SPACER 3699626 - Caterpillar

Table 1
Diagnostic Codes Table    
Code and Description    Conditions which Generate this Code    System Response    
168-0 Electrical System Voltage high - most severe (3)     The battery supply voltage is greater than 32 VDC for 0.5 seconds.
The engine's ECM has been powered for three seconds.
The engine has been running for at least 30 seconds.     The code is logged.    
168-1 Electrical System Voltage low - most severe (3)     The battery supply voltage is less than 9 VDC for 0.5 seconds.
The engine's ECM has been powered for three seconds.
The engine is running for at least 3 seconds.    
168-2 Electrical System Voltage erratic, intermittent, or incorrect     The battery voltage falls below 6 VDC and the voltage returns above 9 VDC for three voltage readings in the last seven seconds.
The engine is running.    Unswitched battery voltage is supplied to the ECM at P1-48, P1-52, P1-53, P1-55, and P1-57. The negative battery is supplied to the ECM at P1-61, P1-63, P1-65 and P1-67. The ECM receives the input from the keyswitch at P1-70 when the keyswitch is in the ON position or in the START position. When the ECM detects battery voltage at this input, the ECM will power up. When battery voltage is removed from this input, the ECM will power down. The ECM continuously receives battery voltage through the circuit breaker for the ECM.The ECM requires the keyswitch to be in the ON position in order to maintain communications with Caterpillar Electronic Technician (ET).
Illustration 1 g01385852
Schematic for the electrical power supply circuitTest Step 1. Inspect the Electrical Connectors and the Wiring
Remove electrical