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P0340 code woes

Discussion in 'Wrangler JK (2007-2017)' started by Brett_Alan, Jul 20, 2019.

  1. Jul 20, 2019 at 2:31 PM
    #1
    Brett_Alan

    Brett_Alan [OP] Member

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    My 2010 3.8 keeps throwing the cam sensor code P0340 with the traction control light with limp mode. I've cleaned connections on the harness for the cam, air, and coolant sensor. Wiring looks OK to me other than the tightness of it and exposure where the brittle plastic loom disintegrated.

    This all started a day after flushing the antifreeze and changing oil. But the first code thrown was P0116 coolant sensor. So replaced that and the thermostat. That code went away and the P0340 popped up with the traction control light. I can clear the code and start it, only to have it pop right back up. It doesn't start every time, as would be expected with the cam sensor erroring out. I haven't replaced that yet since I've seen so many guys just throwing part after part at it, to no avail. I probably will order a new one tomorrow, though.

    I've scoured the internet, found lots of people in my predicament, but no answers. I'm at a loss and was supposed to take it on vacay on the beach tomorrow for the week. Now we're taking the nissan sentra so you can imagine how I feel right about now. :(

    Thanks in advance, guys. I'm all out of skill.
     
  2. Jul 20, 2019 at 6:28 PM
    #2
    JKBob 25

    JKBob 25 Well-Known Member

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    Welcome to the forum dude @Brett_Alan .
    Sensor issues suck. I don't understand why people just start throwing parts, and hope for a fix. Replace the sensor.
    Anyway. Post up if your fix is the sensor. Would definitely help members in the future.
     
    Brett_Alan[OP] likes this.
  3. Jul 20, 2019 at 7:03 PM
    #3
    Brett_Alan

    Brett_Alan [OP] Member

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    Thank ya sir. All I can hope for is a miracle post from someone here while I'm at the beach without my jeep for four days.
     
    JKBob 25 likes this.
  4. Jul 20, 2019 at 7:15 PM
    #4
    JKBob 25

    JKBob 25 Well-Known Member

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    Dude.... @Brett_Alan . enjoy your time at the beach. I live at the Jesey Shore. I get it.
    Check back when you return to asphalt jungle....Hope there's a miracle post for ya.
     
    Brett_Alan[OP] likes this.
  5. Jul 25, 2019 at 4:40 PM
    #5
    Brett_Alan

    Brett_Alan [OP] Member

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    Well we made it back. Still no miracle posts here. I'll order the cam sensor tomorrow (genuine Mopar to be sure) and see how it goes. But the fact that I threw two codes associated with sensors on the same harness, I'm leaning towards a. Wiring rather than sensor problem. But chasing down that stuff with a multimeter has never been my strong suit (i.e. I suck at troubleshooting electronics).
     
    JKBob 25[QUOTED] likes this.
  6. Jul 25, 2019 at 6:32 PM
    #6
    JKBob 25

    JKBob 25 Well-Known Member

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    Same here dude. I absolutely suck troubleshooting electrical issues. But I am learning. And this forum is helping.

    Sorry there was no miracle post here. Some times. We, the forum, just don't have the answer and a fix. Hope it all,works out for ya. And it doesn't cost ya a buncha cash. But, post up your eventual fix. Could help some one in the future.
     
  7. Jul 25, 2019 at 7:33 PM
    #7
    Brett_Alan

    Brett_Alan [OP] Member

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    I cross posted in another forum and on a Jeep Facebook group. I'll definitely post up my eventual fix. I just hope it isn't a saga as I've found on other forum searches. I have to work tomorrow but will order a Mopar sensor from the stealership and do some more wire checking until it arrives. I did learn how to test the sensor so I'll probably pull it again and do that too, while I'm waiting for the new one.
     
    aggrex and JKBob 25[QUOTED] like this.
  8. Jul 25, 2019 at 7:53 PM
    #8
    JKBob 25

    JKBob 25 Well-Known Member

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    "Stealership"...:rofl:. I knew i liked you. Still not sure why. Lolllll. :thumbsup:
     
  9. Jul 26, 2019 at 6:28 AM
    #9
    Awrench

    Awrench Well-Known Member

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    p0340 is a CIRCUIT issue - the PCM is not seeing the CMP signal.

