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00 Grand Prix GTP lost D, 2, and 3

michaelstarr84michaelstarr84 Posts: 18
edited April 2015 in Pontiac
My GTP will not shidt into D, 3, or 2. I do have R and 1. While driving, in can manually upshift at the proper speeds all the way into D and drive with no problem. But when i stopped, i lost all forward gears and had to be towed. I then changed the 2 shift solenoids, the TCC, the PCS, and the main pressure switch ssolenoids. Same. Only 1 and R so i road tested it and got the same result. I then removed and rebuilt my transmission with a level 2 master kit, replaced the torque converter, and replaced the BROKEN forward band. I was so pleased with the find and the repair. Its all back in. Same thing. 1 and R only. Im baffled. Anybody? Anything?

Comments

  • thecardoc3thecardoc3 Posts: 4,994
    Start back at the beginning. What codes are setting in the PCM ? Do you have a scan tool that will show you data? If so what gear is being commanded? Does the range selector switch (also called the manual valve switch) show that you to have selected drive? Do you have bi-directional controls and will the transmission shift when commanded to with the scan tool?

    Do you have battery voltage to the PCM on pins 4 light green and 44 yellow /black of C1 and pin 78 brown of C2 with the key on, engine off ? If so, and you manually ground pin 4 light green at connector #1 does the transmission then shift to second gear?
  • I do have a scanner but its nothing fancy. I'm reading 0 codes. 
  • Got 2 pending codes after rebuild but that was due to the disconnection of the powertrain wiring harness. Everything went together well. I'm clueless at this point. I'm an accomplished do-it-yourselfer and have rebuilt transmissions before but I'm stumped here. I can check the pins with a volt meter and repost the results.
  • thecardoc3thecardoc3 Posts: 4,994
    You can check the pins for voltage and if you have it, you could then switch to amperage measurement and checking those same pins should produce an audible click from the solenoids in the transmission
  • michaelstarr84michaelstarr84 Posts: 18
    edited April 2015
    I will check and repost tomorrow or the next day at the latest. My volt meter is also very basic but I have a friend loaning me his tomorrow. 
  • Also, is it safe to drive the car around town just shifting through the low gears manually and just avoiding the D range until I isolate the issue?
  • thecardoc3thecardoc3 Posts: 4,994
    Really can't answer that. If it isn't right, then it isn't right.
  • Have located pins and will check after work. Will post results this evening
  • Sorry for delays
  • Unless I am improperly testing, there is no voltage on any of the 3 pins you wanted me to test. DTC P1860 has popped up also.
  • michaelstarr84michaelstarr84 Posts: 18
    edited April 2015
    P0717 is pending as well
  • P1860 is set and is also listed again as pending
  • thecardoc3thecardoc3 Posts: 4,994
    edited April 2015
    Check the TCC fuse in the under-hood fuse block on the right strut tower. If it is good and it has power to it then check for power to the transmission connector, pin E pink wire. If you have power there, and you don't have power coming back out of the transmission on those three wires to the PCM, then the problem is between the harness connector and the solenoids inside the transmission. That pink wire is the power supply for all three of them.

    P0717 is the input speed sensor circuit, and P1860 is the TCC pulse width modulated solenoid circuit. If you don't have power to the PCM on pins 4 and 44 of C1 it really should be setting P0753 and P0758 as well, you might want to double check to make sure that you were making a good connection when you tested those two pins.

    Carefully inspect the transmission wiring harness connector, and the transaxle connector to make sure that all of the pins are properly in place and not damaged.
  • michaelstarr84michaelstarr84 Posts: 18
    edited April 2015
    Traced my power. Fixed a loose connection and I have my forward gears back! :) after cycling the gears, to route the trans fluid, and topping off my fluid, I took my first road test. All D ranges engage and propel the vehicle forward but there seems to be a major lack of initial power and engagement for take offs. Once going it catches up well but the 1-2 shift missed and I get high rpms until speed reduces enough for 1 to reengage. Is this a quick learn issue or is there something else to add to my list? Seems like it may also be skipping 1 entirely and trying to take off in 2nd. Thanks a million for all of your time and consideration. You have helped me a helluva lot!!!
  • Update: second road tested resulted the same but set a DTC. P0742- TCC system stuck on
  • thecardoc3thecardoc3 Posts: 4,994
    Fun isn't it? We try to teach techs when faced with this type of a situation to close their eye's clear their mind and forget everything that they know about the car and start again from the beginning with the diagnostics. Some people say to go back over your work and see what you did wrong and that isn't correct because it assumes that you did do something wrong when there really isn't any proof of that at this point. If you take their advice and start out with an assumption like that you risk wasting tons of time whether it is something you did wrong or not.

    So from the beginning with this code as if nothing else has ever been done.
    P0724 TCC system stuck on.

    We instruct the techs to research what the code means and how the PCM runs the test. There is a switch inside the transmission that grounds a 5v signal from the PCM when the TCC is turned on. Fluid pressure opens the switch when the TCC is turned off.

