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PCM wiring diagram?

Discussion in 'Explorer, Ranger - Computers, Chips, Tuning' started by Johnny Glenn, December 8, 2009.

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    1. Johnny Glenn

      Johnny Glenn Active Member

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      I've got an 02 Ex, 4.0L that I'm trying to find info on PCM / TPS connection. The TPS isn't signaling trans and it's new, so I'm thinking possibly PCM? Thanks.
       
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    3. High_Order1

      High_Order1 Active Member

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      Hey -

      sorry your having troubles.

      How do you know the sensor isn't talking to your transmission? (It really shouldn't be.)

      What codes are stored, and what do you see in live view or with a voltmeter? There are three wires if memory serves (search around here, the answer is in one of my threads), you are looking for 3-5vdc.

      Shawn
       
    4. Johnny Glenn

      Johnny Glenn Active Member

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      Thanks for the response - help has been sparse on the forum lately?! The TPS was faulty which caused the trans to shift terribly - as in 6k rpm or I had to let off gas for it to shift. I imagine many transmissions have been replaced because a faulty TPS?! For future reference -do you know where to find a PCM diagram?
       
    5. High_Order1

      High_Order1 Active Member

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      Are you wanting the pinouts for the entire PCM? Or a block diagram to explain what the PCM does?

      If your TPS was failing, did you notice any other issues that cleared? That is a critical part, and you should have gone into limp-home mode until the sensor was replaced.
       
    6. Johnny Glenn

      Johnny Glenn Active Member

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      I'm still trying to find entire pin-outs for PCM. On this repair, I was attempting to find pin-out for TPS to see if signal was present. It turned out it was a faulty TPS and I replaced with two aftermarket parts and they didn't work?! Once it was replaced by OEM everything was back to normal - It was amazing to see that a little sensor like the TPS would make it seem as if the transmission was shot!! I imagine many transmissions have been replaced because of that sensor?!
       
    7. High_Order1

      High_Order1 Active Member

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      jg-

      I apologize for not coming back in here sooner. Those pinouts are buried in the official service DVD. I HIGHLY recommend getting one, they used to be on the net until some people complained. I had a contact hook me up, but I bought one for my moms escape for about 20 bones on ebay.

      The problem is that those connectors are some of the most dense plugs and sockets I have ever seen outside of a tank or aerospace applications. You can't backprobe them because you'll destroy the water sealing, and a little water can make that thing haywire.

      You shouldn't use anything but an oscilloscope, a regular light can cause issues.

      I'm sorry I don't have time to dig through and get that for you, but next time I have to get in there, I'll pdf what you've asked.

      -Shawn


      PS - I'm still weirded out by the fact you had failing throttle position sensors. IF the PCM doesn't like what it sees several hundred times a second, it invokes FMEM, and can do everything from limit the throttle to completely shut the throttle off.

      All the TPS does from my old research is provide a closed feedback loop to the PCM. It doesn't look at RPM, it measures a delta in throttle plate movement from an assumed midpoint. In other words, when the PCM goes through crank up, it 'sees' the value from the TPS, and assumes that is butterfly closed. Any change of that value in one direction indicates butterfly moving. ANy in the opposite below the initial threshold tells the PCM it was wrong, and to recal.

      Your transmission is commanded to shift via a couple of things. Mainly what the PCM's adaptive shift schedule strategy says to, and partially via the line pressure sensors, turbine speeds, and percieved wheel speed.

      My problem is that I have huge tyres (I like the Brit spelling). And, the PCM can't understand that. So, I have a cumulative speed error that PISSES off the PCM, and I get grrrd shifts, and a lot of hunting in and out of OD.

      But, I don't know what I don't know, so your idea could have some merit... (toddles off to read some more...)

      Shawn
       
    8. High_Order1

      High_Order1 Active Member

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      oh - take a few minutes and peruse the transmission forum. there are a couple of common failure modes in the 5R55 trannys... see if yours matches...

      Shawn
       
    9. Johnny Glenn

      Johnny Glenn Active Member

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      Thanks Shawn for the info - I'll try and track down one of those DVD's - search "Explorer Service DVD"?

      As far as the repair, replacing TPS with OEM part solved the problem instantly. The vehicle went from 6k rpm shifting or shifting only when letting off pedal for a moment to.....normal!! Works for me!! Thanks again.
       
    10. High_Order1

      High_Order1 Active Member

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    11. jah81592

      jah81592 Well-Known Member

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      Try alldata they have exact pinouts.
       

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