3512C Engines for 785C Off-Highway Trucks with Dynamic Gas Blending Caterpillar

In Cylinder Pressure Is Low

Usage:

3512 8BR

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

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Table 1
J1939 Code and Description	CDL Code and Description	Comments
6483-18 Engine Cylinder #1 Indicated Mean Effective Pressure : Low - moderate severity (2)	E1747 (2) Low Engine Cylinder #1 Indicated Mean Effective Pressure	The In Cylinder Pressure Sensor (ICPS) has measured cylinder pressure is less than the expected value. The code is logged.
6487-18 Engine Cylinder #2 Indicated Mean Effective Pressure : Low - moderate severity (2)	E1748 (2) Low Engine Cylinder #2 Indicated Mean Effective Pressure	The ICPS has measured cylinder pressure is less than the expected value. The code is logged.
6491-18 Engine Cylinder #3 Indicated Mean Effective Pressure : Low - moderate severity (2)	E1749 (2) Low Engine Cylinder #3 Indicated Mean Effective Pressure	The ICPS has measured cylinder pressure is less than the expected value. The code is logged.
6495-18 Engine Cylinder #4 Indicated Mean Effective Pressure : Low - moderate severity (2)	E1750 (2) Low Engine Cylinder #4 Indicated Mean Effective Pressure	The ICPS has measured cylinder pressure is less than the expected value. The code is logged.
6499-18 Engine Cylinder #5 Indicated Mean Effective Pressure : Low - moderate severity (2)	E1751 (2) Low Engine Cylinder #5 Indicated Mean Effective Pressure	The ICPS has measured cylinder pressure is less than the expected value. The code is logged.
6503-18 Engine Cylinder #6 Indicated Mean Effective Pressure : Low - moderate severity (2)	E1752 (2) Low Engine Cylinder #6 Indicated Mean Effective Pressure	The ICPS has measured cylinder pressure is less than the expected value. The code is logged.
6507-18 Engine Cylinder #7 Indicated Mean Effective Pressure : Low - moderate severity (2)	E1753 (2) Low Engine Cylinder #7 Indicated Mean Effective Pressure	The ICPS has measured cylinder pressure is less than the expected value. The code is logged.
6511-18 Engine Cylinder #8 Indicated Mean Effective Pressure : Low - moderate severity (2)	E1754 (2) Low Engine Cylinder #8 Indicated Mean Effective Pressure	The ICPS has measured cylinder pressure is less than the expected value. The code is logged.
6515-18 Engine Cylinder #9 Indicated Mean Effective Pressure : Low - moderate severity (2)	E1755 (2) Low Engine Cylinder #9 Indicated Mean Effective Pressure	The ICPS has measured cylinder pressure is less than the expected value. The code is logged.
6519-18 Engine Cylinder #10 Indicated Mean Effective Pressure : Low - moderate severity (2)	E1756 (2) Low Engine Cylinder #10 Indicated Mean Effective Pressure	The ICPS has measured cylinder pressure is less than the expected value. The code is logged.
6523-18 Engine Cylinder #11 Indicated Mean Effective Pressure : Low - moderate severity (2)	E1757 (2) Low Engine Cylinder #11 Indicated Mean Effective Pressure	The ICPS has measured cylinder pressure is less than the expected value. The code is logged.
6527-18 Engine Cylinder #12 Indicated Mean Effective Pressure : Low - moderate severity (2)	E1758 (2) Low Engine Cylinder #12 Indicated Mean Effective Pressure	The ICPS has measured cylinder pressure is less than the expected value. The code is logged.

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Table 2
Associated Codes
J1939 Code	CDL Code	Troubleshooting Procedure
95-0	E390 (3)	Troubleshooting, "Fuel Filter Is Restricted"
95-15	E390 (1)	Troubleshooting, "Fuel Filter Is Restricted"
95-16	E390 (2)	Troubleshooting, "Fuel Filter Is Restricted"
107-15	E583 (1)	Troubleshooting, "Inlet Air Is Restricted"
107-16	E583 (2)	Troubleshooting, "Inlet Air Is Restricted"
651-5 to 662-5	1-5 to 12-5	Troubleshooting, "Injector Solenoid - Test"
651-6 to 662-6	1-6 to 12-6	Troubleshooting, "Injector Solenoid - Test"
2809-15	E584 (1)	Troubleshooting, "Inlet Air Is Restricted"
2809-16	E584 (2)	Troubleshooting, "Inlet Air Is Restricted"
3509-3	262-3	Troubleshooting, "Sensor Supply - Test"
3509-4	262-4	Troubleshooting, "Sensor Supply - Test"
5580-17	E198 (1)	Troubleshooting, "Fuel Pressure Is Low"
5580-18	E198 (2)	Troubleshooting, "Fuel Pressure Is Low"
6161-3 to 6172-3	4805-3 to 4816-3	Troubleshooting, "Sensor Signal (Analog, Active) - Test (In Cylinder Pressure Sensor)"
6161-4 to 6172-4	4805-4 to 4816-4	Troubleshooting, "Sensor Signal (Analog, Active) - Test (In Cylinder Pressure Sensor)"
6161-13 to 6172-13	4805-13 to 4816-13	Troubleshooting, "Sensor Calibration Required - Test (In Cylinder Pressure Sensor)"
6161-20 to 6172-20	4805-20 to 4816-20	Troubleshooting, "Sensor Signal (Analog, Active) - Test (In Cylinder Pressure Sensor)"
6161-21 to 6172-21	4805-21 to 4816-21	Troubleshooting, "Sensor Signal (Analog, Active) - Test (In Cylinder Pressure Sensor)"
6466-17	E221 (1)	Troubleshooting, "Fuel Pressure Is Low (Gas Supply)"

