CONTROL GP-ELECTRONIC 3408157 - Caterpillar

Personal injury can result from contact with hot hydraulic oil and from contact with hydraulic oil that is under high pressure.Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. The hydraulic oil pressure must be released before any service on the hydraulic system is performed or serious personal injury could occur.Verify that all of the work tools have been completely lowered to the ground. Release the hydraulic oil pressure at the hydraulic tank through the breaker relief valve when the breaker relief valve is cool enough to touch with your bare hand. Verify that the hydraulic oil is cool before you begin to remove any hydraulic components or hydraulic lines.
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, "Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids.Dispose of all fluids according to local regulations and mandates.
Two people are needed in order to complete the test procedure.Note: Use the information in the reference to prepare the machine for this test. Also, use the information in the reference to relieve any system pressure that may be present in the hydraulic system.Reference: For the correct procedure to prepare the machine for this test, refer to Testing and Adjusting, "Machine Preparation for Troubleshooting" for the machine that is being serviced.Reference: For the correct procedure to relieve any hydraulic oil pressure that may be present in the hydraulic system, refer to Testing and Adjusting, "System Pressure - Release" for the machine that is being serviced.
Table 1
Required Tools    
Part Number     Description     Qty    
8T-0860     Pressure Gauge     1    
7X-2444     Swivel Tee     1    
187-3547     Fitting     1    
Place the machine on level ground.
Illustration 1 g01052558
Location of the switch for the hood on early machines
Illustration 2 g01162235
Location of the switch for the hood on later machines
Illustration 3 g01074453
Open the hood for the engine compartment.Note: The switch for the hood is located underneath the right armrest on early machines. On later machines, the switch for the hood is located on the right hand console.
Illustration 4 g00827465
Hydraulic lockout control on early machines
Illustration 5 g01162814
Hydraulic lockout control on later machines
Move the hydraulic lockout control to the LOCKED position.
Shut off the engine.
Release all the system hydraulic pressure. For information on the correct procedure to release pressure, refer to the reference at the beginning of this test.
Illustration 6 g01070750
(1) Cylinder (hood) (engine side)
Disconnect the hose from cylinder (1) on the engine side. Install the swivel tee with fitting. Attach the pressure gauge to the fitting.
Start the engine. Operate the engine at low idle.
Move the switch for the hood to the OPEN position.
Read the pressure gauge. The pressure should be 20685 kPa (3000 psi). If the pressure is incorrect proceed to Step 10. If the