ALARM 6T7622 - Caterpillar

Table 1
Diagnostic Codes Table    
Description    Conditions which Generate this Code    System Response    
168-1 Electrical System Voltage : Low     The battery supply voltage is less than 9 VDC for two seconds.
The engine ECM has been powered for three seconds.
The engine is not being cranked.     The code is logged if the engine is running.    
168-2 Electrical System Voltage : Erratic, Intermittent, or Incorrect     The engine is running. The battery voltage falls below 9 VDC for at least .06 seconds. The voltage returns above 9 VDC.
or
Three voltage readings in the last seven seconds were below 9 VDC.    Unswitched battery voltage is supplied to the ECM at P1-52 and P1-53. The negative battery is supplied to the ECM at P1-63 and P1-65. 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 g01145646
Typical schematicTest Step 1. Inspect Electrical Connectors and Wiring
Check all circuit breakers.
Turn the keyswitch to the OFF position.
Illustration 2 g01234146
Location of ECM connectors
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect the connections f