312C, 315C, 318C, 319C, 320C, 321C, 322C, 325C, 330C and M325C Excavators and 325C MHPU and 330C MHPU Mobile Hydraulic Power Units Engine and Pump Control – V2 – Governor Actuator Sweep – Test

This mode is used to confirm the activation of the governor actuator.

Note: The 325C, M325C MH, and 330C series does not have a governor actuator.

Table 1
Required Tools    
146-4080 Digital Multimeter    
188-8589 Test Harness    

Illustration 1 g00778226

Governor Actuator For 312C

(1) Governor actuator

(2) Governor cables

(3) Connector

Illustration 2 g00778227

Governor Actuator For 315C

(1) Governor actuator

(2) Governor cables

(3) Connector

Illustration 3 g00778702

Governor Actuator For 319C, 320C series and 322C

(1) Governor actuator

(2) Governor cables

(3) Connector

Illustration 4 g00986349

Governor Actuator for 321C

(1) Governor actuator

(2) Governor Cables
  1. Stop the engine and disconnect the connector (3) for the governor actuator. Connect the test harness to the connector.
  1. Place the backup switch in the AUT position.
  1. Turn the engine start switch to the ON position. Do not start the engine. Select the sweep test for the governor actuator.
  1. Enter the service mode. Perform the device test according to “ENG SWEEP”.

    Illustration 5 g00690421

  1. Use a digital multimeter to measure the frequency of the speed command signal while the system is in operation. See the above illustration. The duty cycle should be approximately 45% to 90%. A low duty cycle means a low engine speed. A higher duty cycle means a high engine speed. The pulse width is narrow at low speeds and the pulse width is wide at high speeds.
  1. An abnormality is present when the pulse width is not correct. A failure may exist in the harness, the governor actuator or the controller.
  1. The speed of the engine will vary in synchronization with the reciprocating drive. If the controller is operating properly, the engine speed will vary between the high idle and the low idle. The governor actuator may be installed incorrectly or the governor actuator may not be operating correctly, if the engine speed is not correct. Also, the engine may be operating incorrectly.