Probable Causes

Codes
Fuel injectors
Sensor
Cylinder head bore
Valve train

Recommended Actions

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Table 3
Troubleshooting Test Steps	Values	Results
1. Check for Codes A. Connect Cat^® Electronic Technician (ET) to the service tool connector. B. Look for active codes that are associated with the system for the event code.	Codes	Result: An associated code is active. Repair: Troubleshoot any associated codes before continuing with this test. Result: A code is active or logged. Proceed to Test Step 2.
2. Test the Fuel Injectors A. Connect Cat ET. B. Use Cat ET to perform the following fuel injector tests: - "Injector Solenoid Test" - "Cylinder Cutout Test" - "Solenoid Valve -Test (Gas Admission Valve)" Refer to Troubleshooting, "Cat ET Service Features" for additional information.	Fuel Injectors	Result: The tests were successful. Proceed to Test Step 3. Result: The tests were not successful. Repair: Diagnose the problem. Repair or replace damaged components. If the problem is not resolved, proceed to Test Step 3.
3. Check the Torque of the In Cylinder Pressure Sensor (ICPS) Sensor A. Turn the keyswitch to the OFF position. B. Disconnect the ICPS adapter harness from the pressure sensor. C. Check the ICPS torque value. Note: Low sensor torque may allow leakage and lower than expected cylinder pressures.	Torque	Result: The sensor was torqued to 11.5 ± 1 N·m (102 ± 9 lb in). Proceed to Test Step 4. Result: The sensor was not torqued to 11.5 ± 1 N·m (102 ± 9 lb in). Repair: Torque the sensor to 11.5 ± 1 N·m (102 ± 9 lb in). Run the engine to high idle and look for the active code to return. If the problem is not resolved, proceed to Test Step 4.
4. Check ICPS Cylinder Head Bore A. Turn the keyswitch to the OFF position. B. Disconnect the ICPS adapter harness from the pressure sensor. C. Remove ICPS from the cylinder head. D. Inspect and clean ICPS bore and sensor seat for debris. E. Reinstall the ICPS and torque to 11.5 ± 1 N·m (102 ± 9 lb in). F. Reconnect the ICPS adapter harness. G. Start the engine. Run the engine at high idle H. Connect Cat ET. J. Use Cat ET to look for the following: - Codes	Cylinder Head Bore	Result: After inspection, cleaning, and proper sensor installation, the code remained active. Proceed to Test Step 5. Result: After inspection, cleaning, and proper sensor installation, the code is not active. Return to service.
5. Swap ICPS with another Known Good ICPS A. Turn the keyswitch to the OFF position. B. Disconnect the ICPS adapter harness from the pressure sensor. Note: Use caution removing and installing ICPS not to introduce debris into the good sensor. C. Remove ICPS from the cylinder head. D. Swap the affected ICPS with a known good ICPS. E. Reconnect the ICPS adapter harness to the pressure sensor.	Sensor	Result: A code remained active with a known good sensor installed. Proceed to Test Step 6. Result: A code is not active on the cylinder that had the original code with a known good sensor installed. Repair: Replace the ICPS. If the problem is not resolved, proceed to Test Step 6.
6. Inspect the Valve Train Components A. Remove the valve mechanism cover and the camshaft covers. B. Check the valve lash. Refer to Testing and Adjusting, "Valve Lash - Adjust" for additional information. C. Check the following valve train components for damage: - Camshaft - Valve rotocoil - Valve springs - Camshaft followers - Rocker shaft - Bridges - Pushrods - Injectors D. Check for valves that do not move freely. Remove the cylinder head and inspect the valves. Refer to the Disassembly and Assembly manual for additional information.	Valve Train	Result: The valve train components are not damaged. Proceed to Test Step 7. Result: The valve train components are damaged. Repair: Repair or replace damaged valve train components. If the problem is not resolved, proceed to Test Step 7.
7. Perform a Cylinder Leak Test A. Refer to Special Instruction, REHS7138 for additional information.	Test	Result: The cylinder leak down rate indicates that there is a problem with the piston, piston rings, or cylinder liner. Repair: Repair or replace damaged 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).