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Discussion Starter · #1 ·
I'm running down the much-feared P0344 error that struck my rig down 30 miles away from my Death Valley vacation.

I've been through all the threads...harness bypassed, new cam and crank sensors, etc. Actually after replacing the cam sensor on the road, took it to the dealer up in Nevada. They cut my harness and bypassed the wiring - to no avail. Dragged it home on a tow bar..

I got a Hantek auto oscilloscope and have recorded the traces capturing the moment the error code trips. Scope shows a perfect cam and crank signal going into the ECU...no change or variation.

Betting that I need a crank/cam relearn and then a sync...but I also am guessing the dealer had done that (I don't knAow). Before I pay another dealer to do so...I'm making sure my systems are in order.

So I need a good cam/crank waveform to compare to. Can't find anything on the Web for the 2005/2006 Wranglers.

Anyone have one handy? Mine is shown below... Thanks!

75798
 

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Where are you located, maybe someone local can swing by for a rreading.
 

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Bad ECU?
 

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For the record, you said it first! WranglerFix for 05’s and 06’s. Call them in Florida or PM them on here. Calling is probably the easiest.
 

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Discussion Starter · #5 ·
Yes...my money is on the ECU, but it's also the most expensive thing to replace other than the camshaft and I just did one 18 months ago.. It's a crummy unit if you ask me...

There are legions of folks who have swapped ECUs and still have the issue so I want to exclude as much as I can.

With a swapped OPDA and 162,000 miles, the first recommendation is to take to to a dealer to execute the cam/crank relearn (also called for in the FSM) and then a cam synch. Dealer charges me $125 just to connect to my heap, so again, I want to make sure everything is correct before I do that.

Could be my cam is shot as well, or my timing chain...that would reveal itself comparing scope traces.

Just want to compare the timing of the two signals against a known good. There are libraries of these things on the Internet but I can't find one for the Jeep 4.0. The Picoscope library is subscription only.

I'm in Gilbert, AZ if anyone is local with an '05 or '06 Wrangler. Or with a DRB so I can execute the relearn.

One frustrating thing (I think to all of us) is there are a couple dozen threads of people fighting this error code for years and then they go silent. I find it hard to believe they junked their rig, but there's not a lot of info on what people have done that was successful.

I'll post up what the end result is...I will win!!!
 
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Discussion Starter · #6 ·
$1,149 for a manual...$549 for an AT...guess what I got? Yep...manual. Ouch!

Though my dealer unit was $1,300....

I'll be doing some additional validation before I got that route...
 
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The good news is that your PCM is not like all the others in that it is an 05. Maybe I was coming across as too cute. Call WranglerFix and talk to them. Go to their site. Your 05 and 06’s are unique.
 

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Going from memory... You are getting a waveform that looks correct. Weather it is timed properly I cannot say. Out of time is the same as it always has been. Do you have spark? Are your plugs wet? Is it cross firing? Don't let the internet get you ahead of basics. You are getting a cam and crank signal.
Lift the front of the coil rail when cranking does it spark snap?
You. can check the cam sensor timing with a screwdriver at TDC. The FSM gives a procedure for the opda installation.
 

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Discussion Starter · #9 ·
So...this is a running rig. No issue with spark, fuel delivery, etc. When a P0344 code is thrown (camshaft sensor intermittent), it goes into limp mode and won't rev above 2500.

It is not a P0340 (which it had when the problem first started) which is no camshaft signal. The new CPS fixed that.

We were cruising at 70 when it went into limp mode...first time since I bought it new.

Then the dealer had it, butchered the wiring and and after 32 miles it went back into limp mode. I limped it within 250 miles of home and then went and retrieved it via towbar.

OPDA is installed per the factory shop manual. This was a troubleshooting effort as it's a very weak link in 2005/2006.

HOWEVER the last step of the factory manual is:

  • Connect DRB scan tool to data link connector. The data link connector is located in passenger compartment, below steering column.
  • Gain access to "CAM/CRANK RELEARN" screen on DRB scan tool.
I don't have "free" access to a DRB and I'm not willing to pay $125 every time I change a component as part of the troubleshooting effort.

This is also different than a CAM Sync which can be done with an aftermarket tool.

For those familiar with this issue on this model year:

1. OEM sensors are not available and are considered suspect at the end of the production run
2. Aftermarket sensors are considered junk and considered suspect.
3. I have the OEM plus a Crown plus a Durlast sensor. One person tested mutliples and found wide variation in pulse width between them.
4. Wire harness was the source of 2 fixes - mine is bypassed on the signal lead.
5. Camshaft gear wear caused by faulty OPDA is very common
6. Sloppy camshaft driving the OPDA can lead to the sensor wandering outside of an acceptable timing range.
7. Even perfectly clocked at TDC, there is slop in the rotation and you can turn the body within a few degrees
8. This can also bring the timing outside of the range the ECU can correct for.
9. The crank sensor, cam sensor, MAP sensor and VSS all share common wiring (+5voltages, grounds)
10. A short or drop in reference voltage will shut down all of these sensors...the Cam reports first
11. The Camshaft sensor goes to P0344 after 2 revolutions of the crank without a signal.

