G3600 A4 Engines Electrohydraulic System Oil Pressure Is Low Caterpillar


Electrohydraulic System Oil Pressure Is Low
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1.1. Probable Causes
2.1. Recommended Actions

Use this procedure in order to troubleshoot a low oil pressure in the electrohydraulic system. Also, use this procedure if one of the following event codes is active or logged.

Table 1
J1939 Code and Description  Comments 
1762-1
Hydraulic Pressure : Low - most severe (3) 
The pressure sensor for the electrohydraulic actuator system detects pressure less than 700 kPa (102 psi) for more than 10 seconds.
The engine will shut down. 

Probable Causes

  • Codes

  • Relief valve

  • Oil pressure

Recommended Actions

Table 2
Troubleshooting Test Steps  Values  Results 

1. Check for Codes

A. Connect Cat® Electronic Technician (ET) to the service tool connector.

B. Look for active codes that are associated with the system for the event code.
 

Codes
 

Result: An associated code is active.

Repair: Troubleshoot any associated codes before continuing with this test.

Result: A code is active or logged.

Proceed to Test Step 2.
 

2. Check the Pressure Relief Valve Setting
 

Relief Valve
 

Result: The pressure relief valve setting is OK.

Proceed to Test Step 3.

Result: The pressure relief valve setting is NOT OK.

Repair: Adjust the pressure relief valve. Refer to Testing and Adjusting, "Engine Governing - Adjust" for additional information.

If the problem is not resolved, proceed to Test Step 3.
 

3. Inspect the Pressure Relief Valve

If the pressure relief valve is dirty, the valve can become stuck. If the pressure relief valve is stuck in the open position, the hydraulic oil pressure will be too low.

A. Check the relief valve that is located on the aftercooler.

B. Check the relief valve that is located on the hydraulic pump for leakage and/or adjustment.
 

Relief Valve
 

Result: The pressure relief valves are OK.

Proceed to Test Step 4.

Result: The pressure relief valves are NOT OK.

Repair: Clean or replace pressure relief valve. Adjust the pressure relief valve, refer to Testing and Adjusting, "Engine Governing - Adjust" for additional information.

If the problem is not resolved, proceed to Test Step 4.
 

4. Check for Low Hydraulic Oil Pressure

A. Check the hydraulic oil level.

B. Use a gauge to check the oil pressure of the electrohydraulic system at the outlet for the hydraulic pump while the engine is cranking.

C. Compare the pressure to the pressure that is described in Testing and Adjusting, "Engine Governing - Adjust".

D. Use a gauge to check the oil pressure of the electrohydraulic system at the outlet for the hydraulic pump while the engine is at normal operating temperature, when possible.

E. Compare the pressure to the pressure that is described in Testing and Adjusting, "Engine Governing - Adjust".
 

Oil Pressure
 

Result: The oil pressure is NOT OK.

Repair: Inspect the electrohydraulic system for leaks. Inspect the hydraulic pump. Make repairs, as needed.

Verify that the repair eliminated the problem.
 

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).