New Holland WorkMaster 50 Service Manual page 927

DTC 3D4-02-ECU internal failure - ECU shutdown test failure
Control Module : ECU
Context:
The Engine Control Unit (ECU) A-9000 performs a series of "shut-off path" tests which deactivates all power stages
relevant to fuel injection if certain ECU A-9000 errors are detected. If an incorrect response to the power stage supply
(CY320) is detected during this test, this fault will occur.
Solution:
1. Check the ECU A-9000 for the appropriate software and re-flash, if necessary.
A. If the fault has been resolved, return the machine to service.
B. If the fault has not been resolved, escalate an ASIST concern.
Electrical systems - FAULT CODES
47866583_ 02/12/2015
55.12 [55.DTC] / 206