3512 and 3516 EUI Engines for 784B, 785B, 789B and 793B Off-Highway Trucks Engine Overspeed Lamp and Engine Overspeed Alarm Caterpillar


Engine Overspeed Lamp and Engine Overspeed Alarm
`
3512 and 3516 EUI Engines for 784B, 785B, 789B and 793B Off-Highway Trucks [SENR5597]
ELECTRICAL AND STARTING SYSTEM
ALARM GP
3512 and 3516 EUI Engines for 784B, 785B, 789B and 793B Off-Highway Trucks Engine Overspeed Lamp and Engine Overspeed Alarm

System Operation Description:

The engine overspeed lamp and the overspeed alarm are located on the operator's panel. The engine overspeed lamp and the overspeed alarm indicate that the engine speed has exceeding the maximum allowable speed for safe operation. The engine overspeed lamp and the overspeed alarm will be activated during an overspeed situation. The engine overspeed lamp and the overspeed alarm will remain activated for the duration of the overspeed condition.

Upon start-up, the Electronic Control Module (ECM) will perform a self test of the engine overspeed lamp and the overspeed alarm by illuminating the lamp and by sounding the overspeed alarm. The ECM will run the test for five seconds. The keyswitch must be in the ON position and the engine must not be running in order to perform the test.

The overspeed condition is logged as an event into the ECM memory. The circuit for the engine overspeed lamp and for the overspeed alarm can be tested through the use of the diagnostic test on AVSpare Electronic Technician (ET).

One terminal of the engine overspeed lamp and the overspeed alarm receives 24 VDC from the output of the ECM when the ECM signals the lamp to turn ON. The other terminal of the engine overspeed lamp and the overspeed alarm is connected to the digital return line.

Note: This feature is not present on machines that are equipped with the Vital Information Management System (VIMS).




Illustration 1g00931364

Test Step 1. Check for Connector Damage.

  1. Turn the keyswitch to the OFF position.

  1. Thoroughly inspect the ECM connector J1/P1. Thoroughly inspect the machine connector J2/P2. Inspect all of the other connectors. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" for details.

  1. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.

  1. Check the ECM connector (allen head screw) for the proper torque of 2.25 ± 0.25 N·m (20 ± 2 lb in).

  1. Check the customer connector (allen head screw) for the proper torque of 2.25 ± 0.25 N·m (20 ± 2 lb in).

  1. Check the harness and the wiring for abrasion and for pinch points.

Expected Result:

All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion or of pinch points.

Results:

  • OK - The connectors and wiring are okay. Proceed to Test Step 2.

  • Not OK - The connectors and/or wiring are not okay.

    Repair: Repair the connectors or wiring and/or replace the connectors or wiring.

    Stop.

Test Step 2. Check the Engine Overspeed Lamp.

  1. Remove the engine overspeed lamp. Inspect the engine overspeed lamp for damage.

Expected Result:

The engine overspeed lamp is undamaged.

Results:

  • OK - The engine overspeed lamp is in working condition. Proceed to Test Step 3.

  • Not OK - The engine overspeed lamp is damaged.

    Repair: Replace the engine overspeed lamp.

    Stop.

Test Step 3. Check the Operation of the Engine Overspeed Lamp and the Overspeed Alarm.

  1. Reinstall the engine overspeed lamp.

  1. Connect Cat ET to the ECM through the J31 cab service tool connector.

  1. Turn the keyswitch to the ON position. The engine should be off.

  1. Access the diagnostic test on Cat ET.

  1. Activate the override for the engine overspeed lamp.

  1. Monitor the engine overspeed lamp and the overspeed alarm.

  1. Deactivate the override for the engine overspeed lamp.

Expected Result:

The engine overspeed lamp or the overspeed alarm are not ON before the override is activated. The engine overspeed lamp and the overspeed alarm are ON after the override is activated. The engine overspeed lamp and the overspeed alarm turn OFF after the override is deactivated.

Results:

  • OK - The engine overspeed lamp and the overspeed alarm were ON during the override. The engine overspeed lamp and the overspeed alarm turned OFF after the override was deactivated.

    Repair: The engine overspeed lamp and the overspeed alarm are operating correctly.

    Stop.

