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Getting PO122 code - replaced throttle body assembly 3 months ago, so don't believe it is that. Saw something that accelerator pedal could be part of problem, and was able to capture this graph using VCDS while slowly depressing and releasing pedal. This is for Accelerator Pedal Position D and E. My understanding is that one is supposed to be twice the value of the other for fault checking purposes. As you can see there are drops. We replaced the accelerator pedal assembly, and are still seeing the same results.

  1. Can the drops be considered normal? and 2) if the pedal is not the problem, any other ideas?VCDS graph pedal D & E
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  • EFI systems can either easy or difficult to diagnose. Your P0122 may be a difficult one. A you may or may not know, most sensors operate on 5vdc. The ecm outputs 5vdc to every sensor needing it and if the distributed 5 volts is compromised anywhere from a short in wiring, there can be one or several false errors from intermittent supply voltage. The same for grounds. You may need to troubleshoot for steady 5vdc or if it's intermittent or an intermittent ground connection. Wired grounds are everywhere with main grounds are between battery, chassis and engine block.
    – F Dryer
    Commented Sep 15, 2023 at 20:06
  • I agree with F Dryer in all points. Additionally: run the VCDS graph multiple times using about the same pedal speed and duration. If the dropouts occur at about the same points in the graph each time, look for a mechanical problem with the pedal encoder. If the dropouts are truly random, look for a problem in the electronics such as the +5V supply or a loose connection, or even an errant program loop in the ECM that is sapping the +5V every X milliseconds. You can try disconnecting the battery for 30 minutes to cause the ECM to cold boot and possibly remedy such a program loop.
    – MTA
    Commented Sep 15, 2023 at 22:27

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You mention in your post that you replaced the throttle body. Did you also replace the throttle position sensor?

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