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  • TCU Communication

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    Unnecessary thread. Please delete.
    Last edited by ChrisAudi80; 24th February 2018, 05:39.
    '96 UrS6 auto PRJ chipped E85
    '95 80Q AEB VEMS E85

  • #2
    Originally posted by ChrisAudi80 View Post
    I'm curious about the communication between ECU and TCU on S6 autos.

    The shift point signal from TCU to ECU pin 51, does it vary between 0-5v depending on load or is an on/off signal?
    The SSP says a constant signal will cause a short to ground and the signal will be ignored - I would guess it's a ground signal during the shift operation.
    At the moment I drive a S6 V8 automatic, I can change my datalogger (Innovate 4 Channel) and log the automatic transmission signals :-)

    The TCU also needs a load signal in the form of fuel consumption based on IPW from pin 31.
    I saw in another thread mentioned that a variable 0-5v output can be used instead for fuel consumption. Can this signal also be used by the TCU for load?
    I think next week I will remove my ECU back to my desktop and then I will solder the wires to the TCM communication.
    I can log several driving situations and send you the logfile.

    At the moment I'm playing with the idea to check if it's possible to give the V8 motronic 4 ignition outputs to run wasted spark :-)
    But for this I must understand much more of the code... unfortunatly ;-)

    I can say that the V8 manual ECM can be made to a V8 automatic incl IMMO. There is no hardware difference, everything works.
    You can also drive manual bin file but shift operation is very hard, so a signal for the TCM is missing.
    I will also try this to understand better.

    Can somebody tell something about the DTC classes?


    Comment


    • #3
      Originally posted by Acki View Post

      The SSP says a constant signal will cause a short to ground and the signal will be ignored - I would guess it's a ground signal during the shift operation.
      At the moment I drive a S6 V8 automatic, I can change my datalogger (Innovate 4 Channel) and log the automatic transmission signals :-)



      I think next week I will remove my ECU back to my desktop and then I will solder the wires to the TCM communication.
      I can log several driving situations and send you the logfile.

      At the moment I'm playing with the idea to check if it's possible to give the V8 motronic 4 ignition outputs to run wasted spark :-)
      But for this I must understand much more of the code... unfortunatly ;-)

      I can say that the V8 manual ECM can be made to a V8 automatic incl IMMO. There is no hardware difference, everything works.
      You can also drive manual bin file but shift operation is very hard, so a signal for the TCM is missing.
      I will also try this to understand better.

      Can somebody tell something about the DTC classes?

      I see. Just a switch? How does the TCU tell the ECU the number of degrees to retard timing? Or does the 551D ECU have a lookup table for that? My S6 is not running right now due to faulty injector. Stuck open.
      Otherwise I would stick a DMM on pin 51 and measure while shifting. I really want to know the signal types and parameters for the ECU- TCU communication. There are only 5.
      pin 31: fuel consumption signal for load, shared with board comp. Dmitri said in separate thread can be 0-5v pwm out.
      pin 40: tacho signal.
      pin 42: gear selector switch. Probably a lockout so it does not start except in P and N.
      pin 51: shift point signal. On/off, variable 0 to 5v?
      pin 54: TPS signal
      '96 UrS6 auto PRJ chipped E85
      '95 80Q AEB VEMS E85

      Comment


      • #4
        I would expect the ECM retards timing until the TCM says it’s enough via the difference speed of the converter speed (measuring block at the TCM show you this speed).
        Pin 54 is a PWM Signal according to the SSP, generated by the ECM.

        I want to understand the shift operation anyways for more „poops and bangs“ during shifting. Hehe.

        @vwnut: 3.6 V8 has the same system like 4.2 V8. Dual distributor, two coils. Nothing more. I have ALL V8 bins collected. Audi V8 till S6+ and some A8/S8.

        Comment


        • #5
          Originally posted by Acki View Post
          I would expect the ECM retards timing until the TCM says it’s enough via the difference speed of the converter speed (measuring block at the TCM show you this speed).
          Pin 54 is a PWM Signal according to the SSP, generated by the ECM.

          I want to understand the shift operation anyways for more „poops and bangs“ during shifting. Hehe..
          Yes, this is what I want to know.