  • Not OK - The engine overspeed lamp and/or the overspeed alarm did not turn ON. Proceed to Test Step 4.

  • Not OK - The engine overspeed lamp and the overspeed alarm turned ON. The engine overspeed lamp or the overspeed alarm did not turn OFF after the override was deactivated. Proceed to Test Step 5.

Test Step 4. Check the Harness for a Short to Ground Condition.

  1. Turn the keyswitch to the OFF position.

  1. Disconnect ECM connector J1/P1.

  1. Remove the engine overspeed lamp. Disconnect the wires from the terminals of the overspeed alarm.

  1. Measure the resistance between the following pins on the ECM connector:

    • P1-4 and P1-23

    • P1-4 and P1-13

    • P1-4 and P1-9

Expected Result:

The resistance is greater than 20,000 Ohms for each measurement.

Results:

  • OK - The resistance is greater than 20,000 Ohms for each measurement. Proceed to Test Step 6.

  • Not OK - The resistance is less than 20,000 Ohms for one of the measurements.

    Repair: The wire B948-BR is shorted to ground through one of the three wires in the engine harness. If the short is to wire 229-BK, wire B948-BR could be shorted to the engine block or to the chassis. If the short is not to wire 229-BK, locate the short in the engine harness or locate the short in the machine harness. Repair the connectors or wiring and/or replace the connectors or wiring.

    Stop.

Test Step 5. Check the Harness for a Short to Battery Condition.

  1. Turn the keyswitch to the OFF position.

  1. Disconnect ECM connector J1/P1.

  1. Remove the engine overspeed lamp. Disconnect the wires from the terminals of the overspeed alarm.

  1. Measure the resistance between the following pins on the ECM connector:

    • P1-4 and P1-70

    • P1-4 and P1-65

    • P1-4 and P1-51

    • P1-4 and P1-37

Expected Result:

The resistance is greater than 20,000 Ohms for each measurement.

Results:

  • OK - The resistance is greater than 20,000 Ohms for each measurement. Proceed to Test Step 6.

  • Not OK - The resistance is less than 20,000 Ohms for one of the measurements.

    Repair: The wire B948-BR is shorted to power through one of the four wires in the engine harness. Locate the short in the engine harness or in the machine harness. Repair the connectors or wiring and/or replace the connectors or wiring.

    Stop.

Test Step 6. Check for an Open in the Wiring that goes to the Engine Overspeed Lamp.

  1. Turn the keyswitch to the OFF position.

  1. Disconnect ECM connector J1/P1.

  1. Remove the engine overspeed lamp.

  1. Connect a wire jumper between the two terminals at the base of the engine overspeed lamp.

  1. Measure the resistance between P1-4 and P1-9 at ECM connector P1.

  1. Remove the wire jumper.

Expected Result:

The resistance measures less than 5 Ohms.

Results:

  • OK - The resistance is less than 5 Ohms. Proceed to Test Step 7.

  • Not OK - The resistance is more than 5 Ohms.

    Repair: There is an open or excessive resistance in the wiring and/or in the connectors between ECM connector P1 and the engine overspeed lamp. Repair the connectors or wiring and/or replace the connectors or wiring.

    Stop.

Test Step 7. Check for an Open in the Wiring that goes to the Overspeed Alarm.

  1. Turn the keyswitch to the OFF position.

  1. Disconnect ECM connector J1/P1.

  1. Remove the engine overspeed lamp.

  1. Connect a wire jumper between the two wires that were removed from the overspeed alarm.

  1. Measure the resistance between P1-4 and P1-9 at ECM connector P1.

  1. Remove the wire jumper.

Expected Result:

The resistance measures less than 5 Ohms.

Results:

  • OK - The resistance is less than 5 Ohms. Proceed to Test Step 8.

  • Not OK - The resistance is more than 5 Ohms.

    Repair: There is an open or excessive resistance in the wiring and/or in the connectors between ECM connector P1 and the engine overspeed lamp. The problem should be in the wiring between the overspeed alarm and the splice into the main harness. Repair the connectors or wiring and/or replace the connectors or wiring.

    Stop.

Test Step 8. Check the Voltage to the Engine Overspeed Lamp and the Overspeed Alarm at the ECM.

