Results 1 to 8 of 8

Thread: 411 pcm on tuned port with 2002 express van tune PROBLEM WITH SPEED OUT

  1. #1
    Potential Tuner
    Join Date
    Aug 2020
    Posts
    6

    411 pcm on tuned port with 2002 express van tune PROBLEM WITH SPEED OUT

    Hi all I just completed a swap of a 1999 vortec5.7 with distributor and a tuned port system with sequential fuel injection it runs great and no codes. I went to connect an electronic speedo to pin#50 and I get instant reading of 160mph and a voltage reading on the speed out just when I turn on the ignition I have done a pinout on every pin and I cant figure out what is causing a voltage reading on pin 50 with no speed the voltage is not battery voltage it is around 10 volts HELP thanks Le Johnson

  2. #2
    Advanced Tuner
    Join Date
    Oct 2013
    Posts
    550
    You are referring to pin 50 of the RED (C2) PCM connector, correct ?

  3. #3
    Potential Tuner
    Join Date
    Aug 2020
    Posts
    6
    Hi yes pin 50 red has voltage without moving

  4. #4
    Advanced Tuner
    Join Date
    Oct 2013
    Posts
    550
    There should be 9 volts from that pin (or on that wire) when stationary. When moving, this output will be pulsed at a rate of 4000 pulses per mile.

    The attached PDF is the diagnostic flow chart, for a non-functioning speedometer.
    Attached Files Attached Files

  5. #5
    Potential Tuner
    Join Date
    Aug 2020
    Posts
    6
    HI thanks for the input I get 12.6 volts on vss wire stopped and battery voltage is 14.1 volts Any suggestions thanks

  6. #6
    Advanced Tuner
    Join Date
    Oct 2013
    Posts
    550
    Quote Originally Posted by leess396 View Post
    HI thanks for the input I get 12.6 volts on vss wire stopped and battery voltage is 14.1 volts Any suggestions thanks

    Did you read the diagnostic flowchart that I posted ?

    Step 1:
    • disconnect the PCM Speedometer output wire from the electric speedometer
    • measure the voltage on this wire
    • if the voltage is now around 9 volts, then either the electric speedometer is defective, or the connections are incorrect
    • if the voltage remains around 12 volts, continue to Step 2


    Step 2:
    • disconnect the PCM C2 (Red) connector from the PCM
    • measure the voltage directly at pin 50 from the PCM
    • if the voltage is now around 9 volts, then there is a short to voltage somewhere along the Speedometer output wire itself
    • if the voltage remains around 12 volts, then either the PCM is defective, or the PCM has been incorrectly programmed

  7. #7
    Potential Tuner
    Join Date
    Aug 2020
    Posts
    6
    Hi thanks i didnt get the flow chart. I will check as per your last Thanks

  8. #8
    Potential Tuner
    Join Date
    Aug 2020
    Posts
    6
    Test completed. the voltage at wire#50 with ignition on not running 10.8 --- voltage at pin #50 on pcm with red disconnected is 8.91. I cut wire #50 near pcm to check for possible short and voltage remains same from pcm.