Caterpillar 320c Fault codes list

By | 05/06/2018

Caterpillar 320c Excavator CLM Troubleshooting Diagnostic Codes (Fault codes list)

Caterpillar 320c Fault Codes List

Caterpillar 320c

See also: Caterpillar PDF Service Manuals

Illustration 1
Example Of A Typical Troubleshooting Procedure

(1) Preparations

(2) Description of the problem

(3) Error code on the display

(4) Items that require checking

(5) Probable cause and solution


Illustration 2
Diagram Of Terminology For The Troubleshooting Procedures

(6) Number of the terminal in the connector

(7) Indication of the short circuit

(8) Number of the connector

(9) “M” Male “F” Female

  1. Description (Items that require checking)
  2. Measurement of Voltage

O (A) – (B) : 24 V

Voltage is measured at the later terminal. For example, the red test pin + is connected to terminal “A” and the black test pin – is connected to terminal “B”.

  1. Meaning of Symbols
  2. The following list describes the meaning of specific symbols:
  • “C-ground” : Ground terminal for the chassis
  • “P-ground” : Ground terminal for the platform
  • “R-ground” : Ground terminal for the relay panel
  • “Cab-ground” : Ground terminal for the cab
  1. Preliminary Check
  2. Connector


Check the connection of the connector before a troubleshooting procedure is performed. Inspect the connector for moisture. Moisture in a connector can cause a poor connection. Ensure that the connectors are mating correctly. Ensure that the pins in the connector are secure.

  1. Continuity

Ensure that continuity is present between the following items:

  • “C-ground” – “P-ground”
  • “C-ground” – “R-ground”
  • “P-ground” – “Cab-ground”

Turn the disconnect switch to the OFF position before you perform the continuity checks. The power is OFF in order to prevent damage to the tester and the circuit.

  1. Preparation
  2. Turn the key start switch to the OFF
  3. The hydraulic control lever is in the LOCKED
  4. Ensure that the controller, the harnesses and the connectors are

Note: Ensure that disconnected wires do not contact the machine in order to avoid damage to electrical components when power is applied.

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