VALVE AS-RELIEF 3125857 - Caterpillar

Illustration 1 g02458902
Connections of the compressor for the air conditionerThis diagnostic code is associated with the air conditioner compressor. This diagnostic code means that the voltage to the compressor is lower than expected.The possible causes of this diagnostic code are listed:
The compressor for the air conditioner has failed.
The Accessory Power Converter (APC) has failed.
Accessory Power System cable between the APC and A/C Compressor is damagedNote: This diagnostic code will not occur if the cable is open. The compressor would not communicate in this instance.Test Step 1. USE THE MESSAGE DISPLAY TO CHECK THE OUTPUT OF THE ACCESSORY POWER CONVERTER.
Turn the disconnect switch and the key start switch to the ON position.
Start the engine.
Use the Message Display to check the Accessory Bus Voltage.
Note the voltage.
Use the Message Display to check the Water Pump Controller Bus Voltage.
Note the voltage.Expected Result:The voltage measurements are within 10 VDC of each other.Note: The correct operating voltage measurement should be approximately 340 10 VDC.Results:
YES - The voltage measurements are 340 10 VDC. The compressor for the air conditioner is incorrectly reading the voltage measurement.Repair: Replace the compressor. Ensure that the new compressor has corrected the diagnostic code.STOP
NO - One or both of the voltage measurements are higher than expected. The compressor for the air conditioner has responded correctly. The APC may have failed.Repair: Exit this procedure and perform this procedure again. For more information, contact your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time.STOPTest Step 2. CHECK THE CONNECTIONS.Note: Do not perform any maintenance on the Electric Drive System for the Power Train or the Accessory Power System when the Hazardous Voltage System Energized Indicator is illuminated.Note: In order to verify that voltages are at a safe level before machine service is performed, follow the "Safe Shutdown Procedure For Electric Drive Tractors" that is in the Troubleshooting, "Electrical Maintenance Guidelines" section of this manual. Note: After completing the safe shutdown procedure, inspect the harness connectors that are involved in the Hazardous Voltage System Energized Indicator circuits. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure and in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.
Turn the disconnect switch and the key start switch to the OFF position.
Inspect the harness connectors. Clean the contacts of the harness connectors and check the wires for damage to the insulation that is caused by excessive heat, pinching, or chafing.
Reconnect all harness connectors in order to make sure that the connectors are fully seated.
Turn the disconnect switch and the key start switch to the ON position.
Start the engine.
Inspect the cable for damage.
Check the status of the diagnostic code.Expected Result:The diagnostic code is no longer present.Results:
YES - The wiring