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Cam position sensor problem - AGAIN

Discussion in 'Neon' started by AllanC, Sep 10, 2016.

  1. AllanC

    AllanC Well-Known Member

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    Vehicle is a 2003 Dodge Neon with 2.0 liter 4 cylinder engine, 4 speed automatic transaxle. Odometer reading is 290,001 miles. I have posted previously about problems / failures of the cam position sensor on this vehicle.

    P0340 camshaft position sensor

    The cam position sensor and 3 wire electrical connector at the sensor was replaced in January, 2016. That eliminated the cam sensor problem with code P0340. Now I am starting to randomly get code P0344, intermittent signal from cam position sensor. Since I replaced the wiring harness connector and soldered all splices and used 2 layers of insulation on each of the 3 soldered wires, I do not suspect a shorted nor open wire in the harness. I think the problem is the sensor. I have driven the vehicle 9000 miles since sensor replacement.

    The sensor was a BWD aftermarket item from O'Reilly auto. I went with this replacement versus an OEM sensor because of the lifetime free replacement. Looks like I will get to use that warranty. I would not have such a guarantee on an OEM Mopar parts. Nine thousand miles is way too short a life expectancy from this sensor in my o

    Over the life of this vehicle (13 years) I have replaced the cam sensor at least 4 times and in 2 of those instances used OEM Mopar sensors. Life expectancy was a little better with a Mopar part but still less than 100,000 miles. I wonder if the sensor design is poor and heat related failures are common regardless if OEM or aftermarket? By contrast the cam position sensor on my 2000 Grand Voyager with 3.3 liter V6 with 179,000 miles is original and has not failed. But it is a different design. The crankshaft position sensor on the Neon is original and has not failed nor set a crank sensor trouble code.
     
  2. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    I would look elsewhere for the root of the problem after replacing so many sensors. Check the harness and check the actual contact from the harness to the ECM. Could be a problem with the contacts for that signal wire at the ECM.
     
  3. ImperialCrown

    Level III Supporter

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    I agree that it likely isn't the sensor itself going bad. There is something else happening here. Review the 'Possible Causes' on p. 144 here:
    http://oskin.ru/pub/chrysler-dodge/...2004_PL_Neon/18623-pl-powertrain_sgmldiag.pdf
    Do you have or can you borrow a decent scan tool that can sit in the seat next to you for a few days, or at least until it acts up again? One that can show live Cam/Crank data and Cam/Crank sync would be useful.
    Has the Crankshaft position sensor been replaced?
    Has it had a timing belt replacement and are the timing marks verified to be spot-on?
    Was this car built on or before 9/25/02? If so, this TSB 18-026-03A may apply. P0340 is shown on p. 2:
    http://www.ertyu.org/steven_nikkel/neontsbs/2003/18-026-03.pdf
     
  4. AllanC

    AllanC Well-Known Member

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    Bob L: very good point. When I soldered the new electrical connector into the wiring harness, I removed all 4 connectors at the PCM so as to avoid any possible damage of heat or electricity traveling through the harness to the PCM. But I did not check the pin and receptacle in connector #2 which carries the cam sensor signal to the PCM. That will be easy enough to scrutinize.

    I know that I was extremely careful and diligent in performing the soldering task. I double insulated each solder joint so as to not have any short across the joints to an adjacent wire. Also the solder joints were staggered so as to not have each freshly soldered connection next to another soldered connection. I did not want this wire connector replacement to haunt me in the future.

    Build date according to door sticker is Dec 2002. Vehicle diagnostics has never displayed any of the trouble codes listed in the TSB other than code P0340.

    I have owned the car since Dec 2003. Vehicle had 22,000 miles at that point in time with a dealer owning it previously. I have never replaced the crankshaft sensor nor has any crankshaft sensor code ever been set in vehicle diagnostics.

    I personally replaced the timing belt at 100000, 150000, 250000 mile intervals. I never had a situation with my timing belt maintenance where the belt was 1 tooth off from correct timing. In Mar 2016 I finally diagnosed a coolant loss problem do to a failed head gasket. I farmed that job out to an independent repair shop. Odometer miles was 282,600 at that time. Timing belt, belt tensioner pulley and water pump were replaced along with head gasket. Six weeks prior to this I replaced the cam sensor and cam sensor electrical connector pig tail. I drove the car for about 1100 miles before the head gasket repair and no cam sensor diagnostic code appeared. I am confident that the timing marks are correct. Besides, if the crankshaft and camshaft timing were off by one tooth a diagnostic code P0016 would be set? I have never experienced that code on this vehicle.

    I have an Actron CP9180 scan tool. It does have some graphing capability but the screen is very small so it might not give sufficient detail.

    IC: I believe what you are indicating by scan tool is something like an expensive Autel or Snap - On Verus which allows multiple channels and allows graphing of several sensor wave forms simultaneously in detail? I have watched techs on YouTube use such tools to capture electrical wave forms from sensors. Would the idea of using such a tool be to identify which signal is failing? Is it possible that the cam sensor diagnostic code, P0344, is misleading and the real problem is with the crank sensor? I know many YouTube videos by techs point this out with Chrysler designed engine management software systems that a cam sensor diagnostic code can be caused by the crank sensor signal failure and vice versa.

