IMPELLER-PUMP 9Y3778 - Caterpillar

Probable Causes
Batteries and/or battery cables
Starting motor solenoid and/or starting circuit
Starter motor pinion or flywheel ring gear
Low air pressure
Static load
Wiring for the starting system
Internal mechanical problem
There is a problem with the harness code for the slave ECM.Recommended Repairs
Batteries and/or Battery Cables
Inspect the main power switch, battery posts, and battery cables for loose connections and corrosion. If the battery cables are corroded, remove the battery cables and clean the battery cables. Tighten any loose connections.
Inspect the batteries.
Charge the batteries. Refer to Special Instruction, SEHS7633, "Battery Test Procedure".
Load test the batteries. Refer to Special Instruction, SEHS9249, "Use of 4C-4911 Battery Load Tester for 6, 8 and 12 Volt Lead Acid Batteries".Starting Motor Solenoid or Starting Circuit
Test the operation of the starting motor solenoid.If the solenoid does not operate properly, install a new solenoid.
Check the wiring to the starting motor solenoid.Starting Motor or Flywheel Ring Gear
If the pinion engages the flywheel but the flywheel does not turn, there may be a problem with the starting motor. If the starting motor turns but the flywheel does not turn, inspect the gear teeth, the clutch jaws, or other parts.Inspect the pinion and the flywheel ring gear for damage. If the teeth of the pinion and/or the flywheel ring gear are worn or broken, replace the parts.If the pinion does not engage correctly with the flywheel, the pinion shaft may be stuck. Remove the pinion. Grease the splines of the drive shaft and the pinion.If the pinion does not engage the flywheel, the clutch jaws may be broken.Before you remove the starting motor, turn the crankshaft by hand. Ensure that a mechanical failure inside the engine is not preventing the crankshaft from turning. If the crankshaft will turn by hand, try the starting motor again. If the starting motor does not turn the crankshaft, remove the starting motor. Repair the starting motor or replace the starting motor.Low Air Pressure
Determine the cause of the low air pressure. Inspect the air lines for leaks. Repair any leaks in the air lines.Static Load
Make sure that the driven equipment is not preventing the crankshaft from turning. Try to turn the crankshaft by hand. If necessary, disengage the driven equipment and test the engine.Wiring
If you suspect that the wiring is faulty, refer to Troubleshooting, "Electrical Power Supply".Internal Mechanical Problem
If the crankshaft will not turn and the driven equipment is disengaged, remove the spark plugs. Check for fluid in the cylinders. If this is not the problem, the engine must be disassembled in order to investigate internal mechanical problems. Possible internal problems include the following conditions:
Bearing seizure
Piston seizure
Valve and piston contactCheck the Harness Code for the Slave ECM
The harness inside the terminal box for the slave ECM has a jumper wire (harness code) that connects terminals J3-29 and J3-60. The ECM that is connected to the harness reads the harness code. This allows the ECM to operate as the slave ECM. The jumper wire must be connected in