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Help with TJ going into limp mode

jeepfam5

New Member
Joined
Jan 28, 2022
Messages
11
Location
High Springs, FL
We have a 2006 TJ.

The Jeep keeps going into Limp mode. We have run the codes and done the following:
Replaced PCM
Replaced cam shaft position sensor with OEM sensor twice
Replaced OPDA
Put the Jeep back in time
Checked entire wiring system and fixed any places that were damaged

We do these repairs and the Jeep runs great, until the next morning. When we go to start it, the engine light comes right back on and it goes into Limp mode. We have spent about $4,000 trying to diagnose and fix this over the last year. We know replacing the cam shaft means a new engine and we are convinced it's something other than the cam shaft sensor, we are just coming up blank.
HELP!
 

imahnu

Unorthodox
Supporting Member
Joined
Jun 1, 2021
Messages
266
Location
Houston, TX
We have a 2006 TJ.

The Jeep keeps going into Limp mode. We have run the codes and done the following:
Replaced PCM
Replaced cam shaft position sensor with OEM sensor twice
Replaced OPDA
Put the Jeep back in time
Checked entire wiring system and fixed any places that were damaged

We do these repairs and the Jeep runs great, until the next morning. When we go to start it, the engine light comes right back on and it goes into Limp mode. We have spent about $4,000 trying to diagnose and fix this over the last year. We know replacing the cam shaft means a new engine and we are convinced it's something other than the cam shaft sensor, we are just coming up blank.
HELP!
When you say OEM camshaft sensor are you talking about a true OEM sensor like what came with the Jeep or a newer Mopar sensor? The newer mopar sensors won't work. The only two that I'm aware of working besides the original ones that came on the Jeep's are the Napa sensors and the AIP sensors.

Have you removed the OPDA to get an idea of the camshaft gear? If it's not worn down then that's unlikely the problem.
 
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jeepfam5

jeepfam5

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Joined
Jan 28, 2022
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Location
High Springs, FL
When you say OEM camshaft sensor are you talking about a true OEM sensor like what came with the Jeep or a newer Mopar sensor? The newer mopar sensors won't work. The only two that I'm aware of working besides the original ones that came on the Jeep's are the Napa sensors and the AIP sensors.

Have you removed the OPDA to get an idea of the camshaft gear? If it's not worn down then that's unlikely the problem.
No, we have replaced it several times, always with OEM ones. We will definitely try the NAPA one. Anything!
We have replaced the OPDA and the cam shaft gear looks fine to us and our mechanic. Our mechanic is a Jeep guy, very good, and he is now saying new engine. We just can't imagine that it needs that with only 70,000 miles on it. Thank you for your reply!
 
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jeepfam5

jeepfam5

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Jan 28, 2022
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High Springs, FL
0344 is cam/crank related and 0340 is Pcm related. Have you gone through the wiring?
Yes, we recently went through the entire wiring harness. We fixed a couple of spots that were frayed. Once we put it back together and tested it, all was good. We drove it 200 miles with no problem. We got home, parked it and the next morning light was back on and it was back in limp mode. It's driving us crazy!
 
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Jerry Bransford

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Yes, we recently went through the entire wiring harness. We fixed a couple of spots that were frayed. Once we put it back together and tested it, all was good. We drove it 200 miles with no problem. We got home, parked it and the next morning light was back on and it was back in limp mode. It's driving us crazy!
Did you find any issues on the wiring harness on top of the engine? That's the one that leads from the fuel injectors that leads rearward and makes a bend toward the passenger side, around a threaded vertical stud at the very rear of the valve cover. That threaded vertical stud is known to damage that wiring harness by wearing through the insulation on some wires and intermittently shorting them to ground.
 
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jeepfam5

jeepfam5

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High Springs, FL
Did you find any issues on the wiring harness on top of the engine? That's the one that leads from the fuel injectors that leads rearward and makes a bend toward the passenger side, around a threaded vertical stud at the very rear of the valve cover. That threaded vertical stud is known to damage that wiring harness by wearing through the insulation on some wires and intermittently shorting them to ground.
We didn't do it, our mechanic did and that is the exact reason he wanted to do it. He found a few spots that were frayed and he fixed them.
 
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Jerry Bransford

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We didn't do it, our mechanic did and that is the exact reason he wanted to do it. He found a few spots that were frayed and he fixed them.
I wonder if your mechanic closely looked at that exact site I mentioned. It wouldn't be a bad idea to get a flashlight and you or your husband look at that particular location on the described wiring harness.
 
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CharlesHS

TJ Expert
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Jacksonville, FL, Quezon Philippines
Suggestion... while it wont cure the existing problem, but it will stop future problems with the harness and the threaded head stud (right rear corner of head near the valve cover); slip an old spark plug boot over the threaded head stud to stop the threads from further rubbing thru the harness.
Shortly after purchasing my '01 I inspected this harness for abrasions; then I placed a rubber spark plug boot over the threaded head stud to ensure the problem does not occur.
 
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jeepfam5

jeepfam5

New Member
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Jan 28, 2022
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Location
High Springs, FL
When you say OEM camshaft sensor are you talking about a true OEM sensor like what came with the Jeep or a newer Mopar sensor? The newer mopar sensors won't work. The only two that I'm aware of working besides the original ones that came on the Jeep's are the Napa sensors and the AIP sensors.

Have you removed the OPDA to get an idea of the camshaft gear? If it's not worn down then that's unlikely the problem.
We tried the Napa one, didn’t fix it. We have looked at the OPDA and it’s been fine but it’s been replaced and doesn’t fix it.
 

imahnu

Unorthodox
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Jun 1, 2021
Messages
266
Location
Houston, TX
We tried the Napa one, didn’t fix it. We have looked at the OPDA and it’s been fine but it’s been replaced and doesn’t fix it.
The only other thing I could advise you on is the AIP sensor. They have them on Amazon pretty regularly. That was the only solution I had.

I’d also say it’s very unlikely that a new 4.0 would fix the issue since the problems aren’t with the engine itself.

You could always look for a junkyard with a 05-06 Tj 4.0 and take that sensor.

Hope it helps!
 
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