New Holland Workmaster 50, Service Manual

Page: 950 / 1067

Electrical systems - FAULT CODES
DTC 48D-02-Throttle valve actuator control circuit open
Control Module : ECU
Context:
The Engine Control Unit (ECU) A-9000 monitors the throttle valve actuator Z-9001 output 1 and output 2 h-bridge
circuits. If the ECU A-9000 detects a an open circuit in the throttle valve actuator Z-9001 output h-bridge circuits, this
fault will occur.
Cause:
The ECU A-9000 has detected an open circuit in the throttle valve actuator Z-9001 output h-bridge circuits.
Possible failure modes:
1. Faulty throttle valve actuator Z-9001 wiring, open circuit.
2. Faulty throttle valve actuator Z-9001 , 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 4 .
2. Check the throttle valve actuator Z-9001 h-bridge engine harness (EN) wiring for an open circuit.
Disconnect the engine harness (EN) from the throttle valve actuator Z-9001 at connector X-9011 .
Disconnect the engine harness (EN) from the ECU A-9000 at connector X-9001 .
With the key in the OFF position, use a multimeter to perform the following continuity check for an open circuit at
the engine harness (EN) side :
From To Value
X-9011 pin 6 X-9001 pin A49 There should be continuity.
X-9011 pin 2 X-9001 pin A34 There should be continuity.
NOTE: Wiggle the harness during the check to promote an intermittent electrical connection.
A. If there is no continuity, there is an open circuit in the throttle valve actuator Z-9001 engine harness (EN)
h-bridge circuit. Locate and repair the broken conductor.
B. If there is continuity, leave connector X-9011 disconnected and continue to Step 3 .
3. Replace the throttle valve actuator Z-9001.
Use the Electronic Service Tool (EST) to check the status of this fault.
A. If the fault is no longer active, return the machine to service.
B. If the fault is still active, check the ECU A-9000 for the appropriate service manual and re-flash, if necessary.
4. 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.
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