Troubleshooting a system requires additional information from the machines service manual. The additional manuals that may be required are listed below.
- Electrical System Schematic
- Electrical System Schematic Supplement
- Operation and Maintenance Manual
- Power Train Trouble Shooting, Testing and Adjusting
- Parts Manual
When the troubleshooting procedure instructs you to “REPAIR THE HARNESS”, use the electrical system schematic for the machine that is being serviced to trace the circuit.
Perform continuity checks at the harness connectors in order to locate harness failures.
At the connectors of the components, always check the ground circuit. Less than 5 ohms of resistance is required between the ground contacts of the connector and the frame ground. Excessive ground resistance that is greater than 5 ohms can cause incorrect diagnosing of problems.
During troubleshooting, inspect all connections before any component is replaced. If these connections are not clean and tight, permanent electrical problems or intermittent electrical problems can result. Check that the wires are pushed into the connectors completely. Make sure that the connections are tight before other tests are made.
When you perform wiring harness tests, do not puncture the wire insulation. Use test leads in a manner that does not damage the wire insulation to troubleshoot the harness .
If damaged wire insulation is found during troubleshooting, repair the damage. Seal the damaged wires with an RTV Silicone Sealant. Cover the sealant with two layers of electrical tape.
Failure of an electrical component can cause the failure of other components. Always attempt to correct the cause of an 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 test are made to the remote control system, visually inspect the remote control system for parts that have damage. Check the steering and bucket control valve for oil leaks.
Preparation for Troubleshooting
Sudden movement of the machine or release of oil under pressure can cause serious injury to persons on or near the machine.
To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system.
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 by a doctor familiar with this type of injury.
Always use a board or cardboard when checking for a leak.
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.
Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products.
Dispose of all fluids according to local regulations and mandates.
Note: Permit only one operator on the machine. Keep all other personnel away from the machine or within the sight of the operator.
- Move the machine to a hard, level surface. Lower the work tool to the ground.
- Place the transmission direction and speed control in the NEUTRAL position and in any speed position. Engage the steering and transmission lock lever on steering controls.
- Engage the parking brake. Place blocks in front of the tracks and behind the tracks.
- Stop the engine.
- Move the key start switch to the ON position.
- Move the joystick control lever through the full range of travel. Any pressure that may be present in the implement hydraulic system will be relieved. Place the joystick control lever in the HOLD position.
- Move the steering control several times in both directions to release the pressure in the steering system.
- Depress the brake pedal repeatedly. Any pressure that may be present in the braking system will be relieved.
- Depress the breaker relief valve on the hydraulic tank to release the pressure in the hydraulic tank.
- Remove the key from the ignition and place a "Do Not Operate" tag on the ignition switch.
- Turn the battery disconnect to the OFF position. Either remove the battery disconnect key or lock out the battery disconnect to disable it from being turn to the "ON" position.