New Holland WorkMaster 50 Service Manual page 793

Disconnect the vehicle harness (VE) from the ECU A-9000 at connector X-9121.
With the key in the OFF position, use a multimeter to perform the following continuity check on vehicle harness
(VE) side :
From
X-9139 pin D
A. If there is continuity, there is a short circuit in the fuel injector number 3 Y-9003 wiring in the vehicle harness
(VE) between wires VE-9128 and VE-9127. Use the appropriate service manual, if necessary, to locate and
repair the shorted conductor.
B. If there is no continuity, continue with Step 5.
5. Check the ECU A-9000 voltage supply wiring.
Disconnect the vehicle harness (VE) from the ECU A-9000 at connector X-9122.
With the key in the ON position, use a multimeter to perform the following voltage checks from the vehicle harness
(VE) side :
From
X-9122 pin K03
X-9122 pin K05
X-9122 pin K01
A. If there is approximately 12.0 V, leave connector X-9122 disconnected and continue to Step 6.
B. If there is not approximately 12.0 V, there is a faulty ECU A-9000 voltage supply. Use the appropriate service
manual, if necessary, to locate and repair the failed conductor.
6. Check the ECU A-9000 ground supply.
With the key in the OFF position, use a multimeter to perform the following continuity check on the vehicle harness
(VE) side : :
From
X-9122 pin K02
X-9122 pin K04
X-9122 pin K06
A. If there is no continuity, there is a faulty ECU A-9000 ground supply. Use the appropriate service manual, if
necessary, to locate and repair the failed conductor.
B. If there is continuity, check the ECU A-9000 for the appropriate software and re-flash, if necessary.
7. Visually inspect the relevant harnesses and connectors for damage, bent or dislocated pins, corroded terminals,
or broken wires. Verify that the connectors are fully installed. Flex the harnesses involved to reveal intermittent
breaks or shorts in the wiring concerned. Operate the machine while you monitor the display.
A. If you find damage or the display indicates other than normal display readings, then repair the damage discov-
ered during the inspection or locate and repair the other than normal display condition and verify that the error
has been resolved.
B. If you do not find damage and the display indicates only normal readings, then erase the fault code and continue
operation.
Wiring harnesses - Electrical schematic sheet 04 – Engine Control Unit (ECU) vehicle connector
(55.100.DP-C.20.E.04)
Wiring harnesses - Electrical schematic sheet 05 – Engine Control Unit (ECU) engine connector
(55.100.DP-C.20.E.05)
Wiring harnesses - Electrical schematic sheet 06 – Engine control and fuel injection (55.100.DP-C.20.E.06)
Electrical systems - FAULT CODES
To
X-9139 pin C
To
chassis ground
chassis ground
chassis ground
To
chassis ground
chassis ground
chassis ground
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55.12 [55.DTC] / 72
Value
There should be no continuity
Value
There should be approximately
12.0 V
There should be approximately
12.0 V
There should be approximately
12.0 V
Value
There should be continuity.
There should be continuity.
There should be continuity.