# JD 8520 cranks runs and shuts down in 2 to 4 seconds



## lexc269_6243 (Oct 28, 2021)

there are no codes that indicates why the engine would shuting down all fuses are good I swap out ECM Relay checked power and ground to ECM b1,2 c3,4 pins. There is loss of voltage on #1 high pressure fuel solenoid the. #2 didn't seem to change but as #1 fell below 1.0v the engine shuts off like a protection event. I went down this rabbit hole DTC, PCU 05 and PCU 04 checking the address on ECU #24 and #25 they are the same value at 199-198 but they match. andmanual says there is a default in place so didn't think it was an issue. Now puzzling 2 me there is no reference to PCU 05 DTC in the manual. I have started checking can bus and found the only correct can bus signal is impelment the other two on service adviser port are2.4- 2.5v both are the same numbers. I stopped right there last night would the terminators passive and not sure what the other is called will they short can bus hi and low together. Need directions please I've burnt my brain crash courses on 8520 till I'm cross eyed. Have I missed anything. Also motor runs as soon as it turns over I spent half a day freeing up check valves and priming fuel system. I think I have it primed. Help


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## lexc269_6243 (Oct 28, 2021)

lexc269_6243 said:


> there are no codes that indicates why the engine would shuting down all fuses are good I swap out ECM Relay checked power and ground to ECM b1,2 c3,4 pins. There is loss of voltage on #1 high pressure fuel solenoid the. #2 didn't seem to change but as #1 fell below 1.0v the engine shuts off like a protection event. I went down this rabbit hole DTC, PCU 05 and PCU 04 checking the address on ECU #24 and #25 they are the same value at 199-198 but they match. andmanual says there is a default in place so didn't think it was an issue. Now puzzling 2 me there is no reference to PCU 05 DTC in the manual. I have started checking can bus and found the only correct can bus signal is impelment the other two on service adviser port are2.4- 2.5v both are the same numbers. I stopped right there last night would the terminators passive and not sure what the other is called will they short can bus hi and low together. Need directions please I've burnt my brain crash courses on 8520 till I'm cross eyed. Have I missed anything. Also motor runs as soon as it turns over I spent half a day freeing up check valves and priming fuel system. I think I have it primed. Help


well I figured I would respond to this repair and chain of events leading up to the tractor running correctly. we sent the ECM In for a up to date flash software and the tractor started up and ran a 1/4 mile to the shop and started the same thing again I found the can bus Terminator passive unplugged it tested voltage and plugef ot back up and the tractor worked for 1/2 a day replaced the passive can bus Terminator the tractor has not shut down again . pulling a peanut combine over 700 acres to finish the harvest. the bill for John Deere to come out and claim the ecm was needing a flash to repair it was north of $2000 .the can bus Terminator was. $130 .


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## pogobill (Jan 31, 2012)

Thanks for sharing the outcome.


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