G3500H Generator Set Engine Caterpillar

Crankcase Pressure Is High

Usage:

Use this procedure to troubleshoot a high crankcase pressure. Also, use this procedure if one of the following event codes is active or logged.

Show/hide table

Table 1
J1939 Code and Description	Comments
101-0 Engine Crankcase Pressure : High - most severe (3)	The engine crankcase pressure is greater than the trip point pressure for the programmed delay time. The code is logged.
101-15 Engine Crankcase Pressure : High - least severe (1)	The engine crankcase pressure is greater than the trip point pressure for the programmed delay time. The code is logged.

Note: The crankcase pressure sensor is only available for the G3512H engine application.

Probable Causes

Oil level
Crankcase breather
Ventilation system (if equipped)
Sensor
Worn engine components

Recommended Actions

Show/hide table

Table 2
Troubleshooting Test Steps	Values	Results
1. Check the Engine Oil Level	Oil Level	Result: The engine oil level is OK. Proceed to Test Step 2. Result: The engine oil level is high. Repair: Troubleshoot the cause of the incorrect oil level. If the problem is not resolved, proceed to Test Step 2.
2. Check for a Plugged Crankcase Breather Note: If the engine is running in cold ambient temperatures, check to ensure that the breather tube is not plugged with ice.	Plugged Breather	Result: The crankcase breather is not plugged. Proceed to Test Step 3. Result: The crankcase breather is plugged. Repair: Replace the crankcase breather. Note: A plugged crankcase breather can cause the crankshaft seal to leak. Sealing of the piston rings can be lost and the increase in crankcase blowby will increase the crankcase pressure. If the problem is not resolved, proceed to Test Step 3.
3. Check the Crankcase Ventilation System Note: Engines that use bio-gas may have a system for ventilation of the crankcase. A problem with the ventilation system can increase the crankcase pressure.	Ventilation System	Result: The crankcase ventilation system is OK. Proceed to Test Step 4. Result: The crankcase ventilation system is NOT OK. Repair: For information on crankcase ventilation system, refer to the Original Equipment Manufacturers (OEM) service information. If the problem is not resolved, proceed to Test Step 4.
4. Check the Crankcase Pressure Sensor A. Connect Cat^® Electronic Technician (ET) to the service tool connector. B. Turn the main disconnect switch to the ON position. Do not start the engine. C. Remove the oil filler cap. D. Use Cat ET to monitor the following pressures: - Crankcase pressure	Sensor	Result: The crankcase pressure is within 0 ± 1 kPa (0 ± 4inch of H₂O) of 0 with the main disconnect switch in the ON position. Proceed to Test Step 6. Result: The crankcase pressure is not within 0 ± 1 kPa (0 ± 4inch of H₂O) of 0 with the main disconnect switch in the ON position. Proceed to Test Step 5.
5. Inspect the Electrical Connectors and the Wiring A. Turn the main disconnect switch to the OFF position. B. Thoroughly inspect the connectors. Refer to Troubleshooting, "Electrical Connectors-Inspect" for additional information. C. Perform a 45 N (10 lb) pull test on the connector wires. D. Check the harness for abrasions and pinch points.	Connectors and Wiring	Result: The connectors and wiring appear to be OK. Repair: Replace the sensor. If the problem is not resolved, proceed to Test Step 6. Result: There is a problem with the connectors and/or wiring. Repair: Repair or replace the connectors or wiring. Ensure that all the seals are properly in place and ensure that the connectors are coupled. If the problem is not resolved, proceed to Test Step 6.
6. Inspect the Engine for Internal Problems Note: Damaged pistons or rings can cause too much pressure in the crankcase. This condition will cause the engine to run rough.	Damaged or Worn Engine Components	Result: There are worn or damaged engine components. Repair: Repair or replace the worn or damaged engine components. 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).