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Auto transmission problem

Discussion in 'PT Cruiser' started by Scotland1969, Oct 29, 2017.

  1. Scotland1969

    Scotland1969 New Member

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    Hi
    My 2007 cruiser is stuck in 2nd gear. I've read the codes and got p0935 which is a reference to line pressure circuit. Whereabouts can I find the wiring for this sensor and indeed the sensor itself?
    Many thanks
     
  2. ImperialCrown

    Level III Supporter

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    Welcome to Allpar. I find older PT information online for free, but you may need to purchase detailed service information for yours. The same 41TE VLP system and circuitry would be used in other models that use this transaxle, although the wire colors may vary.
    Line pressure 'high' may be an open ground? It is set when the signal voltage (Yl/Br wire) is 4.75 volts or higher. Normally the voltage should be below this. The LPS ground is a DB/LB wire returning to the PCM for its ground. I hope this gives you something to start with.

    Possible Causes
    LINE PRESSURE SENSOR SIGNAL CIRCUIT OPEN
    SENSOR GROUND CIRCUIT OPEN
    LINE PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE
    LINE PRESSURE SENSOR
    POWERTRAIN CONTROL MODULE (PCM)
     
  3. Scotland1969

    Scotland1969 New Member

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    Thanks. Great info. I'll get to work at the weekend. Where will I find the sensor itself? Do I have to drop the valve body?
     
  4. ImperialCrown

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  5. Scotland1969

    Scotland1969 New Member

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    Do you mean by checking the wiring first? Where does the wiring exit the gearbox?
     
  6. ImperialCrown

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    Look for a 6-terminal connector that exits the case with those 2 wire colors in the harness.
    Yes, don't blame the component right away until you can verify voltage and ground. It may not be the sensor itself at fault.
     
  7. Scotland1969

    Scotland1969 New Member

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    Thank you again, I'll take a look at the weekend.
     
  8. pt006

    pt006 Active Member

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    I couldn't find a listing for the p0935 code. So I'm assuming it is trans line pressure. The 3 pressure sensors are located inside the 'solenoid pack' , which is located externally on the front center of the trans. The trans pack is not repairable. There is an 8 prong connector that plugs into the 'pack'. It is a vertical plug. This connector can be inspected and cleaned. The 'pack' is grounded thru the 3 vertical hex head screws, so check that they are tight.

    There are at least 3 ground points, two on the left inner fender and one on the right inner fender [which is very difficult to see]. All are small hex head screws. Disconnect the neg battery post before cleaning and greasing the ground terminal ends.

    There is another connector hanging from the harness to the right of the 'pack'. Check and clean.

    If you decide to change the 'solenoid pack' : remove the air cleaner assy, the battery and tray, maybe the left speed sensor which is above the pack, and maybe the trans oil cooler lines [mark them]. And then clean the area around the pack very well, so that NO dirt or sand can get into the hydraulic system.

    Good luck
     
  9. ImperialCrown

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    Be careful here. Pressure switches inside the solenoid pack are not the same as pressure sensors for the variable line pressure (VLP) system.
    The pressure SWITCH in the sol pack will close to confirm to the TCM that the shift solenoid opened the passage of fluid to the clutch in order to engage it.
    The line pressure SENSOR tells the TCM what the line pressure is, so it can be adjusted by a solenoid 'dump' valve depending on conditions. By lowering the line pressure when full line pressure isn't necessary, it saves fuel, lowers heat generaton and probably increases pump life.
    (Click on the link in post # 4 to see the VLP sensor and solenoid placement on the VLP valve body).
     
  10. pt006

    pt006 Active Member

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    My 2006 manual lists only 40TE and 41TE trannys. It also doesn't show a p0935 code. So I did a little snooping and read that the TES trans was first installed in the 2007 Sebrings. And was installed in other models in later years. It was never installed in PT Cruisers. Neither was the V-V-T engine, nor the 6 speed auto. Chrysler just left the PT's on the vine waiting for them to die.
     
