C7.1 Engines and Generator Sets Caterpillar

Injector Solenoid - Test

Usage:

C7.1 770

This procedure covers the following diagnostic codes:

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Table 1
Diagnostic Trouble Codes for Injector Solenoid
J1939 Code	CDL Code	Code Description	Comments
651-5	1-5	Engine Injector Cylinder #01 : Current Below Normal	These diagnostic codes indicate an open circuit (low current) in either the solenoid or the wiring for the electronic unit injector. The Electronic Control Module (ECM) detects the following conditions: A low current condition (open circuit) for each of five consecutive attempts to operate Battery voltage above 9 VDC for 2 seconds The warning light will come on. The ECM will log the diagnostic code. The engine will have low power and/or rough running. When an "Cylinder Cutout Test" is performed, a faulty electronic unit injector will indicate a low reading in comparison with the other electronic unit injectors. The ECM will continue to attempt to operate the electronic unit injector after the diagnostic code has been logged. An open circuit will prevent the operation of the electronic unit injector.
652-5	2-5	Engine Injector Cylinder #02 : Current Below Normal
653-5	3-5	Engine Injector Cylinder #03 : Current Below Normal
654-5	4-5	Engine Injector Cylinder #04 : Current Below Normal
655-5	5-5	Engine Injector Cylinder #05 : Current Below Normal
656-5	6-5	Engine Injector Cylinder #06 : Current Below Normal
651-6	1-6	Engine Injector Cylinder #01 : Current Above Normal	These diagnostic codes indicate a short circuit (high current) in either the solenoid or the wiring for the electronic unit injector. The ECM detects the following conditions: A high current condition (short circuit) for each of five consecutive attempts to operate Battery voltage above 9 VDC for 2 seconds The warning light will come on. The ECM will log the diagnostic code. The engine will have low power and/or rough running. The ECM will continue to attempt to operate the electronic unit injector after the diagnostic code has been logged. A short circuit will prevent the operation of the electronic unit injector.
652-6	2-6	Engine Injector Cylinder #02 : Current Above Normal
653-6	3-6	Engine Injector Cylinder #03 : Current Above Normal
654-6	4-6	Engine Injector Cylinder #04 : Current Above Normal
655-6	5-6	Engine Injector Cylinder #05 : Current Above Normal
656-6	6-6	Engine Injector Cylinder #06 : Current Above Normal
Follow the troubleshooting procedure to identify the root cause of the fault.

Perform this procedure under conditions that are identical to the conditions that exist when the fault occurs. Typically, faults with the injector solenoid occur when the engine is warmed up and/or when the engine is under vibration (heavy loads).

These engines have Electronic Unit Injectors (EUI). The ECM sends a pulse to each injector solenoid. The pulse is sent at the correct time and at the correct duration for a given engine load and speed. The solenoid is mounted on top of the fuel injector body.

An electrical fault can prevent the electronic unit injector from operating. An open or short circuit in the ECM that is unique to one electronic unit injector will prevent that electronic unit injector from operating. An open or short circuit in common wiring within the ECM can prevent the two electronic unit injectors that share that common wiring from operating.

If an open circuit is detected in the solenoid circuit, a diagnostic code is generated. The ECM continues to try to fire the injector. If a short circuit is detected, a diagnostic code is generated. The ECM will periodically try to fire the injector. If the short circuit remains, this sequence of events will be repeated until the fault is corrected.

"Injector Solenoid Test"

Use the "Injector Solenoid Test"to diagnose an open or short circuit diagnostic code while the engine is not running. The "Injector Solenoid Test" will send a signal to each solenoid. The electronic service tool will indicate the status of the solenoid as "OK", "Open", or "Short".

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Electrical Shock Hazard. The electronic unit injectors use DC voltage. The ECM sends this voltage to the electronic unit injectors. Do not come in contact with the harness connector for the electronic unit injectors while the engine is operating. Failure to follow this instruction could result in personal injury or death.

During the following procedure, refer to the electrical schematic for the application.

Complete the procedure in the order in which the steps are listed.

