DISC-FRICTION 6Y5352 - Caterpillar

System Operation Description:Use this procedure to troubleshoot a suspected problem with the engine starting system. Use this procedure if one of the diagnostic codes in Table 1 are active or easily repeated.
Table 1
Diagnostic Codes Table    
Description    Conditions which Generate this Code    System Response    
444-5 Starter Motor Relay : Current Below Normal     The output driver is off for at least 5 seconds. The ECM detects an open in the circuit for the starting motor solenoid for more than 5 seconds.     The code is logged.
The alarm output is activated.    
444-6 Starter Motor Relay : Current Above Normal     The output driver is on for at least 5 seconds. The ECM detects a short in the circuit for the starting motor solenoid for more than 5 seconds.     The code is logged.
The alarm output is activated.
The output driver automatically resets and the output driver continues to try to activate the circuit component.    The engine ECM contains the logic and the outputs for starting the engine. The logic for starting the engine is customer programmable. The logic responds to inputs from the following components: engine control switch, emergency stop switch, remote start switch, data link and other inputs.The ECM also has outputs that are used for communicating the engine current state of operation. One of the outputs sends a signal in order to indicate that the engine crank terminate speed has been achieved. Another output sends a signal that indicates that the engine is running. Both of these outputs are low side ECM drivers. The power for the circuits is provided at the electrical component and the ground circuit is provided by the ECM. Refer to Troubleshooting, "Indicator Lamp - Test" for information that is related to troubleshooting these circuits.The most likely causes of any of these diagnostic codes are a poor electrical connection or a problem in a wiring harness. The next likely cause is a problem with one of the solenoids that are related to the code. The least likely cause is a problem with the ECM.The ECM supplies +Battery voltage to the starting motor solenoid when the logic determines that start-up is needed. The ECM removes the voltage when the crank terminate relay is energized. The voltage is also removed if the customer programmable "Overcrank Time" has expired.If the engine is equipped with prelubrication, start-up may not be enabled until the prelube cycle is complete. If there is a problem with the prelubrication system, the start command may not be generated. Check that the engine is receiving sufficient oil pressure during the prelube cycle. Refer to Systems Operation/Testing and Adjusting for more information on the engine air starting system.
Illustration 1 g01760670
Schematic for the components of the engine starting systemTest Step 1. Inspect the Electrical Connectors and the Wiring
Remove the electrical power from the ECM.
Illustration 2 g01760975
Location of the ECM connectors for the engine starting system (typical left side engine view) (1) J2/P2 ECM connectors (2) Control harness connectors