mcammara exactly what brand and model # spark plugs are installed? Some spark plugs that some guides say are appropriate are known to cause misfires with the coil rail ignition system.
Click to expand...
 
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@mcammara I ship around the world snd can repair your Ecm for you. What is the part number on yours? Send me the vin number as well and I will check what software it takes.
 
Wranglerfix said:
@mcammara I ship around the world snd can repair your Ecm for you. What is the part number on yours? Send me the vin number as well and I will check what software it takes.
Click to expand...
What a legend. My mechanic sent it to someone locally.
I'm still skeptic that this is the real issue as the mechanic is not a dedicated Jeep guy.
I'll definitely keep you posted and will send the ECU in case they don't fix it.
Thanks in advance.
 
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The 2003 is made by JTECH. There is a certain way to open them and it is very easy to destroy the processor if you venture too far in. Get me your part number before your computer is blown to Cairns and back.
 
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