P0340 code on TJ

VortecJeep

VortecJeep

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Joined
Aug 24, 2005
Location
Concord, NC
Long story short...4.0 liter 2000 Wrangler 107,000 miles. Engine is running fine, then suddenly acts like it misses big time. Speedo goes crazy. After about a second, it is done. Also had trouble starting several times. Also the engine speeds up to about 2000rpm sometimes when I put it in neutral coming to a stop. It gave a check engine light. Code was P0340, Camshaft position sensor circuit. Due to time restraints, I took it to the jeep dealer last week instead of working on it myself. The code must have been cleared out by Autozone or something, because the dealer said they didn't find any codes. I told them the code. They replaced the camshaft position sensor, then said the light came on when they pulled it out of the garage. They then changed the Crankshaft position sensor. I brought it back home. Monday morning, trouble starting, the light came on, same thing. I checked the code at Autozone before taking it to the dealer. Took it back to the dealer thinking maybe I had gotten a bad sensor and they said the code was not there. I picked it back up (being the nice guys they are, they didn't charge me for the second time of them doing nothing).

Now, $410 poorer, I have two new sensors, but the same symptoms. I guess now I will make the time to fix it myself. Anyone else had this problem? Anybody got a shop manual for a TJ?

Also, for future use, anybody know of a good honest mechanic in the Concord/Harrisburg area?
 
good chance it's an 02 senser, i live in the university area if you wanna swing by wednesday evening i'll take a look at it for you. i'll pm you my number.

nic-
 
Do a google search on Jeep p0340. Lotsa people have the same problem. Only a few have posted fixes. One guy fixed his with a coil and a tech suggested that other sensors are shorted and "pulling down" the crank and cam sensors.
 
A long time ago, my 4 banger was acting like that. It would even just go dead at times.I chacked nearly everything.
Turns out, it was the wire on the o2 sensor.It was to long and would double around and had kind of melted to the exhaust pipe a little. Just for kicks, go check that.
 
Last night I looked at the wires going to both O2 sensors, and the wires do not appear to be damaged. Is there any way to test an O2 sensor? I understand how an O2 sensor could make an engine run rough, but I don't see how it could cause it to have a hard time starting.
This morning it was hard to start and this afternoon, it did that thing again where is misses or bucks or whatever and the gauges go wacky. I also noticed this time that when it did it, the "Check Gauges" light came on, but then went out as soon as it started running right again. No check engine light right now. Battery and alternator are fine, I had them tested.
 
I've unplugged one to test it out, it should run OK without it, just have the CE light on. I really have no idea whats going on with that one.
 
Does anybody think it could be the coil? It has the coil-ignition that is a strip across the top of all the spark plugs instead of individual plug wires. It has given me a hard time starting, but no check engine light in the past few days and has missed while driving.
 
When is the last time it had a REAL tune up ? Plugs, wires, cap, rotor.

Don't over look these, as they can and will give you many of the same symptoms. If it was recent, did you use QUALITY parts ?
 
Blkvoodoo said:
When is the last time it had a REAL tune up ? Plugs, wires, cap, rotor.

Don't over look these, as they can and will give you many of the same symptoms. If it was recent, did you use QUALITY parts ?
Click to expand...
2005 I think, but it was just spark plugs. This engine has not plug wires or distributor cap. It has an ignition-coil that mounts on top of the the 6 spark plugs that has the coils built in. I think it could be that or the fuel strainers in the gas tank, there is no fuel filter, just two strainers from what I have researched.

It completely died on me this morning going to work. I got to to start back up and it ran long enough for me to turn around and died again.
 
I had the same problem with my 97 TJ 4.0, turned out to be the throttle position sensor. I did a complete tune up, plugs, wires, cap, etc. till I figured out it was the TPS. Replaced the sensor but after I would go wheeling, the code would come back with the same syptoms of knocking and engine cutting out. I went through 3 of them in about 4 months. Never really knew why but was told that if moisture gets inside the sensors it will fry them. So now I avoid the deep mud holes to save me the extra 100 bucks for the sensor and headache. Haven't had a code thrown since.
 
I thought I'd let everyone know what the solution was in case anyone else ever has the same issue. After the cam position sensor and crank position sensor were replaced, the check engine didn't come on anymore, but the same symptoms still existed (hard to start, missing, and finally completely shutting off) and actually continued to get worse. I don't know about pre-2000 TJs, but mine is a 2000 TJ and doesn't have your typical distributor cap/spark plug wires and coil, instead it has an ignition coil which is all one piece that attaches on top of the spark plugs and has 3 coil packs built in. I changed that out and have driven almost 70 miles thus far and have experienced no more problems. Hopefully this will save someone else the trouble I went thru.
 
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