          If it is a variable voltage, it will tell ECU to retard timing by x degrees depending on voltage signal. Other way I can think of is by table switching or something.

          Clear on PWM from pin 54.

          I am looking at the current flow diagram for the TCU and comparing it to AAN ECU pinout. It does not match. The current flow diagram is for MY97 made 06.96. Did it change after 95?

          ECU pinout says pin 51 goes to TCU pin 32. Current diagram TCU says pin 51 goes to pin 20.
          ECU pinout says pin 54 goes to TCU pin 47. Current diagram TCU says pin 54 goes to pin 7.

          What else does your SSP say for shift point signal? If it grounds, would that mean on/off function?
          '96 UrS6 auto PRJ chipped E85
          '95 80Q AEB VEMS E85

          Comment


          • #6
            Yes idle is different for manual and auto.
            But knowing is better than guessing.

            For the TCM, for the V8 there was a difference at MY95. With the DSP function in the TCM.
            New and old shift strategy etc pp.
            But for the 20V I don’t know. I only can check my V8 auto. I could image a lot of possibilities for the shift signal but didn’t helps to understand it better.
            I can try to check for old SAE papers. Sometimes some helpful explanations are found there.

            Comment


            • #7
              I am not guessing anything, every statement I have made is fact. There is absolutely no difference in TCU communication between any of the ECU revisions. The same protocol/logic is used and all ECU's are equivalent hardware wise.

              With TCM yes, there was a TCM change at MY95. Does not affect the ECU though.
              http://tuner.ee - http://www.facebook.com/tuner.ee

              Comment


              • #8
                Originally posted by prj View Post
                I am not guessing anything, every statement I have made is fact.
                Sorry, wrong context - was about my ideas how the shift signal will be used in the ECM.
                Finding and checking the routine and then I have to understand what happens.



                Comment


                • #9
                  ////
                  Last edited by ChrisAudi80; 24th February 2018, 05:40.
                  '96 UrS6 auto PRJ chipped E85
                  '95 80Q AEB VEMS E85

                  Comment


                  • #10
                    Originally posted by ChrisAudi80 View Post

                    acki any update on this? I think I will buy this http://www.piccircuit.com/shop/pic-d...-daqduino.html
                    to log the signals in question. Do you know the frequency of the pwm out for fuel consumption? Is it constant or variable?
                    I will modify my ECM in the next days, is it ok for you?

                    Comment


                    • #11
                      ///
                      Last edited by ChrisAudi80; 24th February 2018, 05:40.
                      '96 UrS6 auto PRJ chipped E85
                      '95 80Q AEB VEMS E85

                      Comment


                      • #12
                        Today I changed my setting of my SSI-4, I struggle a little bit with the 5V signal it measures. I would think it's switchedground as usual but I have set all channels the same (CH+ is signal, CH- is ground).

                        I logged this PINs:
                        Pin 40 - engine speed (black line)
                        Pin 42 - gear selector switch (red line)
                        Pin 51 - shifting indicator (green line)
                        Pin 54 - throttle position (blue line)

                        Gear selector switch is 0 when P or N is selected, else it's "high".

                        Shift indicator is high when not shifting, and goind low when shifting.
                        -> Makes sense failure check is when always low then ignore this signal.
                        Throttle position sensor signal 1 - 4.5V; sure 0V would be stupid for fault detection.

                        Normal driving:
                        TCM.JPG
                        Fast accel, 1st and then 2nd gear. Engine speed measured to high somehow, I guess the Innovate stuff is too laggy for the measurements.
                        tcm2.JPG
                        Next step would to test the ECM at the table to check which table will be triggered when shifting.
                        I think I have to write a simple blink code to check how the input/output are used to find the used table/routine.

                        Comment


                        • #13
                          ////
                          Last edited by ChrisAudi80; 24th February 2018, 05:40.
                          '96 UrS6 auto PRJ chipped E85
                          '95 80Q AEB VEMS E85

                          Comment


                          • #14
                            I would expect a RPM Load Map. I will compare manual and automatic files for the V8.

                            DC and PWM isn’t it the same at the end?

                            Comment


                            • #15
                              ///
                              Last edited by ChrisAudi80; 24th February 2018, 05:40.
                              '96 UrS6 auto PRJ chipped E85
                              '95 80Q AEB VEMS E85

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