  11. ImperialCrown

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    It is true that the PT kept the (by then) old 2.4L and 41TE drivetrain until the end. This base powertrain had served us well since 1995.
    By the time of the World Gas Engines and 62TE (even the CVT) in 2007, the PT was antiquated. It was time to move on to updated technologies and architectures.
    Since the OP and the 2007 service manual have both the P0935 code listed and a servicing section on the Line Pressure Sensor, I have to assume that the 2007 PT had the updated 41TE VLP refinement as well.
    The Chrysler 41TE automatic transmission (transaxle) (at https://www.allpar.com/mopar/transmissions/41TE.html )
     
  12. Scotland1969

    Scotland1969 New Member

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    Hi again,
    it would seem that the gearbox has been changed for an earlier one at some point that does not have the connector for the VLP. The wiring harness has the plug though. Is it possible to disable this in the TCM?
    The joys of buying at auction!!
     
  13. ImperialCrown

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    Lovely. The PCM and TCM are a single unit on these and VLP configuration can't be changed if the software tells the processor that it has the VLP feature.
    Changing it to an older controller unit without VLP could violate federal emission certification laws. I also don't know if the connector pinout would have changed other than not using the VLP wiring terminals.
    I would investigate trying to find the correct 41TE transaxle w/VLP if you are planning on keeping the car. It may just be worth getting this the way it is supposed to be.
     
  14. Scotland1969

    Scotland1969 New Member

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    I thought that might be the response! I'm in the UK and we have no such laws (I think!) I wasn't planning on keeping the car. Is it possible to have the software reprogrammed or to connect the ground from the connector to ground on the chassis to fool the PCM into thinking all is OK?
     
  15. ImperialCrown

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    Once the controller is assigned an application, it remains permanent and can't be changed. It may always be looking for the VLP hardware that isn't there.
    Unfortunately, the factory software updates only address improvements/enhancements to the existing program. You can't change the actual program.
    It must see variation in the pressure signal when prompted as a system self-test. Grounding it would likely just change the fault from an 'open' to a 'short'. I have not been able to fool a controller lately. Best of luck to you.
     
  16. Scotland1969

    Scotland1969 New Member

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    If I were to change the PCM would I need to have the key coded or is it possible to change the VIN in the ECU?
     
  17. ImperialCrown

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    A new PCM can have the VIN entered or learned from other modules. I am not sure that a used PCM VIN can be changed once it is learned, or it would need the Chrysler dealer agency tool to do so. This would help prevent theft.
    If a 'remanufactured or rebuilt' PCM can be found, the vendor may be able to send one with the correct VIN and key PIN code entered.
    We don't have the Immobiliser security system in the U.S., only the SKIM or SKREEM key communication with the Wireless Control Module (WCM), so I don't know much about how export vehicle security systems work. I found this discussion here:
    Key SKIM Immobiliser Starting Issue - Where to start - PT Cruiser Forum (at http://www.ptcruiserlinks.com/forum/tech-performance-forum/50257-key-skim-immobiliser-starting-issue-where-start.html )
     
  18. pt006

    pt006 Active Member

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    Scotland; I've got some more confusing information for you. My late 1980's truck [fuel injected - computer - 727 Auto] pops the code for a problem with the lock-up converter. So I looked underneath and discovered that the wiring harness plug to the back of the tranny was disconnected. Aaaaaah, easy fix, just plug it in. The problem is that there is nothing to plug it into. So after much wasted time, I discovered that the truck never came with a lock-up converter for the 727.

    Plan B: Another way to tell which trans is in you car, or which one it came with, is to check the build plate located on the very right side of the firewall. The bottom line on one of the corners should read DGL for a 40/41TE or DFF for a 41TES [the VLP trans]. So I went out to check my 2006. I expected to read DGL, but it read DGB [a truck transmission]. Confused yet? I am.

    I read that in 2007 they used both transaxles, and also read that they never used the VLP trans in any year PT Cruiser. So, unless you have the 3rd plug* on the trans [the one just to the left of the transmission range sensor plug], you have the 40/41TE trans.
    * one plug for the TRS, one plug for the solenoid valves, and one plug for the VLP sensor.

    I believe this to be true, but the info I found is a little vague.
     
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  19. ImperialCrown

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    I agree. A DFF sales code on the build sheet or body plate would confirm that this PT came with the VLP transaxle.
     
  20. Scotland1969

    Scotland1969 New Member

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    This is getting very confusing! By the firewall you mean the bulkhead, under the front windscreen?
     

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