    And as suspected circuit issues are the most fun and exciting thing we do. SO trying to work this.
    You need a scanner,
    Check for all codes, WAG I think there are more codes.
    live data, graphing ability,
    DVOM and a wiring diagram.

    totally TMI but we want to get you the info if you want to tackle this
    Possible Causes
    (F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
    (F856) 5-VOLT SUPPLY CIRCUIT OPEN
    (F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
    (K44) CMP SIGNAL CIRCUIT SHORTED TO VOLTAGE
    (K44) CMP SIGNAL CIRCUIT OPEN
    (K44) CMP SIGNAL CIRCUIT SHORTED GROUND
    (K44) CMP SIGNAL CIRCUIT SHORTED TO THE (F856) 5-VOLT SUPPLY CIRCUIT
    (K900) SENSOR GROUND CIRCUIT OPEN
    CAMSHAFT POSITION SENSOR
    CRANKSHAFT POSITION SENSOR
    POWERTRAIN CONTROL MODULE (PCM)

    3.8L  CMP.jpg
     
    JKBob 25 likes this.
  10. Jul 26, 2019 at 6:08 PM
    #10
    Brett_Alan

    Brett_Alan [OP] Member

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    Thank you for this. If this newly installed CPS doesn't keep away the dreaded codes, I'm going to have to find a garage or someone somewhere with a nice scanner. I've only got a basic one.
    So far, the code is gone but I haven't ran the Jeep for over an hour yet, which is when the moment of truth seems to be. The guys who've had this same problem usually enjoy a well running jeep for a day or so until the code and limp mode suddenly comes back and they're on the side of the road. That's when they end up focusing on the fun and exciting wiring, which I guess I'll do if this new CPS doesn't fix it.
     
    JKBob 25 likes this.
  11. Jul 26, 2019 at 6:14 PM
    #11
    Brett_Alan

    Brett_Alan [OP] Member

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    We'll I got the new 100 friggen dollar CPS installed. I'm hoping this is the fix but not holding my breath. But check out the oily moisture on the plug of the old CPS. No way should it look like that. I'm hoping that indicates that it was just a randomly timed failure of the CPS, rather than a wiring issue related to my accidentally yanking a wire loose somehow. I did check out the wiring and sprayed contact cleaner on the connection points.

    20190726_201343.jpg
     
    JKBob 25[QUOTED] likes this.
  12. Jul 26, 2019 at 6:23 PM
    #12
    JKBob 25

    JKBob 25 Well-Known Member

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    I gotta learn how to read these things......:( :annoyed:
     
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  13. Jul 27, 2019 at 5:03 AM
    #13
    Awrench

    Awrench Well-Known Member

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    :fingerscrossed: hope for the best.

    :evil: Getting anal -
    a cam sensor is called a CMP.
    the Crank sensor is called CKP and jeep lovers use CPS.
    I believe in photo you are holding a CMP, and confusing as the subject, I needed to be sure.

    FYI: A CKP is a suspect second from bottom on POSSIBLE CAUSES. details another time.
     
  14. Jul 27, 2019 at 5:11 AM
    #14
    Awrench

    Awrench Well-Known Member

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    JKBOB 25 - If you can read a map you can read those diagrams..... the wires would be roads.

    just ask even someone from the shore can pick it up,
     
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  15. Jul 27, 2019 at 8:02 PM
    #15
    Brett_Alan

    Brett_Alan [OP] Member

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    Don't know ‍♂️ the code read cam position sensor and the part is called Cam Position Sensor.

    And so far so good. Took it on an hr long drive then a shorter one with no codes. I'm still keeping my fingers crossed as most of the guys start getting the code again a couple hundred miles after replacing it.
     

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