STUD 2A5684 - Caterpillar

Use this procedure to troubleshoot an engine that will not crank.Probable Causes
Batteries and battery cables
Machine Security System (MSS)
Switches and/or circuit breakers
Starting motor solenoid and starting circuit
Starter pinion and flywheel ring gear
Engine accessories and transmission
Hydraulic cylinder lockRecommended Actions
Note: The procedures have been listed in order of probability. Complete the procedures in order.
Table 1
Troubleshooting Test Steps Values Results
1. Inspection of the Batteries and Battery Cables
A. Inspect the main power switch, battery posts, and battery cables for loose connections and for corrosion. If the battery cables are corroded, remove the battery cables and clean the battery cables. Tighten any loose connections.
B. Inspect the batteries.
C. Charge the batteries. Refer to Special Instruction, SEHS7633, "Battery Test Procedure".
Test the batteries. Refer to Special Instruction, SEHS9249, "Use of 4C-4911 Battery Load Tester for 6 v, 8 v, and 12 v Lead Acid Batteries".
Batteries
Result: The batteries and cables are OK.
Proceed to Test Step 2.
Result: The batteries and cables are not OK.
Repair: Make the necessary repairs.
2. Machine Security System (MSS)
A. Check that the correct ignition key is being used.
B. Check that the CAN Data Link is operating correctly. Refer to Troubleshooting, "CAN Data Link - Test".
MSS
Result: An incorrect ignition key is being used.
Repair: Obtain the correct key and confirm that the engine starts.
Result: A fault is identified on the CAN data link.
Repair: Make the necessary repairs.
Result: The correct ignition key is being used and the CAN data link is OK.
Proceed to Test Step 3.
3. Switches and/or Circuit Breakers (if applicable)
A. Check any switches and/or circuit breakers that may prevent engine cranking. For additional information, refer to the machine electrical schematic.
Switches and/or circuit breakers
Result: The switches and/or circuit breakers are OK.
Proceed to Test Step 4.
Result: The switches and/or circuit breakers are not OK.
Repair: Make the necessary repairs.
4. Starting Motor Solenoid and Starting Circuit
A. Test the operation of the starting motor circuit. Refer to Systems Operation, Testing, and Adjusting, "Electrical System" for additional information.
Starting motor solenoid and circuit
Result: The starting motor solenoid and circuit are OK.
Proceed to Test Step 5.
Result: The starting motor solenoid and circuit are not OK.
Repair: Make the necessary repairs.
5. Inspect the Starter Pinion and Flywheel Ring Gear
A. Test the operation of the starting motor.
B. Check the pinion clearance. Inspect the pinion and the flywheel ring gear for damage. Refer to Systems Operation, Testing, and Adjusting, "Electrical System" for additional information.
Starter pinion and flywheel ring gear
Result: The starter pinion and flywheel ring gear are OK.
Proceed to Test Step 6.
Result: The starter pinion and flywheel ring gear are not OK.
Repair: Make the necessary repairs.
6. Inspect Engine Accessories and the Transmission (if applicable)
A. Ensure free movement of the driveline.
B. Remove and inspect any engine accessories that may lock up the engine.
The following list identifies engine accessories that may lock up the engine:
Hydraulic pump that is driven from the rear gear group
Air compressor
Engine oil pump
Other components that are driven by the engine
Engine accessories and transmission
Result: The engine accessories and transmission are OK.
Proceed to Test Step 7.
Result: The engine accessories and transmission are not OK.
Repair: Make the necessary repairs.
7.