SEAL-O-RING 1725635 - Caterpillar

System Operation Description:Use this procedure to troubleshoot the electrical system if a problem is suspected with the circuit for electrical power supply. Also use this procedure if one of the diagnostic codes in Table 1 is active or easily repeated.
Table 1
Diagnostic Codes Table    
Description    Conditions which Generate this Code    System Response    
158-2 Keyswitch Battery Potential : Erratic, Intermittent, or Incorrect     The Electronic Control Module (ECM) has detected three transitions of the signal for the keyswitch within one second.     The code is logged.
The red stop lamp is illuminated.
The engine is shut down.
The ECM is latched.    
168-2 Battery Potential / Power Input 1 : Erratic, Intermittent, or Incorrect     The input voltage to the ECM has dropped below 6 v and the input voltage has risen above 9 v three times within 7 seconds.     The code is logged.
The amber warning lamp is illuminated.    
168-3 Battery Potential / Power Input 1 : Voltage Above Normal     The input voltage to the ECM has risen above 32 v for one second.     The code is logged.
The amber warning lamp is illuminated.
The ECM will use default values for all of the engine sensors that are powered.
The status of the "Battery Voltage" parameter is reported as "Data Error" by Caterpillar Electronic Technician (ET).    
168-4 Battery Potential / Power Input 1 : Voltage Below Normal     The input voltage to the ECM has dropped below 18 v for one second.     The code is logged.
The red stop lamp is illuminated.
The engine is shut down.
The ECM will use default values for all of the engine sensors that are powered.
The status of the "Battery Voltage" parameter is reported as "Data Error" by Cat ET.    
3542-3 Requested Engine Control Mode : Voltage Above Normal     The ECM has detected a simultaneous open circuit condition for the engine stop circuit and the start circuit for at least 2 seconds.     The code is logged.
The red stop lamp is illuminated.
The engine is shut down.    
3542-4 Requested Engine Control Mode : Voltage Below Normal     The ECM has detected the simultaneous grounding of the engine stop circuit and the start circuit for at least 2 seconds.     The code is logged.
The red stop lamp is illuminated.
The engine is shut down.    Electrical power from the batteries is supplied to the following components:
Electronic Control Module (ECM)
Engine Control Switch (ECS)
Fuel actuator
Messenger
Throttle actuator
Voltage converterThese components are electrically protected by two circuit breakers that are located at the breaker panel. The breaker panel is mounted to the right side of the engine.The cause of an intermittent problem with the power supply can occur on either the positive side or the negative side of the power supply.The engine ECM receives keyswitch power from the engine control switch. Terminal location P1-40 is used for this purpose. Keyswitch power is available at this terminal location when the engine control switch is in the RUN position and in the STOP position. When the engine ECM detects battery