Anybody have any experience with troubleshooting the Control Module in a JD 4100?
This problem started off with the tractor turning over but not starting. Traced issue to fuel solenoid not pulling on. Checked out fuel solenoid with an available 12V source on the tractor and determined it was working OK and traced issue to the K3 Fuel Solenoid relay. Checked out relay inputs and outputs and found that it was not getting 12V across the coil to close the contacts. Traced issue back to control module.
From my understanding of the control logic there should be a momentary 12V supplied by the control module between the pink wire and the gray wire (relay coil ground path). During this time the relay contact closes providing the pull-in voltage to the fuel solenoid. The gray wire ground path is supposed to open after 1 second which terminates the 12V to the relay and opens the contact. By this time the solenoid is provided with a low-current 12V source which will hold the fuel solenoid in to keep the tractor running.
So found another momentary 12V source (starter relay) to get the fuel solenoid pulled in and get the tractor started so could checkout the control module. The fuel solenoid hold-in voltage source (red wire) appears to be good (shows battery voltage).
Opened up control module and measured voltage between pink wire and gray wire (ground). With key in 徹n position voltage went to ~135 mV. Then started tractor. Voltage drops to near ~20mV momentarily and then started climbing. After several seconds (40-50 sec) it reached 200 mV and then dropped to zero again and started cycle over - always topping out at 200mV before dropping back to zero. So definitely not enough voltage to close the K3 contacts.
So I think the issue is with the control module and wondering what options there might be for troubleshooting of the control module - or is a replacement in the cards?
Thanks in advance.
This problem started off with the tractor turning over but not starting. Traced issue to fuel solenoid not pulling on. Checked out fuel solenoid with an available 12V source on the tractor and determined it was working OK and traced issue to the K3 Fuel Solenoid relay. Checked out relay inputs and outputs and found that it was not getting 12V across the coil to close the contacts. Traced issue back to control module.
From my understanding of the control logic there should be a momentary 12V supplied by the control module between the pink wire and the gray wire (relay coil ground path). During this time the relay contact closes providing the pull-in voltage to the fuel solenoid. The gray wire ground path is supposed to open after 1 second which terminates the 12V to the relay and opens the contact. By this time the solenoid is provided with a low-current 12V source which will hold the fuel solenoid in to keep the tractor running.
So found another momentary 12V source (starter relay) to get the fuel solenoid pulled in and get the tractor started so could checkout the control module. The fuel solenoid hold-in voltage source (red wire) appears to be good (shows battery voltage).
Opened up control module and measured voltage between pink wire and gray wire (ground). With key in 徹n position voltage went to ~135 mV. Then started tractor. Voltage drops to near ~20mV momentarily and then started climbing. After several seconds (40-50 sec) it reached 200 mV and then dropped to zero again and started cycle over - always topping out at 200mV before dropping back to zero. So definitely not enough voltage to close the K3 contacts.
So I think the issue is with the control module and wondering what options there might be for troubleshooting of the control module - or is a replacement in the cards?
Thanks in advance.