    I will check connector #2 at the PCM, cavity 34 for the cam sensor receptacle mating to its pin at the PCM. Next door at cavity 35 is the connection for the crank sensor signal. I need to make sure no debris is present and causing an electrical signal to cross to a location that it should not cross. Will check and report back in a few days. As always, thanks for the tips.
     
  5. AllanC

    AllanC Well-Known Member

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    On Tuesday Sep 13 the check engine lamp illuminated again. Code P0344 has returned. On Sep 11 I had removed connector #2 at the PCM and cleaned the mating receptacle cavity #34 in the connector which is the circuit for the cam sensor signal. If there was a poor or intermittent connection at that point, this should resolve the issue. Vehicle was driven 200+ miles and code returned. I also inspected the wire harness for the cam sensor inside the wire loom. I did not see any issues with the wiring.

    Next step is to look at the crankshaft position sensor and its connector. The car has never experienced a crank sensor problem but I want to scrutinize it carefully. On Chrysler electronic engine management systems. it is possible that an issue with the crank sensor can set a cam sensor code. I want to try and eliminate that possibility.
     
  6. ImperialCrown

    Level III Supporter

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    If you read the 'Possible Causes' in the powertrain manual, you will see that an intermittent Crankshaft Position Sensor signal can set a Camshaft Position Sensor fault code. It does happen and I have replaced both sensors when in doubt with the waveform display. That is why I asked.
    A PCM is also on the Possible Causes list.
    It would be great to verify the problem with an advanced scan tool. I know that you are extremely skilled and methodical when it comes to diagnosis, but this sort of thing may need a higher-end tool to see what the PCM is or isn't seeing.
    The CKP (crank position) sensor is also listed in the Possible Causes for P0344.
     
  7. AllanC

    AllanC Well-Known Member

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    I C: Thanks for "stroking my ego" a bit. That will get me a few more miles down the road :)

    I have been watching YouTube channels produced by South Main Auto, Pine Hollow Diagnostics, Scanner Danner and I see how these guys use a Verus or Autel scan tool and plot multiple sensor signals and can identify when a signal drops out or goes crazy. That takes patience and an expensive scan tool and I am not quite ready to get that involved in electronic tools.

    For now I am going to do more circuit and connector checking on this problem. Then if the code P0344 still returns I am going to fire the "parts cannon" and get a replacement cam sensor. The last one purchased has a lifetime warranty so it will not cost me dollars to replace but just my time.

    I just wonder if the electronic hall effect circuitry that is inside the sensor has a problem with heat? The sensor has a broad surface (about 2.5 inches square) that mates to the side of the head. That gives it a lot of heat exposure and then many, many cold-hot-cold thermal cycles. But one would think a hall effect circuit would either work or not work. No intermittent condition unless there is an internal connection problem that is manifested during the heat up, cool down cycle. Oh well, this keeps me challenged in retirement! More to come.
     
  8. pt006

    pt006 Active Member

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    Allan; the PT Cruiser Links site has had many discussions about failures of aftermarket cam sensors. Also, there is a magnet behind the sensor that might have a crack in it, or be contaminated with gunk. I think the torque spec is 30 INCH-lbs. I had a p0340 code on a 2.4 L show up on an engine with only 80K. A new aftermarket sensor cured the problem for at least 50K more miles. Don't remember the brand.
     
  9. AllanC

    AllanC Well-Known Member

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    Thanks for the reference. I went to the site PT Cruiser links and reviewed some of the comments about code P0340 and P0344 which pertain to the cam position sensor diagnostics. With so many things to check it is easy to forget about the magnet and it being cracked and possibly causing a signal problem. The detective work continues.
     
  10. AllanC

    AllanC Well-Known Member

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    I have solved this issue. I have been tardy in continuing to report but a concurrent problem with an illuminating battery icon lamp as been a higher priority.

    On Sep 14 I finally decided to look at the 3 wire electrical connector at the cam sensor. I have not previously looked at this connector since the sensor itself was replaced in Jan, 2016. At the same time I also replaced and soldered into the wiring harness a new 3 wire receptacle connector. Since these parts were new in the recent past I felt that there was no need to inspect. They HAVE TO BE CLEAN. That is where I went astray.

    When I removed the connector I found oil on the internal terminals. The terminal receptacles should be clean and dry. There is an internal oil leak from the end of the camshaft and through the sensor onto the terminals. In retrospect this has occurred before on an OEM Mopar sensor and several other after market sensors I have installed on this vehicle. I was just not expecting this to happen again. I cleaned the oil from the terminals and sprayed cleaner into the mating pins on the sensor. Vehicle has been driven about 2 weeks in both highway and stop and go traffic and code P0344 has not returned. But the problem will occur again in the future and probably within the next 6 months.

    So the internal hall effect circuitry in the sensor did not fail. That is comforting. The problem seems to be a sensor design that tends to leak oil onto electrical contacts after a period of time. Thermal cycling from hot - cold - hot probably makes it difficult to maintain an effective, physical seal between hot oil and the circuit pins in the sensor.

    Take away from this is NOT to assume any state or condition. Sometimes what you think cannot or will not happen does happen.
     

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