Frank Batista Posted May 18, 2017 Share Posted May 18, 2017 My engine rpm goes down while driving wont shut off ....just keep idling few seconds then comes back on ...no check engine light....same while cruising or pedal....any help ??? Quote Link to comment https://www.bigmacktrucks.com/topic/49875-mack-2007-cxn613/ Share on other sites More sharing options...
Mackpro Posted May 18, 2017 Share Posted May 18, 2017 If you can't shut off engine and the throttle pedal won't work and your idling at 900 rpm , the vehicle control unit VECU has lost coms with the engine ECM on the 1939 data line yellow and green twisted wires Quote Link to comment https://www.bigmacktrucks.com/topic/49875-mack-2007-cxn613/#findComment-370191 Share on other sites More sharing options...
Eastcoastdiesel Posted May 26, 2017 Share Posted May 26, 2017 Give me some other symptoms of while driving it. Is it bucking when you lose rpms? Smoke? Continuous or Spotty? Also, it is just a feature on those trucks to not shut off when you turn the key off.It's nothing bad, just something the engineers have given them. Quote Link to comment https://www.bigmacktrucks.com/topic/49875-mack-2007-cxn613/#findComment-370803 Share on other sites More sharing options...
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