Troubleshooting

Machine Preparation for Troubleshooting

SMCS Code: 7600-035-ZM

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Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the steering system.

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Personal injury or death can result from escaping fluid under pressure. Escaping fluid under pressure, even a very small pin-hole size leak, can penetrate body tissue and cause serious injury and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak.

1. Move the machine to a smooth, horizontal location that is away from operating machines and away from personnel.

NOTE: Permit only one operator on the machine. Keep all other personnel away from the machine or in the operator's sight.

2. Put the transmission control in the NEUTRAL position and any speed position. Engage the primary steering/transmission lock lever (STIC steer machines) or the transmission neutral lock (wheel steer machines).

3. Engage the parking brake. Place wheel blocks in front of the wheels and behind the wheels.

4. Lower the bucket or the attachments to the ground.

5. Install the steering frame lock link.

6. Stop the engine.

7. Move the hydraulic control lever several times through the full range of travel. This will release any pressure that may be present in the implement hydraulic system.

8. Move the STIC steering control several times in both directions to release the pressure in the steering system.

9. Release the braking system oil pressure.

Reference: For the correct procedure to release the braking system oil pressure, refer to Systems Operation, Testing and Adjusting, "Remove Oil Pressure from Brake System" for the machine that is being serviced.

10. Depress the breaker relief valve on the hydraulic tank in order to release the hydraulic oil pressure.

11. The pressure in the hydraulic system has been released. Lines and components can be removed.

General Troubleshooting Information

SMCS Code: 7600-035-ZM

Troubleshooting the remote control system requires additional information from the machine Service Manual. The Electrical System Schematic, the Parts Manual and the Operation and Maintenance Manual are required support material.

When the troubleshooting procedure instructs to REPAIR THE HARNESS, use the Electrical System Schematic in the machine Service Manual to trace the circuit. Perform continuity checks at the harness connectors to locate harness failures. At the connectors of the components, always check the ground circuit. Less than five ohms of resistance is required between the ground contacts of the connector and the frame ground. Excessive ground resistance, greater than five ohms, can cause incorrect diagnosing of problems.

During troubleshooting, inspect all component and harness connections before any component is replaced. If these connections are not clean and tight, they can cause electrical problems, either permanent or intermittent (come and go). Check that the wires are pushed into the connectors completely. Make sure the connections are tight before other tests are made.

Use only the recommended probe tools in the troubleshooting process. Always avoid puncturing the wire insulation. Puncturing the wire can result in a corrosion problem.

Failure of an electrical component can cause, or be caused by the failure of one or more other components. Always attempt to find and correct the cause of electrical system failure before you replace a component.

NOTE: Before any tests are made to the remote control system, operate the machine manually. Check the machine systems for correct operation. If any problems occur on manual operation, refer to the relevant machine systems section of the machine Service Manual for troubleshooting information.

NOTE: Before any tests are made to the remote control system, visually inspect the remote control system for parts that have damage. Check the remote control hydraulic interface for oil leaks.

Service Tools

SMCS Code: 0785

The following service tools should be used to aid in troubleshooting the electrical system.

For instructions on servicing Sure Seal connectors, see Special Instruction, SMHS7531. For instructions on servicing the Deutsch "DT" Type connectors, see Special Instruction, SEHS9615.

Use the digital multimeter for making continuity (resistance) checks or voltage measurements. For instructions on use of the 6V-7070 Digital Multimeter, see Special Instruction SEHS7734. The 7X-1710 Multimeter Probe Group is used for measuring the voltage at connectors without needing to disconnect the connectors. The probe cables are pushed into the back of the connector alongside the wire.

NOTE: Use of continuity testers (such as 8T-0500), or voltage testers (such as 5P-7277) are not recommended for use on present-day Caterpillar electrical circuits, except for harness tests.

Remote Control System Troubleshooting

SMCS Code: 7600-035-ZM

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Personal injury or death can result from improperly checking for a leak. Always use a board or cardboard when checking for a leak. Escaping fluid under pressure, even a pin hole size leak, can penetrate body tissue, causing serious injury and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury.

This section provides probable causes to known problems. Since there may be several probable causes, specific inspections or instrument tests may be recommended. These inspections and tests will help identify the causes that are most probable.

Troubleshooting Flow Chart