Intrepid speed speed sensor problems

Discussion in 'General Motoring' started by Erehwon, Nov 17, 2007.

  1. Erehwon

    Erehwon Guest

    2000 Dodge Intrepid with 3.2 liter engine. On starting yesterday,
    speedometer stayed at 0 and transmission, after starting in first gear, went
    to second at a few mph and locked there. Engine light also came on. Based
    on searching this group it sounded like speed sensors. Local shop indicated
    computer showing codes P0700, Transmission circuit failure, and P0731, Ratio
    Error - Input doesn't match output. Based on that info they replaced both
    input and output speed sensors and reset the error codes. Got the
    speedometer working but still goes to second after a few seconds of driving
    and locks there. Unfortunately, no engine light and no error code (engine
    light does come on briefly when starting as usual). Sitting idle
    immediately after starting, I can go to "auto stick" mode and shift back and
    forth through first, second, and third but still jumps to 2nd after a few
    seconds of driving. Any ideas where to go next? Car not worth spending
    substantial $$$.
     
    Erehwon, Nov 17, 2007
    #1
  2. Erehwon

    Bob Shuman Guest

    Yes, it sounds like the transmission output speed sensor was bad. Did you
    disconnect the fuse to the transmission computer or optionally pull the
    battery for 5-10 minutes to do a hard reset?

    Bob
     
    Bob Shuman, Nov 18, 2007
    #2
  3. Erehwon

    Erehwon Guest

    I asked the shop the same question and they said it was unnecessary to
    disconnect the battery since the device they used to read the codes was also
    capable of resetting the computer. Possible or am I being given a line of
    .....? I'm fairly sure the battery was never disconnected since the time was
    still correct and all the radio stations I had entered were still there.
     
    Erehwon, Nov 18, 2007
    #3
  4. Erehwon

    Bob Shuman Guest

    This should be fine if the scan tool actually had that capability for that
    vehicle, but did they actually remember to perform the reset?

    Bob
     
    Bob Shuman, Nov 18, 2007
    #4
  5. Erehwon

    Erehwon Guest

    Thanks. Engine light finally came back on and shop found input speed sensor
    connection to transmission control module corroded. Repaired and back to
    normal. Perhaps that's what killed the speed sensor in the first place.
     
    Erehwon, Nov 19, 2007
    #5
  6. Erehwon

    Bob Shuman Guest

    This does not make sense to me since you indicated the speedometer stopped
    working when the transmission went into limp mode (2nd gear). This would
    indicate the output speed sensor (which measures the RPM of the drive shaft
    to the front wheels) was at fault and not the input sensor (which measures
    the engine RPM into the transmission).

    From your description (originally no speedometer, then had speedometer, but
    wouldn't shift), I'd suspect that they most likely damaged the input sensor
    connector when they replaced that sensor. If the facts you conveyed are
    accurate, then the only other alternative here is that the output sensor
    failed and then the connector failed too shortly thereafter and before the
    two sensors were replaced. This seems like a real stretch to me ... they
    almost certainly caused this poor connection when they removed/reconnected
    it.

    In any event, I'm glad to hear you have resolved the issue.

    Bob
     
    Bob Shuman, Nov 20, 2007
    #6
  7. Erehwon

    Mike Y Guest

    While I agree that actions of the shop probably caused the 'cascade' from
    one failure to two, I think a lot of times just the fact that ANYONE, no
    matter how capable, getting in there and disturbing things to look, test,
    and repair, can cause some secondary failures to come to the surface.
    I wouldn't be upset with the shop.

    Mike
     
    Mike Y, Nov 20, 2007
    #7
  8. Erehwon

    philthy Guest

    if they replaced both i hope they used factory parts
    if the pcm stores the code and the trans store the code and were not cleared in
    both modules then there is a good chance the issue will continue
     
    philthy, Nov 22, 2007
    #8
  9. Erehwon

    maxpower Guest

    Not true at all, Don't you know what a good trip is? If the check engine
    lite is on and you fix the problem, depending on what the fault code is for,
    it will be cleared on 2 or 3 good trips as long as the problem is fixed. A
    fault code stored WILL NOT make the problem continue (unless the problem is
    not fixed). The best way to determine if the problem is fixed is by letting
    the controller make the decision. Doing a battery disconnect or erasing the
    data on the PCM is not a good idea at all.

    Glenn
     
    maxpower, Nov 22, 2007
    #9
  10. Erehwon

    Bill Putney Guest

    Why not? If the code doesn't come back, then you're good to go. Plus
    on certain repair jobs, the computer needs to be kicked into a parameter
    relearn rather than running on the old settings based on defective
    operation.

    Bill Putney
    (To reply by e-mail, replace the last letter of the alphabet in my
    address with the letter 'x')
     
    Bill Putney, Nov 22, 2007
    #10
  11. Erehwon

    maxpower Guest

    If the transmission is in limp in mode and the speed sensor corrected the
    problem the PCM will see this. If your gonna clear the codes to see if the
    problem returns, why not leave the code there to see if the good trip clears
    it? If a sensor fixed a problem the lite will go out. Why clear out all the
    monitors and fuel adaptives? If you have a cylinder misfire and replace the
    plugs/ wires and then clear the misfire monitor you wont know if the
    problem is fixed until the monitor will run. If you replace a plug wire/plug
    and don't clear out the monitor the fault code will return when you drive it

    Glenn
     
    maxpower, Nov 22, 2007
    #11
  12. Erehwon

    philthy Guest

    i have seen it happen many times, you wouldn't think it would. but sometimes
    it does.
    i have even had to discharge capacitors in modules to get things back to
    correct
     
    philthy, Nov 24, 2007
    #12
Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.