So...why the oscillocope?

The ECU is reporting a intermittent Camshaft signal.

The ECU is expecting a positive voltage at very specific positions of the crankshaft. It can correct or be calibrated for a couple of degrees difference. If it sees zero at a time it's expecting a pulse...either because it's missing or it's out of time...it will call it intermittent.

If it stays zero it will call it missing.

Test one was to see if there was a signal when it was reporting intermittent.

There IS a signal...and no question that it's correct by itself - the pulses match the tone wheel in the OPDA.

So looking for the relation of the signal to the crankshaft. That is why I want a known good reference.

I also want to pick the sensor that has the correct width.

If I am presenting an in-time, correct signal to the ECU, then I'll pay for the relearn (they can clock the OPDA ever so slightly to bring it in). And if that fails...then it's new ECU time.

If I have an out of time signal, I can try to bring it in by clocking the OPDA slightly or look more closely at the camshaft gear, etc. With ECU, camshaft and dealer visits on the horizon, a quick verification of cam/crank timing is free and appropriate.

So...this isn't an unusual request. A quick search shows a number of issues that are successfully resolved in this manner, across a whole host of vehicles.

Type in code P0340/0344 and 05 or 06 Wrangler and a search on this very forum and you will see long running threads on this issue for these specific years... And the participants in the thread are some of the most respected folks on this forum. I've looked into and have done the work prior to posting this and am well into the troubleshooting.

One last common theme is cold weather failures. I don't have this issue. Mine crops up 30 mins to an hour down the road regardless of outside temp. Sometimes its clear at startup and sometimes its still indicating but not in limp mode.
 

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You said that a fix in the wire harness fixed a problem. Is it possible the wires before the fix grounded out or did bad things to each other? I had injector wires touch from age and fried my PCM. I’m wondering if they fixed the wiring, but maybe the PCM was still compromised. I’m curious that they went upstream from whatever component to the wiring harness. Upstream from the harness is the PCM.
 

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Discussion Starter · #11 ·
I may have phrased that wrong...I tend to prattle a bit...

I do believe it's possible the ECU is having the intermittent issue, but I think it is more likely internal - cold solder joint on pin 34 or a temp/vibration sensitive component. I wish loaner ECUs were viable!

The original code was P0340 and P0344. Code was read on the road at Autozone, procured and installed the new sensor in the parking lot.

That cleared the P0340 but the P0344 returned in about 20 minutes.

Since I was on the road without diagnostic resources - I took it to the dealer. They had it for 2 days and cut and bypassed all 3 wires to the sensor with a caveat. The signal wire is point to point to the ECU, so that's out of the equation. The ground and +5volts is shared with the other sensors, so while they ran new wires from the sensor connector, they had to ties these two back into the harness up by the ECU, or the other sensors wouldn't have power. So not a perfect bypass.

Problem returned and I had to get back home (work being what it is), so even though the code returned, I limped it home.

Now, on the assumption that harness had an issue - the options are:

1. If the ground wire shorts against the chassis, it may induce noise, but it's actually creating "more ground'.
2. If the +5 grounds, then all sensors lose power
3. The signal wire for the CAM sensor is now point to point with the ECU so it's eliminated as part of the problem.
4. If the ground is lost then we lose the 5 volts as well.

I proceeded to verify grounds and also added temporary grounds to the sensor itself. From each of the 4 sensors spliced into the common ground I have 0.2 ohms resistance to ground.

Then, with the oscilloscope, I'm monitoring the 5 volt rail voltage at the sensor, along with the sensor signal.
If the 5 volt shorts, the sensor voltage will fluctuate or be lost and the sensor signal will degrade or go away.

That isn't occurring. When the ECU flips the code, there is no change in the CAM signal and the 5 volts isn't fluctuating.

Regarding the Crank sensor - and the other 2 (MAP, VSS) - if any of these short internally they can take down the 5 volts and throw a CAM code. That's the reason the code doesn't always point to the faulty component.

So crank and MAP have been replaced as well, before I got the scope. As some have said, sometimes it's cheaper to replace than to test and they only took minutes to swap

That isn't true of ECUs and camshafts...

I have the MAP and Crank sensors back in and the new ones as spares since they didn't solve the issue.

Now that I have the scope, I've been able to determine that nothing is happening with the ground or the 5 volts.

Thank you for the input!...

Most of the folks who've had this problem are probably long onto other vehicles. Not giving up on a LJ though! Too hard to come by to risk sellers remorse!

Still have folks asking me if I'll sell...
 

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It may not be the PCM, but if it is, you'll be chasing things that don't pan out into eternity. Just do my heart a favor and don't put WranglerFix with the PCM puppy mills. I'm not paid by them in any way. I've just seen 05 and 06 Wrangler owners go from complete torment into giggles as they experience healing.
 

