New Holland WorkMaster 50 Service Manual page 968

Electrical systems - FAULT CODES
DTC 58C-03-Throttle valve actuator will not open to commanded
position
Control Module : ECU
NOTE: Once repaired, this fault may take up to up to 10 min of operation to reset.
Context:
The Engine Control Unit (ECU) A-9000 monitors the Throttle Valve Actuator (TVA) Z-9001. The TVA Z-9001 provides
the ECU A-9000 with a feedback using a position sensor. If the ECU A-9000 determines that there is a positive
deviation between the required and measured position, this fault will occur. If this fault is active, the ECU A-9000 will
command the TVA Z-9001 to open and close at a fast rate in order to attempt to "unblock " the actuator. This fault is
not caused by a wiring failure. It is likely caused by an obstruction to the throttle valve flap or excessive carbon build
up on the throttle valve seat. For more information regarding TVA Z-9001 inspection, see Throttle Valve Actuator
(TVA) - Inspect (55.014).
Cause:
The ECU A-9000 has detected a positive deviation between the required and measured position of the TVA Z-9001.
The desired throttle valve position can not be reached.
Possible failure modes:
1. Faulty throttle valve actuator Z-9001, sticking or blocked.
2. Faulty throttle valve actuator Z-9001, internal failure.
3. Faulty ECU A-9000, software.
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