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Table 2
Troubleshooting Test Steps	Values	Results
1. Inspect Electrical Connectors and Wiring A. Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned OFF. B. Thoroughly inspect the connectors at the cylinder head. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details. C. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with injector solenoids. D. Check the screw for the ECM connector for the correct torque of 6 N·m (53 lb in). E. Check the harness and wiring for abrasion and for pinch points from the injectors to the ECM.	Loose connection or damaged wire	Result: There is a fault in a connector or the wiring. Repair: Repair any faulty connectors or replace the wiring harness. Ensure that all the seals are properly in place and ensure that the connectors are correctly coupled. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: All connectors, pins, and sockets are correctly coupled and/or inserted. The harness is free of corrosion, abrasion, and pinch points. Proceed to Test Step 2.
2. Use the "Injector Solenoid Test" A. Start the engine. B. Allow the engine to warm to the normal operating temperature. C. Stop the engine. D. Turn the keyswitch to the ON position. E. Access the "Injector Solenoid Test" by accessing the following display screens in order: · "Diagnostics" · "Diagnostic Tests" · "Injector Solenoid Test" F. Activate the test. Note: Do not confuse the "Injector Solenoid Test" with the "Cylinder Cutout Test". The "Cylinder Cutout Test" is used to shut off fuel to a specific cylinder while the engine is running. The "Injector Solenoid Test" is used to actuate the injector solenoids while the engine is not running.	"OK", "OPEN", or "SHORT"	Result: All cylinders indicate "OK". There is not an electronic fault with the injectors. Use the electronic service tool to clear all logged diagnostic codes. Return the engine to service. Result: "OPEN" Note the cylinders that indicate "OPEN". Proceed to Test Step 3. Result: "SHORT" Note the cylinders that indicate "SHORT". Proceed to Test Step 4.
3. Check the Harness between the ECM and the Cylinder Head for an Open Circuit A. Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned OFF. B. Disconnect the connector for the suspect injector from the cylinder head. C. Fabricate a jumper wire 100 mm (4 inch) long with terminals on both ends of the wire. D. Insert one end of the jumper wire into the terminal for the supply to the suspect injector. Insert the other end of the jumper wire into the terminal for the return circuit for the suspect injector. E. Turn the keyswitch to the ON position. F. Perform the "Injector Solenoid Test" at least two times. G. Repeat this test for each suspect injector. Stop the "Injector Solenoid Test" before handling the jumper wires.	Suspect injector indicates "SHORT"	Result: The electronic service tool displays "SHORT" for the cylinder with the jumper wire. Proceed to Test Step 5. Result: The electronic service tool does not display "SHORT" for the cylinder with the jumper wire. Proceed to Test Step 6.
4. Check the Harness between the ECM and the Cylinder Head for a Short Circuit A. Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned OFF. B. Disconnect the connector for the suspect injector from the cylinder head. C. Turn the keyswitch to the ON position. D. Perform the "Injector Solenoid Test" at least two times. E. Repeat this test for each suspect injector. Stop the "Injector Solenoid Test" before handling the jumper wires.	Suspect injector indicates "OPEN"	Result: The electronic service tool displays "OPEN" for the suspect cylinder and the other cylinder that shares the same connector. Proceed to Test Step 5. Result: The electronic service tool does not display "OPEN" for the suspect cylinder. Proceed to Test Step 6.
5. Exchange the Injector Harness Under the Valve Mechanism Cover A. Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned OFF. B. Remove the valve mechanism cover. Refer to Disassembly and Assembly, "Valve Mechanism Cover - Remove and Install" for the correct procedure. C. Disconnect the connector for the suspect injector from the cylinder head. Disconnect the connector from the adjacent pair of injectors. D. Exchange the two internal harnesses. Refer to Disassembly and Assembly, "Electronic Unit Injector - Remove" and refer to Disassembly and Assembly, "Electronic Unit Injector - Install" for the correct procedure. E. Turn the keyswitch to the ON position. F. Perform the "Injector Solenoid Test" at least two times. G. Restore the wiring to the normal positions.	Fault moves to another injector	Result: Exchanging the harnesses causes the fault to move to another injector. There is a fault with the suspect injector harness under the valve mechanism cover. Repair: Repair the suspect injector harness or replace the suspect injector harness under the valve mechanism cover. Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair eliminates the fault. Result: The fault remains on the same injector when the harness is exchanged. The injector may be faulty. Repair: Replace the faulty injector. Refer to Disassembly and Assembly, "Electronic Unit Injector - Remove" and Disassembly and Assembly, "Electronic Unit Injector - Install". Perform the "Injector Solenoid Test". Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
6. Check the Wiring to the Cylinder Head for an Open Circuit A. Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned OFF. B. Disconnect connector P2 from the ECM. C. Thoroughly inspect the P2 connector. Refer to Troubleshooting, "Electrical Connectors - Inspect". D. Disconnect the connector for the suspect injector from the cylinder head. E. Use a multimeter to check the resistance between the terminals on the suspect cylinder head connector and the terminals on P2. F. Install the removed connectors.	Less than 2.0 Ohms	Result: One or more of the measured resistances is greater than 2.0 Ohms. The fault is in the wiring between the ECM and the cylinder head connector. Repair: Repair the faulty wiring or replace the faulty wiring. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: The measured resistances for the suspect injector wiring are less than 2.0 Ohms. Proceed to Test Step 7.
7. Check the Wiring to the Cylinder Head for a Short Circuit A. Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned OFF. B. Disconnect connector P2 from the ECM. C. Thoroughly inspect the P2 connector. Refer to Troubleshooting, "Electrical Connectors - Inspect". D. Disconnect the connector for the suspect injector from the cylinder head. E. Check the resistance between the terminals for the suspect injector on P2 and all other terminals on P2. F. Install the removed connectors.	Greater than 100 Ohms	Result: At least one of the resistance measurements is less than 100 Ohms. There is a short in the wiring between the relay and the ECM. Repair: Repair the faulty wiring or replace the faulty wiring. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: All resistance measurements are greater than 100 Ohms. Contact the Dealer Solutions Network (DSN).