79576A 4 Mercruiser PROPELLER, Aluminum (21 Pitch)

Table 1
Diagnostic Trouble Codes
J1939 Code Description
(code descriptions may vary) Comments
101-15 Engine Crankcase Pressure : High - Least Severe The Engine Control Module (ECM) activates this code when the crankcase pressure has exceeded the limit for a programmed time period. The amber warning lamp is illuminated. The code is logged. Engine power is derated.
This code can be caused by an obstructed tube, an obstructed filter (if equipped), or an obstructed hose. Also, a plugged OCV system will cause the code.
101-16 Engine Crankcase Pressure : High - Moderate Severity The ECM activates this code when the crankcase pressure has exceeded the limit for a programmed time period. The amber warning lamp is illuminated. The code is logged. Engine power is severely derated.
This code can be caused by an obstructed tube, an obstructed filter (if equipped), or an obstructed hose.
Also, a plugged OCV system will cause the code.
Illustration 1 g02211761
(1) Crankcase pressure sensor
(2) Crankcase filter housing (if equipped)
(3) Fumes disposal tube
(4) Oil drain tube
Illustration 2 g02013955
Left side of the engine
(5) Check valve Probable Causes
Engine oil level
Plugged OCV system
Faulty check valve
Faulty sensor
Worn engine componentsRecommended Actions
Table 2
Troubleshooting Test Steps Values Results
1. Check the Engine Oil Level
A. Check the engine oil level.
Engine oil level
Result: The engine oil level is OK.
Proceed to Test Step 2.
Result: The engine oil level is high.
Troubleshoot the cause of the incorrect oil level.
2. Plugged OCV System
A plugged OCV system will cause excessive crankcase pressure.
A. Check the OCV for plugging.
Plugged OCV
Result: The OCV is plugged.
Replace the fumes disposal filter (if equipped) according to the Operation and Maintenance Manual, "Fumes Disposal Filter Element - Replace".
Result: The OCV is not plugged.
Proceed to Test Step 3.
3. Faulty Check Valve
A faulty check valve can cause excessive crankcase pressure. A faulty check valve will not allow the crankcase to vent properly.
A. Replace the check valve.
Check valve
Result: The check valve was replaced.
Verify that the problem is resolved.
If the problem is not resolved, Proceed to Test Step 4.
4. Plugged Oil Disposal Tube
A plugged disposal tube will not allow the crankcase to vent properly.
A. Check the disposal tube for obstructions.
Plugged oil disposal tube
Result The oil disposal tube is obstructed.
Clean any obstructions from the tube.
Result The oil disposal tube is not obstructed.
Proceed to Test Step 5.
5. Faulty Sensor
A. Connect Caterpillar Electronic Technician (ET) to the service tool connector.
B. Turn the keyswitch to the ON position. Do not start the engine.
Remove the oil filler cap.
Monitor the crankcase pressure in Cat ET.
Crankcase pressure sensor
Result The crankcase pressure reading is 0 kpa (0 inches of water) .5 kpa (2 inches of water).
Proceed to Test Step 6.
Result The crankcase pressure reading is not 0 kpa (0 inches of water) .5 kpa (2 inches of water).
Replace the crankcase pressure sensor.
6. Internal Engine Problem
Damaged pistons or rings can cause too much pressure in the crankcase. This condition will cause the engine to run rough. There will be more than the normal quantity of fumes (blowby) entering the OCV system. The OCV system can then more quickly become restricted, causing oil leakage at gaskets and seals that would not normally have leakage. Blowby can also be caused by worn valve guides or by a failed turbocharger seal.
A. To determine whether the piston rings leak, measure the crankcase blowby. Use the following service tools, along with Software License, NETG5044:
1. 285-0900 Blowby Tool Gp (SMALL ENGINE)
2. 348-5430 Multi-Tool Gp
Damaged or worn engine parts
Result There are worn or damaged engine parts.
Repair or replace the worn or damaged parts.
Complete the procedure in the order in which the steps are listed.