C4.4 Marine Generator Set Caterpillar

Oil Filter Differential Pressure Problem

Usage:

C4.4 NRP

Note: This procedure is only applicable to units that have an oil filter inlet pressure sensor.

Use this procedure in order to troubleshoot abnormal oil filter differential pressure or use this procedure if the following event code is active.

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Table 1
Diagnostic Codes for High Oil Filter Differential Pressure
J1939 Codes	Code Description	Comments
6321-15	Engine Oil Filter Differential Pressure : High - least severe (1)	The difference between the filtered oil pressure and the unfiltered oil pressure is greater than the trip point pressure. The code is logged.
6321-16	Engine Oil Filter Differential Pressure : High - moderate severity (2)

Probable Causes

Diagnostic codes
Fuel filter element
Sensor

Recommended Actions

Note: The procedures have been listed in order of probability. Complete the procedures in the order of the listed test steps.

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Table 2
Troubleshooting Test Step	Value	Result
1. Diagnostic Codes A. Connect the electronic service tool to the diagnostic connector. Refer to Troubleshooting, "Electronic Service Tools". B. Check for 6321-X diagnostic codes. D. Check for active diagnostic codes that are associated with the oil filter pressure sensors.	6321-15 6321-16	Result: An associated code is present. Repair: Troubleshoot any associated codes before continuing with this test. Result: A 6321-X code is present. Proceed to the Test Step 2. Result: There are no active diagnostic codes. Return the unit to service.
2. Oil Filter A. Replace the active engine oil filter. Refer to the Operation and Maintenance Manual, "Engine Oil and Filter - Change".	Oil filter	Result: After starting the engine, the 6321-X code is no longer active for the filter that was changed. Return the unit to service. Result: After starting the engine, the 6321-X code is still active for the filters that were changed. Proceed to Test Step 3.
3. Oil Pressure Sensors A. Use the electronic service tool to compare the status of the following parameters with the engine not running: - Pre-filter Oil Pressure - Post-filter Oil Pressure	Oil pressure sensors	Result: A sensor does not read atmospheric pressure while the engine is off. Troubleshoot the sensor circuit. Refer to Troubleshooting, "Sensor Signal (Analog Active) - Test". Result: The sensors read atmospheric pressure while the engine is off. Contact the Technical Communicator at a Cat dealer.