New Holland WorkMaster 50 Service Manual page 966

DTC 559-12-Fuel metering unit has an over-temperature error
Control Module : ECU
Context:
The Engine Control Unit (ECU) monitors the fuel metering unit Y-9000 signal circuit for an over temperature/current
condition. If the ECU A-9000 detects an over temperature/current condition in the fuel metering unit Y-9000 signal
circuit, this fault will occur.
Cause:
The ECU A-9000 has detected an over temperature/current condition in the fuel metering unit Y-9000 signal circuit.
Possible failure modes:
1. Faulty fuel metering unit Y-9000 wiring, short to a voltage source.
2. Faulty fuel metering unit Y-9000, internal failure.
3. Faulty ECU A-9000, software.
Solution:
1. Verify fault is present and active.
Use the Electronic Service Tool (EST) to check the status of this fault.
A. If the fault is present and active, continue with Step 2.
B. If the fault is no longer present or in an inactive state, the fault may be intermittent and not currently active.
Continue with Step 5.
2. Test the fuel metering unit Y-9000 internal resistance.
Disconnect the engine harness (EN) from the fuel metering unit Y-9000 at connector X-9007.
Use a multimeter to measure the resistance on the fuel metering unit Y-9000 pins :
From
X-9007 pin 1
A. If there is between 2.6 - 3.2 Ω, leave connector X-9007 disconnected and continue to Step 3.
B. If there is not between 2.6 - 3.2 Ω, the fuel metering unit Y-9000 has failed. Replace the fuel metering unit
Y-9000.
3. Check the fuel metering unit Y-9000 low side driver wiring for a short to battery condition.
With the key in the OFF position, use a multimeter to perform the following voltage check on the engine harness
(EN) side :
From
X-9007 pin 1
With the key in the ON position, use a multimeter to perform the following voltage check on the engine harness
(EN) side :
From
X-9007 pin 1
A. If there is voltage, there is a short circuit to battery or switched battery in the fuel metering unit Y-9000 low
side driver circuit wiring. Use the appropriate service manual, if necessary, to locate and repair the shorted
conductor.
Electrical systems - FAULT CODES
To
X-9007 pin 2
To
Chassis ground
To
Chassis ground
47866583_ 02/12/2015
55.12 [55.DTC] / 245
Value
There should be between 2.6 - 3.2 Ω
at approximately 20.0 °C (68.0 °F).
Value
There should be no voltage.
Value
There should be no voltage.