Are there any alternatives for scoping the primary coil on a COP system other than using a low amp probe? I'm guessing backprobing doesn't work since the ignition control module is built into the coil and it receives a digital signal. Am I stuck looking at secondary or current ramp on the primary?

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    You best bet with coil on plug units is to transfer them from one cylinder to another and see if the problem follows or stays where it's at. I've seen one other way, where you send a signal to the coil via something other than the PCM and see how it fires. Not very scientific in either case, but will work. Not answering your question about the how, so leaving this as a comment. Commented Jun 9, 2016 at 0:10
  • @Pᴀᴜʟsᴛᴇʀ2 I have flag pickups but sometimes the signal is too weak or there's too much interference to get a good secondary signal. I'd like to be able to backprobe a wire and view the primary wave form like you can with older ignition coils. Without having to unbolt stuff. Obviously swapping coils can be a good way to check and sometimes can only take a few minutes to do but when coils aren't accessable I'd like to be able to pierce the harness or backprobe and get a look at a coil.
    – Ben
    Commented Jun 9, 2016 at 0:17
  • My understanding, like you said, there's no way to do it with these newer coil ons, due to the electronics being in the coil themselves. Commented Jun 9, 2016 at 0:32

1 Answer 1


Check out the General Technologies TA500. This tool is quite inexpensive (for its incredible capabilities) and very flexible. Perhaps not for the DIY set, but there's no probing involved and it allows you to do coil-to-coil comparisons in seconds.


  • Now I realize the OP is Ben ... you NEED this. I get no commission; I swear.
    – SteveRacer
    Commented Jun 9, 2016 at 4:09

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