3512B and 3512C Petroleum Generator Set Engines Caterpillar

Use this procedure to troubleshoot the injector solenoid circuit if a problem is suspected with the injectors. Also, use this procedure if any of the diagnostic codes in Table 1 is active or easily repeated.

Table 1

Diagnostic Codes Table
J1939 Code and Description	Conditions which Generate this Code	System Response
651-5 Engine Injector Cylinder #01 : Current Below Normal	The Electronic Control module (ECM) detects a low current in the circuit for the injector solenoid.	The code is logged. The ECM continues the attempt to energize the solenoid circuit until the circuit is repaired.
651-6 Engine Injector Cylinder #01 : Current Above Normal	The ECM detects a high current in the circuit for the injector solenoid.	The code is logged. The ECM disables this solenoid circuit. The ECM will periodically attempt to energize the solenoid circuit until the circuit is repaired.
652-5 Engine Injector Cylinder #02 : Current Below Normal	The ECM detects a low current in the circuit for the injector solenoid.	The code is logged. The ECM continues the attempt to energize the solenoid circuit until the circuit is repaired.
652-6 Engine Injector Cylinder #02 : Current Above Normal	The ECM detects a high current in the circuit for the injector solenoid.	The code is logged. The ECM disables this solenoid circuit. The ECM will periodically attempt to energize the solenoid circuit until the circuit is repaired.
653-5 Engine Injector Cylinder #03 : Current Below Normal	The ECM detects a low current in the circuit for the injector solenoid.	The code is logged. The ECM continues the attempt to energize the solenoid circuit until the circuit is repaired.
653-6 Engine Injector Cylinder #03 : Current Above Normal	The ECM detects a high current in the circuit for the injector solenoid.	The code is logged. The ECM disables this solenoid circuit. The ECM will periodically attempt to energize the solenoid circuit until the circuit is repaired.
654-5 Engine Injector Cylinder #04 : Current Below Normal	The ECM detects a low current in the circuit for the injector solenoid.	The code is logged. The ECM continues the attempt to energize the solenoid circuit until the circuit is repaired.
654-6 Engine Injector Cylinder #04 : Current Above Normal	The ECM detects a high current in the circuit for the injector solenoid.	The code is logged. The ECM disables this solenoid circuit. The ECM will periodically attempt to energize the solenoid circuit until the circuit is repaired.
655-5 Engine Injector Cylinder #05 : Current Below Normal	The ECM detects a low current in the circuit for the injector solenoid.	The code is logged. The ECM continues the attempt to energize the solenoid circuit until the circuit is repaired.
655-6 Engine Injector Cylinder #05 : Current Above Normal	The ECM detects a high current in the circuit for the injector solenoid.	The code is logged. The ECM disables this solenoid circuit. The ECM will periodically attempt to energize the solenoid circuit until the circuit is repaired.
656-5 Engine Injector Cylinder #06 : Current Below Normal	The ECM detects a low current in the circuit for the injector solenoid.	The code is logged. The ECM continues the attempt to energize the solenoid circuit until the circuit is repaired.
656-6 Engine Injector Cylinder #06 : Current Above Normal	The ECM detects a high current in the circuit for the injector solenoid.	The code is logged. The ECM disables this solenoid circuit. The ECM will periodically attempt to energize the solenoid circuit until the circuit is repaired.
657-5 Engine Injector Cylinder #07 : Current Below Normal	The ECM detects a low current in the circuit for the injector solenoid.	The code is logged. The ECM continues the attempt to energize the solenoid circuit until the circuit is repaired.
657-6 Engine Injector Cylinder #07 : Current Above Normal	The ECM detects a high current in the circuit for the injector solenoid.	The code is logged. The ECM disables this solenoid circuit. The ECM will periodically attempt to energize the solenoid circuit until the circuit is repaired.
658-5 Engine Injector Cylinder #08 : Current Below Normal	The ECM detects a low current in the circuit for the injector solenoid.	The code is logged. The ECM continues the attempt to energize the solenoid circuit until the circuit is repaired.
658-6 Engine Injector Cylinder #08 : Current Above Normal	The ECM detects a high current in the circuit for the injector solenoid.	The code is logged. The ECM disables this solenoid circuit. The ECM will periodically attempt to energize the solenoid circuit until the circuit is repaired.
659-5 Engine Injector Cylinder #09 : Current Below Normal	The ECM detects a low current in the circuit for the injector solenoid.	The code is logged. The ECM continues the attempt to energize the solenoid circuit until the circuit is repaired.
659-6 Engine Injector Cylinder #09 : Current Above Normal	The ECM detects a high current in the circuit for the injector solenoid.	The code is logged. The ECM disables this solenoid circuit. The ECM will periodically attempt to energize the solenoid circuit until the circuit is repaired.
660-5 Engine Injector Cylinder #10 : Current Below Normal	The ECM detects a low current in the circuit for the injector solenoid.	The code is logged. The ECM continues the attempt to energize the solenoid circuit until the circuit is repaired.
660-6 Engine Injector Cylinder #10 : Current Above Normal	The ECM detects a high current in the circuit for the injector solenoid.	The code is logged. The ECM disables this solenoid circuit. The ECM will periodically attempt to energize the solenoid circuit until the circuit is repaired.
661-5 Engine Injector Cylinder #11 : Current Below Normal	The ECM detects a low current in the circuit for the injector solenoid.	The code is logged. The ECM continues the attempt to energize the solenoid circuit until the circuit is repaired.
661-6 Engine Injector Cylinder #11 : Current Above Normal	The ECM detects a high current in the circuit for the injector solenoid.	The code is logged. The ECM disables this solenoid circuit. The ECM will periodically attempt to energize the solenoid circuit until the circuit is repaired.
662-5 Engine Injector Cylinder #12 : Current Below Normal	The ECM detects a low current in the circuit for the injector solenoid.	The code is logged. The ECM continues the attempt to energize the solenoid circuit until the circuit is repaired.
662-6 Engine Injector Cylinder #12 : Current Above Normal	The ECM detects a high current in the circuit for the injector solenoid.	The code is logged. The ECM disables this solenoid circuit. The ECM will periodically attempt to energize the solenoid circuit until the circuit is repaired.

