P0340 code. Assistance appreciated.

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Wednesday, January 23, 2019 4:38pm

My 2000 XJ (4.0 I6) threw a P0340 code (crankshaft position sensor). I replaced it and cleared the code. The CEL appeared again.

Sometimes it starts without a problem. Other times, it's a hard start and requires a couple of attempts. Once started it appears to idle normally.

Any advice is appreciated.

Thank you.

Alex

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Cruzer
2000 Jeep XJ

Join Date: November 2010

Wednesday, January 23, 2019 5:54pm

Try disconnecting the battery for 10minutes to reset the PCM computer, if nothing changes you said it hard starts ,sometimes the starter sends erratic pulses and will throw the code. Other times it's a faulty alternator but hard to diagnose that without full equipment. You can pull the starter and have them bench test it. If it's bad buy only new starters, reman starters have always failed me in 3months. Rick
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green tj
2000 jeep sahara tj

Join Date: February 2002

Wednesday, January 23, 2019 7:20pm

PCM reset didn't work. I pulled the starter. I'll keep you posted.

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Cruzer
2000 Jeep XJ

Join Date: November 2010

Wednesday, January 23, 2019 8:14pm
P0340 code

This code may be related to the relationship of the cam shaft position sensor to the crankshaft position sensor. I'm having a similar occur with my 2000 TJ. Unfortunately you have to have a more sophisticated code reader than I have to syncronize the two sensors. Anything beyond 3 or 4 degrees out and you may throw a code. It is much like setting the timing but you need a computer type tester to make the adjustment. I will let you know what happens to mine once I have it adjusted.
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Tincup
2000 Jeep Wrangler

Join Date: April 2017

Wednesday, January 23, 2019 8:52pm

* EDITED *

Rick, AutoZone tested the starter. It passed.

Kent, the synchronization you are referring to seems to be explained in the following YouTube video, is that correct?

https://youtu.be/wKdtRec9dKI (3 minutes)

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Cruzer
2000 Jeep XJ

Join Date: November 2010

Wednesday, January 23, 2019 9:59pm

I'm not sure but it seem the same. I have a cheap scanner so I can't do it. The service manual gives a "toothpick" adjustment but it did improve the issue but it still threw a code.
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Tincup
2000 Jeep Wrangler

Join Date: April 2017

Wednesday, January 23, 2019 10:01pm

Upon listening to the engine, I heard a strange noise. I put a stethoscope on the camshaft position sensor. Here's the mp3 recording.

https://drive.google.com/file/d/1fFCJz2VWVDnh8-fOeMM9MPJHm38BaU49/view

Now I'm thinking the I shoud replace the camshaft position sensor.

Any ideas?

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Cruzer
2000 Jeep XJ

Join Date: November 2010

Wednesday, January 23, 2019 10:21pm

* EDITED *

* EDITED *

I believe there is a gear on the cam that drives the thing for the sensor.  It's where the old distrubuter would have been on an older model.  I believe if you pull it out, you may find it is worn badly and that you might have to put a new cam in it and a new thing for the cam position sensor.

 

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Jeep Daddy
2004 Jeep TJ Rubicon Wrangler

Join Date: October 2014

Wednesday, January 23, 2019 10:34pm
P0340 code

I've replaced both sensors and the drive housing for the cam sensor also the spark plugs and coil assemblies. My last trial will be the syncro issue. I'm going tomorrow to try to get it resolved. I'll let you know how it works.
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Tincup
2000 Jeep Wrangler

Join Date: April 2017

Thursday, January 24, 2019 11:16am

Bud,

It looks like that part is the camshaft synchronizer for 2000-01 XJ's (and maybe other years of TJ's). Apparently, it includes the oil pump drive shaft.

I'll work on replacing it today.

Kent,

Please do let me know your results.

 

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Cruzer
2000 Jeep XJ

Join Date: November 2010

Thursday, January 24, 2019 11:41am

* EDITED *

Yes, a friend of mine is a Jeep mechanic and I remember him telling me about the noise.  That was exactly how he described that noise and those parts.  I just hope it's not your cam that needs to be replaced.  He had to replace a cam on another friends Wrangler about 8 months ago but but the guys engine was stroked and I think he flogged it all the time so no wonder why it failed.

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Jeep Daddy
2004 Jeep TJ Rubicon Wrangler

Join Date: October 2014

Thursday, January 24, 2019 11:45am

The times I've had problems it was wiring.

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JonesBones
1995 Jeep YJ

Join Date: August 1998

Thursday, January 24, 2019 1:36pm

After replacing the camshaft synchronizer, CEL remains off on the first few minutes of idling. No more strange sound exists. Engine appears to be running normally.

Thank you for your input.

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Cruzer
2000 Jeep XJ

Join Date: November 2010