Medium and Heavy Trucks
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Hi Lamar. My name is***** will be glad to help. The Idle speed is programmed into the ECM so Cummins Insite will need to be plugged in to monitor and check the current parameters, sensor signals and settings. If the sensors and harness are good then the problem will be ECM software related.
Hi Lamar. The ECM controls low and high RPM. I did not specifically say it was the ECM but without Cummins insite or being plugged into the engine and reading live data through a comparable scan tool you can not see the current programming and settings. You need to be able to see what the programming is set at for PTO settings. These are changable settings programmed in the ECM. you could have a speed sensor or throttle position sensor problem. Try calibrating the throttle position sensor to the new ECM if you have not already. Key on, push the fuel pedal slowly to the floor and then all the way back up 3 times to calibrate. Then see if your problem is corrected. Also there could be a fuel return restriction causing this. Try the TPS calibration first since you may not have done this when installing the ECM