Background Information

Perform this procedure during operating conditions that are identical to the operating conditions that exist when the problem occurs. Typically, problems with the injector solenoid occur when the engine is warmed up and/or when the engine is under vibration (heavy loads). The wiring and/or the connectors may have problems that only occur during vibration.

These engines have fuel injectors that are electronically controlled. A solenoid is used to actuate the injector. The solenoid is mounted on top of the fuel injector body. The ECM sends a 105 V pulse to the injector solenoid. The pulse is sent at the proper time and for the correct duration for any given engine load and speed.

Trim Files

When an injector is replaced, program the new injector code into the Electronic Control Module (ECM). Refer to Troubleshooting, "Injector Trim File - Install" for information that is related to trim files. If the ECM is replaced, all of the injector codes must be programmed into the new ECM. Refer to Troubleshooting, "Injector Trim File - Install" for information that is related to the configuration of a new ECM.

Diagnostic Tests that are Available on Caterpillar Electronic Technician (ET)

Cat ET includes the following tests that will aid in troubleshooting injector solenoids:

Note: Dual data link communications must be established between the service tool and the engine ECM prior to gaining access to some of the following tests. For information on dual data link communications, refer to Troubleshooting, "Electronic Service Tools" for details.

Cylinder Cutout Test - The "Cylinder Cutout Test" is used on an engine in order to determine the individual cylinder performance while the engine is running. As one or more cylinders are cut out during the test, the "Cylinder Cutout Test" uses "Fuel Position" to evaluate the performance of the cylinders. As different cylinders are cut out, a comparison of the change in fuel injection delivery is used to identify cylinders that are weak or misfiring. When a malfunctioning injector is cut out, the increase in fuel delivery is less than the increase for a cylinder that is performing normally. One reason for a cylinder that is weak or misfiring is an injector that is malfunctioning.