    At this point compare that description to what it feels like when you are driving the car, is the TCC applied and the torque convertor not able to give you multiplication or is it not applied and working normally?
    With a scan tool a tech would be monitoring the TCC slip speed and using bi-directional controls to help interpret what the system is doing.

    The TCC apply switch is the yellow wire at the PCM connecter pin 63 of C2. Pin U of the transmission connector. A tech might find themselves having to confirm if the PCM is reporting the true state of the circuit and have to manually prove when it is grounded or not.

    Here is GM's explanation of the circuit. "The TCC release switch is a normally-closed switch. When the TCC is released, TCC release fluid pressure opens the TCC release switch which opens the TCC release pressure circuit. When the voltage on the circuit is high (switch open), the PCM recognizes that the TCC is no longer engaged.

    If the PCM detects that the TCC release switch is closed when the TCC is commanded OFF, then DTC P0742 sets"
  • michaelstarr84michaelstarr84 Posts: 18
    edited April 2015
    Yes, I haven't had the spark of life, that I get working on my car, in a long time :) I'm loving it! When driving, the shift to second doesn't happen. Instead it acts like it shifts to neutral and revs with no engagement. This sets DTC P0742. OEM manual suggests inadequate cleaning of valve body or pressure switch or a faulty valve piston. Am prepared to open side pan again due to lack of trans scanner and bidirectional controls. I replaced all of the solenoids during the rebuild too. Well the 5 main ones anyway. So it's quite possible that some gunk got missed. How I manually prove a ground?
  • michaelstarr84michaelstarr84 Posts: 18
    edited April 2015
    Also, was wondering as to the odds of some lubeguard or sea foam solving this problem for me. Will also start with the amperage test you suggested since I performed it improperly and never reran the test. I will post those findings tomorrow.
  • thecardoc3thecardoc3 Posts: 4,994
    Nah, a mechanic in a can isn't going to help. Can you picture a tech getting paid .3 hours to diagnose your transmission issues the first time and a little under 7 hours for the R&R and rebuild if it was under warranty?. Now picture them going to work and being paid nothing for any additional diagnostics and repair re-checks like you are wrestling with now.
  • michaelstarr84michaelstarr84 Posts: 18
    edited April 2015
    Makes complete sense. Running diagnostics now. And am also geared up to go back into trans today if necessary. I'll update as I progress.

    Update: amperage test produces audible             solenoid clicks at pins 4 and 44 of C1 and also pin 78 of C2. Getting zero results from pin 63 of C2
  • Still zero results :( side pan is off but everything looks sound. TFP and TCC are brand new so once again I'm stumped ;(
  • Got it! Traced power for pin 63 of C2 with engine running. Testing PCM (63 of C2) and got voltage. PCM is not shorted to ground interally. PCM is good. Tested pin U of trans cconnector. No voltage. TCC power wire is shorted to ground within the harness. Spliced new wire, soldered, shrink-wrapped, and taped to harness for neatness. Retested pin U of trans connector with the engine running and got voltage. One problem solved but my TCC is still stuck. Only thing left that is elecrical in that circuit is the AT internal wiring harness so I rush ordered one and just finished my repair. TCC system is no longer stuck on. I corrected 2 shorts to ground by manually proving a ground at key points along the circuit. Thus isolating the faulty part(s) of the circuit. Thank you for everything, including your silence during the last of this. I have learned a great deal in all of this. 
  • thecardoc3thecardoc3 Posts: 4,994
    edited April 2015
    Great. Through the years there has been constant pressure to try and make auto repair look like a for symptom "X" replace part "Y" job that is so simple anyone can do it. Even worse are the ones who believe that you just hook it up to a machine and it tells you what is wrong. You just got to experience what the job is really like. Techs have to take the details you observed, and using code description and testing criteria, schematics, critical thinking skills and all of the right tools efficiently figure out a way to work to a solution. All I did was have you make the checks as a tech would have to do as each issue is investigated.

    The greatest irony in all of this is rebuilding the transmission, that's easy. If you were working as a tech you would not have been paid for any time that was invested beyond what the rebuild paid and every possible insult, or slap in the face that someone could have tossed your way would have been used to belittle you for not solving the electronics issue in a matter of minutes. Electronics diagnostics like this are quite often anything but easy. That's even more so when some of it requires disassembling the transmission in the car especially if there is still doubt as to whether the failure is inside or external of the transmission. There are ways to prove where the circuit failure is most of the time but they can be labor intensive and with all of the pressure that is getting placed on the tech at that time they literally get trained to simply avoid this work. That's something that the consumer is starting to recognize the result of thirty plus years of mismanagement in the trade. They don't know what has caused it, they just know that they can't find the techs that they need easily.

    One thing that is still questionable is your statement that the yellow wire is grounded inside the harness. If it really is then it is not likely to be the only affected circuit. The bypass is OK to a certain degree and would be more advisable when you have an open wire, but not a grounded one. Time will tell but you might need to remove, disassemble and repair the harness.
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