SEAL 2090229 - 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
J1939 Code and 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. Electrical power from the batteries is supplied to the following components:
Electronic Control Module (ECM)
Exhaust Temperature Module (ETM)
Fuel actuator
Operator Control Panel (OCP)
Throttle actuator
Voltage converterThese components are electrically protected by four circuit breakers that are located at the ECM control box. The ECM control box is mounted on the top front 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 OCP. Terminal location P1-70 is used for this purpose. Keyswitch power is available at this terminal location when the operator initiates a "RUN" or "STOP" command at the OCP. When the engine ECM detects battery voltage at the keyswitch input, the ECM will power up. When battery voltage is removed from this input, the ECM will power down.The ECM, the fuel actuator, and the throttle actuator receive power from an unswitched battery circuit via a breaker in the ECM control box. The Temperature Control Module (TCM), OCP, and voltage convertor each utilize a dedicated circuit breaker in the control box.Engine control is initiated via a set of soft keys at the OCP by the operator. The various control commands are sent to the ECM via the CAN data link. The ECM monitors the status of these engine commands in order to determine changes to the engine