Injector Solenoid Test - This test identifies an open circuit or a short circuit in the circuits for the injector solenoids. The test is performed while the engine is not running. The "Injector Solenoid Test" briefly activates each solenoid. A good solenoid will create an audible click when the solenoid is activated. Cat ET indicates the status of the solenoid as "OK", "Open", or "Short".

Illustration 1	g03317453
Injector schematic

Illustration 2	g03318080
Engine schematic color legend

Illustration 3	g03317985
Terminal locations of the injector solenoids at the P2/J2 connector. (P2-1) Injector 1 supply (P2-2) Injector 1 return (P2-3) Injector 2 supply (P2-4) Injector 2 return (P2-14) Injector 5 supply (P2-15) Injector 5 return (P2-16) Injector 6 supply (P2-17) Injector 6 return (P2-24) Injector 9 supply (P2-25) Injector 9 return (P2-34) Injector 10 supply (P2-35) Injector 10 return (P2-40) Injector 3 supply (P2-41) Injector 3 return (P2-42) Injector 4 supply (P2-43) Injector 4 return (P2-48) Injector 7 supply (P2-49) Injector 7 return (P2-50) Injector 8 supply (P2-51) Injector 8 return (P2-52) Injector 12 supply (P2-58) Injector 11 supply (P2-59) Injector 11 return (P2-62) Injector 12 return

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Electrical Shock Hazard. The unit injector system uses 90 - 120 volts. The ECM sends this signal to the unit injectors. Do not come in contact with the unit injector harness connector while the engine is operating. Failure to follow this instruction could resulting in personal injury or death.