  1. Turn the keyswitch to the OFF position.

  1. Reinstall the engine overspeed lamp. Reconnect the wires that were disconnected from the terminals of the overspeed alarm.

  1. Remove the wire P1-4 (B948-BR) and wire P1-9 (998-BR) from the ECM connector P1. Install wire jumpers into the sockets for P1-4 and for P1-9.

    Note: The digital return will no longer be connected to the other sensors and switches. Additional diagnostic codes will be generated from the ECM. Clear the codes after you complete this test.

  1. Reconnect ECM connector J1/P1.

  1. Turn the keyswitch to the ON position. The engine should be off.

  1. Access the diagnostic test on Cat ET.

  1. Activate the override for the engine overspeed lamp.

  1. Measure the voltage between the wire jumpers in P1-4 and in P1-9.

  1. Deactivate the override for the engine overspeed lamp.

  1. Turn the keyswitch to the OFF position.

  1. Remove the wire jumpers and replace all wires. Reconnect ECM connector J1/P1.

Expected Result:

The voltage is 24 ± 3 VDC.

Results:

  • OK - The supply voltage is 24 ± 3 VDC. There is a problem in the wiring between the ECM and the engine overspeed lamp.

    Repair: Repair the connectors or wiring and/or replace the connectors or wiring.

    Stop.

  • Not OK - The supply voltage is not 24 ± 3 VDC.

    Repair: The ECM is not providing the correct voltage to the engine overspeed lamp. Replace the ECM. Refer to the diagnostic procedure Troubleshooting, "Replacing the ECM" before proceeding further.

    Stop.

Information System:

CS-563E, CP-563E, CS-573E, CP-573E, CS-583E, CP-583E, CS-663E, CP-663E and CS-683E Vibratory Soil Compactors Engine Oil Sample - Obtain
CS-563E, CP-563E, CS-573E, CP-573E, CS-583E, CP-583E, CS-663E, CP-663E and CS-683E Vibratory Soil Compactors Engine Oil Level - Check
3054E Industrial Engine Engine Valve Lash - Inspect/Adjust
R2900 Load Haul Dump Belts - Inspect/Adjust
3054E Industrial Engine Glow Plugs - Test
CB-434D, CB-534D, CB-534D Series XW and CB-564D Paving Compactors Power Supply Circuit of Electronic Control Module
14H Motor Grader Machine Systems Piston Pump (Hydraulic and Steering) - Remove
3524B Engine for Caterpillar Built Machines Water Pump - Install
14H and 16H Motor Graders Power Train Power Train
3512 and 3516 EUI Engines for 784B, 785B, 789B and 793B Off-Highway Trucks Service Engine Lamp
CP-563C and CS-563C Vibratory Compactors Engine Air Filter Primary Element - Clean/Replace
R2900 Load Haul Dump Automatic Brake Application System (Low Transmission Oil Pressure) - Test - If Equipped
CS-563E, CP-563E, CS-573E, CP-573E, CS-583E, CP-583E, CS-663E, CP-663E and CS-683E Vibratory Soil Compactors Engine Oil and Filter - Change
AP-1000D, AP-1055D, AP-655C, BG-2255C, BG-2455D and BG-260D Asphalt Pavers MID 039 - CID 1763 - FMI 02
M318C Excavator Machine Systems Hydraulic Hand Control - Remove - Stabilizer and Blade
M318C and M322C Excavators Machine Systems Hydraulic Hand Control - Install - Stabilizer and Blade
14H Motor Grader Machine Systems Metering Pump (Steering) - Remove and Install
938G Series II Wheel Loader and IT38G Series II Integrated Toolcarrier Hydraulic System Main Control Valve - IT38G Series II Integrated Toolcarrier
AP-1000D, AP-1055D, AP-655C, BG-2255C, BG-2455D and BG-260D Asphalt Pavers MID 039 - CID 0972 - FMI 02
3126B Machine Engines Sensors and Electrical Connectors
R2900 Load Haul Dump Maintenance Interval Schedule
Installation Instructions for the Machine Security System on the Medium Wheel Loaders{7631}
CB-634D Paving Compactor Machine Electronic Control System Reverse Propel
AP-1000D, AP-1055D, AP-655C, BG-2255C, BG-2455D and BG-260D Asphalt Pavers MID 039 - CID 0973 - FMI 02