LINK 0034872 - Caterpillar

The Crossover Relief/Makeup Valve Is Leaking
Test and adjust the crossover relief and makeup valves. Refer to Testing and Adjusting, KENR8558, "Steering Hydraulic Circuit - Test and Adjust".Oil from the high-pressure side of the steering loop may leak across to the low-pressure side of the loop under one of the following conditions:
The relief function or the makeup function of one of the valves is stuck open
One of the valves springs is weak
One of the valves springs is broken
One of the valves springs is misadjustedIf one of the conditions listed above exists, the necessary high pressure may not be possible. The pressure may not be too low in one or both sides of the steering loop.Test the mechanical neutral position for the steering pump control valve. Refer to Testing and Adjusting, KENR8558, "Neutral Adjustment (Steering Pump) - Test and Adjust". If the neutral position of the steering pump control valve is incorrect (off-center while in the NO STEER condition): the steering pump control valve will command the actuator piston to move off-center when there is no steering request. This condition may cause the machine to stray from straight-line travel in a NO STEER condition. This condition may cause the machine to steer more sharply in one direction than the other.The Steering Pump Controls Are Suspect
With the Monitoring System or Caterpillar Electronic Technician (Cat ET), check for event codes associated with the steering lever position sensors.Any steering position sensors failure will result in a "Level 3 Warning" indicating an immediate safe machine shutdown. That action must be performed immediately, in a safe manner and at a safe place, before machine damage or personnel injury occurs.Note: Event codes are listed above.If an event code for the steering system is logged, continue with the following procedures.
Check the monitoring system or Cat ET for fault codes related to "Steering Position Sensor 1", "Steering Position Sensor 2", or "Steering Position Sensor 3".Ensure that a problem with the steering lever position sensors is not causing the steering pump to operate improperly. If the signals from the steering position sensors are incorrect, the ECM may not be commanding the solenoid to energize properly. The ECM may not be commanding the solenoid to de-energize properly. Correct any problems with these components, then check to see if the symptom is resolved.With Cat ET, perform the calibration routine for the "Steering Control Position Sensors".
With Cat ET, perform the calibration routine for the "Steering Control Position Sensors".This procedure calibrates the two position sensors. Then the ECM can correctly interpret the sensors signals and properly control the steering pump control solenoids.If the sensors are not calibrated correctly, false signals will be sent to the machine ECM. The condition will cause the ECM to try and steer when no steering request is present. The ECMmay also receive signals to steer in one steering direction but not the other.
With the monitoring system, check the signal "Duty Cycle" from the steering lever position sensors.View the status of the steering lever position sensors in order to