Table 2

Troubleshooting Test Steps	Values	Results
1. Check for Logged Codes or Active Codes A. Establish communication between Cat ET and the engine ECM. Refer to Troubleshooting, "Electronic Service Tools", if necessary. B. Determine if the -5 or -6 code is active or logged.	Codes	Results: A -5 code or a -6 code is logged or active. Proceed to Test Step 3. Result: A code is not logged or active. Proceed to Test Step 2.
2. Perform the "Cylinder Cutout Test" A. Start the engine. Allow the engine to warm up to normal operating temperature . B. Perform the "Cylinder Cutout Test". Check for a noticeable change in fuel usage.	Fuel usage	Results: There is a noticeable change in fuel usage. The injectors are firing on all cylinders at this time. Proceed to Test Step 3. Results: There is not a noticeable change in fuel usage. Verify that the valve lash for the suspect cylinder is OK then replace the suspect injector. Verify that the repair eliminated the problem.
3. Check the Harness between the ECM and the Injector Connectors for an Open Circuit A. A. Turn the main disconnect switch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned off. B. Disconnect the harness connectors for the affected cylinder at the cylinder head. C. Fabricate a jumper wire that is long enough to create a test circuit across the harness connector at the cylinder head. Crimp connector pins to each end of the jumper wire. D. Connect the jumper wire between terminal locations 1 (supply) and 2 (return). This test will effectively create a short circuit for the cylinder. E. Restore the electrical power to the ECM. F. Perform the "Injector Solenoid Test" at least two times.	Harness	Results: Cat ET displays "Short" for the cylinder with the jumper wire. The harness is OK. Remove the jumper wire. Connect the harness connectors. Proceed to Test Step 4. Results: Cat ET displays "Open" for the cylinder with the jumper wire. The ECM did not detect the jumper wire. There is an open circuit in the wiring harness. Repair Correct the problem with the harness. Replace parts, if necessary. Start the engine. Verify that the repair eliminated the problem.
4. Check the Harness between the ECM and the Injector Connectors for a Short Circuit A. Turn the main disconnect switch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned off. B. Disconnect the harness connectors for the injector solenoid at the cylinder head. There will then be an open circuit at the harness connector. C. Restore the electrical power to the ECM. D. Perform the "Injector Solenoid Test" at least two times.	Harness	Results: The suspect cylinder indicates "Open" on Cat ET. The harness is OK. Connect the harness connectors. Proceed to Test Step 5. Results: A cylinder indicates "Short" on Cat ET. There is a problem with the harness. Repair Correct the problem with the harness. Replace parts, if necessary. Start the engine. Verify that the repair eliminated the problem.
5. Check the Harness between the ECM and the Rigid Harness for a Short Circuit A. Turn the main disconnect switch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned off. B. Disconnect the harness connectors for the injector solenoid at the cylinder head. There will then be an open circuit at the harness connector. C. Restore the electrical power to the ECM. D. Perform the "Injector Solenoid Test" at least two times.	Harness	Results: The suspect cylinder indicates "Open" on Cat ET. The harness is OK. Connect the harness connectors. Proceed to Test Step 6. Results: A cylinder indicates "Short" on Cat ET. There is a problem with the harness. Repair Correct the problem with the harness. Replace parts, if necessary. Start the engine. Verify that the repair eliminated the problem.
6. Check the Harness between the ECM and the Rigid Harness for an Open Circuit A. Turn the main disconnect switch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned off. B. Disconnect the harness connectors for the affected cylinder at the cylinder head. C. Fabricate a jumper wire that is long enough to create a test circuit across the harness connector at the cylinder head. Crimp connector pins to each end of the jumper wire. D. Connect the jumper wire between terminal locations 1 (supply) and 2 (return). This test will effectively create a short circuit for the cylinder. E. Restore the electrical power to the ECM. F. Perform the "Injector Solenoid Test" at least two times.	Harness	Results: Cat ET displays "Short" for the cylinder with the jumper wire. The harness is OK. Remove the jumper wire. Connect the harness connectors. Proceed to Test Step 7. Results: Cat ET displays "Open" for the cylinder with the jumper wire. The ECM did not detect the jumper wire. There is an open circuit in the wiring harness. Repair Correct the problem with the harness. Replace parts, if necessary. Start the engine. Verify that the repair eliminated the problem.
7. Check the ECM for Proper Operation A. Turn the main disconnect switch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned off. B. Disconnect the P2 connector. When the P2 connector is disconnected, numerous diagnostic codes will be generated when the keyswitch is turned ON. The codes are normal. Ignore the codes. Reset all active codes and clear all logged codes after you complete this Test Step. C. Restore the electrical power to the ECM. D. Activate the "Injector Solenoid Test". Allow the Injector Solenoid Test to continue until each solenoid is activated at least two times. E. Turn the main disconnect switch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned off. F. Use a jumper wire in order to create a short circuit on J2 between the terminals for the solenoids supply and the solenoids return. G. Restore the electrical power to the ECM. H. Activate the Injector Solenoid Test. Allow the Injector Solenoid Test to continue until each solenoid is activated at least two times.	ECM	Result: Cat ET displays "Short" for the solenoid with the jumper wire. Cat ET will display "Open" when the P2 connector is not connected to the ECM. The problem is in the injector. Replace the injector and perform an injector solenoid test. Verify that the repair eliminated the problem. Result: Cat ET does not display "Short" for the solenoid with the jumper wire. Cat ET does not display "Open" when P2 is not connected to the ECM. Perform the following procedure: 1. Temporarily connect a test ECM. Refer to Troubleshooting, "Test ECM Mode". 2. Activate the "Injector Solenoid Test". Allow the Injector Solenoid Test to continue until each solenoid is activated at least two times. If the test ECM fixes the problem, connect the suspect ECM. If the problem returns with the suspect ECM, replace the ECM. Note: Before you consider replacing the ECM, consult with the Dealer Solutions Network (DSN) for assistance. Verify that the repair eliminated the problem.