CAP 7C8370 - Caterpillar

The probable root causes are listed in order below.
Emergency Stop Push button
ECS or Start/Run/Stop Switch
Air Shutoff Valves
Starting motor
Flywheel ring gear
Hydraulic cylinder lock
Internal engine problemPerform the following tests in order:
Ensure that the local emergency stop push button is in the OFF position. Ensure that the remote emergency stop switch is in the CLOSED position. Use the Caterpillar Electronic Technician (ET) to confirm the switch status. Check for CID-FMI 337-02. If the CID-FMI is active, refer to the diagnostic functional test Troubleshooting, "Emergency Stop Switch".
Check the Engine Control Switch (ECS) and verify proper operation. Use the Cat ET to confirm the switch status. If the engine has an ECS, refer to the diagnostic functional test Troubleshooting, "Engine Control Switch (ECS)".
Ensure that the air shutoff valves are not in the closed position. Refer to the diagnostic functional test Troubleshooting, "Air Shutoff System".
Test the operation of the starting motor. Ensure that air pressure is available to the air starting motor. Ensure that the air start solenoid valve is functioning properly. Refer to the diagnostic functional test Troubleshooting, "Starting Motor System".
Ensure that the timing pin is not left in the flywheel housing after you set the valve lash. Use the 9S-9082 Engine Turning Tool and attempt to manually turn the engine.
Inspect the engine accessories if the engine will not turn. Remove the engine accessories and inspect the engine accessories that can lock up the engine. Repair the engine accessories and/or replace the engine accessories. Refer to Systems Operation for additional information.
Remove injectors and check for fluid in the cylinders.
Disassemble the engine. Inspect the engine for internal component damage. Refer to Disassembly and Assembly Manual.