Don Mc Posted June 18, 2021 Share Posted June 18, 2021 I'm having a problem with the knock sensor in my car Ed17 is showing 7242 and it never moves is it a bad knock sensor Link to comment Share on other sites More sharing options...
Padgett Posted June 18, 2021 Share Posted June 18, 2021 (edited) Knock sensor is supposed to reset the count when the ignition is turned off and then increment from zero on next start. There is usually a burst of 50-70 on startup. Can usually make it count by rapping on the firewall side valve cover with the handle from a big screwdriver. If yours is not zero when you turn the ignition on but do not start try cycling the negative battery terminal (off for 15 sec then back on) and see if it zeros. BTW max is supposed to be 255 (single 8 bit byte). 7242 constant sounds more like a prom ID (ED99). Edited June 18, 2021 by Padgett Link to comment Share on other sites More sharing options...
Don Mc Posted June 18, 2021 Topic Author Share Posted June 18, 2021 Just checked it It does start out at 0 and it was up to 276 when I shut it off. Link to comment Share on other sites More sharing options...
Don Mc Posted June 18, 2021 Topic Author Share Posted June 18, 2021 Just drove home from work it was 0when I left and it was over 900 when I got home. Link to comment Share on other sites More sharing options...
Padgett Posted June 18, 2021 Share Posted June 18, 2021 Maybe 90 is 2 bytes, have an 88. That sounds like something is knocking, I'd put a stethoscope (or long screwdriver) on the block and see what I heard. I'd also check for a failing balancer. 1 Link to comment Share on other sites More sharing options...
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