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When I bought my LJ I noticed a wire had been bypassed in the PCM wiring harness - the wire disappeared somewhere on top of the transmission.
 

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I have a bypass going to #2 injector. That was an attempt by the mechanic to fix the issue. When he saw that didn’t work, he got frustrated and got a replacement PCM on his own. I told this story in another thread. It was the PCM.
 

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Discussion Starter · #15 ·
Interesting John - Sharing the same +5 and ground is the VSS which is at the back of the transmission..or top of the transfer case I think. Anyway...all on the same circuit.

That's where the speedometer recalibrator that I had instructed me to tap into the VSS sensor. When I was running that, I spliced towards the ECU instead.

About 3 years later my Jeep started randomly dying on the freeway and the fuel guage, speedo and tac all pegged. ECU triggered the rev limiter thinking it was overspeeding.

Disconnected that unit and problem went away. Don't know if it picked up something induced along the path I picked.

Along the same lines if one of the wires was shorting to the VSS...that may have been a reason for the bypass.

One successful repair was done when the posted found the harness chafed in the transmission/bellhousing area. I've checked on mine and my harness is in good shape in that area

I was originally going down the path that the harness was shorting. If that was the case I was just going to buy the 4 connectors for CAM, MAP, Crank and VSS sensors and build a harness for that complete circuit.

Unless I see the signals drop at the ECU, though, I believe troubleshooting is leading me away from that.

I did get a little traction on another forum and have some traces from the various brand CAM sensors that vary from what the original factory shows in terms of pulse width.

This weekend I'm going to compare traces on the 3 sensors I have and see how they compare. Only takes 5 minutes to swap them - including dropping the screw a dozen times!

Also going to gradually rotate the OPDA within it's slop range and see if the ECU is sampling at the edge of the pulse as currently calibrated, instead of the center. My money says the cam/crank relearn includes the ECU determining where mid-pulse occurs on both the cam and the crank.

All fun stuff...

I'll share the traces once I have them...

Still looking for CAM/Crank relationship - seems the trading site for people that request/receive those is on Facebook. I don't do Facebook. I'll have to get one of my offspring to get request that!
 
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I discovered the PCM firmware is coded to retard the engine at 4,000 rpm in park or neutral or at 90 mph on the road. I put my LJ on a dyno before and after my supercharger install, imagine my surprise when it retarded at 90 and it still had rpm overhead to go.

Mine is now sporadically retarding at 4,000 rpm on the road and what I suspect is the transmission 'comb' switch is signalling the PCM the transmission is in park or neutral.

I downloaded my WasteBook stuff a few months ago and deleted my account, not going to be a supporter of left wing social media.
 

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If you do decide to get another PCM, just get the one from wranglerfix. I had an issue where my engine would die after it ran for a bit. It would start running again after I reset the computer by disconnecting the battery. But as soon as it got past the inital "safe" run mode and started learning sensor data, it would die again. I was not too sure it would fix my problem as I had a manual and everything I read was that the automatics were the ones with the bum computer. But I bit the bullet and got one two years ago and I am so glad I did--engine has been running fine since. Passes CA smog with no issues. Not cheap but worth it.
 

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Discussion Starter · #18 ·
Quick update - more details to come.

Got a waveform from the forum on ScannerDanner - good site for those working with scopes, scanners, and other diagnostic tools.

As I had anticipated, it showed TDC on my camshaft lagging from the known good waveform. I twisted the OPDA counterclockwise a smidge, and on the next startup the P0344 code was gone. Have 2 long drives on it totalling about 50 miles and it's solid. The waveform shows TDC arriving on the correct Crankshaft pulse. The change was about 10 degrees.

It was 109 degrees when I wrapped up. Later..perhaps weeks later...I'm going to move it back a bit more until I find where it's too early and then set it just a bit leading center. I'm expecting the new OPDA gear, against the worn camshaft gear will cause it to drift late after a bit.

I'll step through the troubleshooting and post pictures, traces and conclusions when I have a bit more time...

Question? How are well on adding to old threads? There's several long ones existing with excellent data on this issue that I can add to, or I can put my data here?

Thoughts?
 

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I would fill out your thread as you see fit. If you think some of your input would flow with an existing thread, go for it. We appreciate your contributions.
 

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Discussion Starter · #20 ·
This will be a series of posts so anyone working thru their own issues can understand how this all works.

This picture shows an OPDA, with the alignment pin in place. The engine is rotated to TDC according to the crank pulley. Then the OPDA is installed and the orientation relative to the crankshaft is assured. ASSUMING the gear mesh is perfect and there is no slop.

NOTE: The Crankshaft Position Sensor does not read directly off of the Crankshaft, so the signal is only as good as the OPDA/Camshaft gear.
75844


I DO know TDC is defined by the Crankshaft. This is the position that the OPDA should be in at TDC.

The rotation is clockwise and the pattern is 1-3-1-2-3-2. As you can see, TDC is at the first knob in the "3" following the "1".

For future - the notches create the +5 volts and the "knobs" are zero.
 
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