LINE AS 6N4731 - Caterpillar

Diagnostic codes are associated with failed electrical components or circuits. These components or circuits provide information to the GSC or the components or circuits receive information from the GSC. The diagnostic codes are designated as alarm faults or shutdown faults. See System Operation, "Shutdown Mode" for more information. See System Operation, "Alarm Mode"for more information. Alarm Mode Sequence Of Operation - When an alarm fault occurs, the GSC performs the following steps.
The GSC activates the alarm mode.
The fault alarm indicator FLASHES.
When the alarm codes key is pressed, the corresponding diagnostic code (CID FMI) is shown on the upper display.
The engine continues to run or the engine is able to start. Shutdown Mode Sequence Of Operation - When a shutdown fault occurs, the GSC performs the following steps.
The GSC activates shutdown mode.
The fault shutdown indicator FLASHES.
The corresponding diagnostic code (CID FMI) is immediately shown on the upper display.
The engine is shut down or the engine cannot be started. The diagnostic fault code (CID FMI) closely identifies the cause of the fault. Each diagnostic fault consists of two identifiers and an indicator. The identifiers are shown on the upper display. Service personnel interpret the identifiers in order to assist with troubleshooting. The indicators are listed below. Component Identifier (CID) - The CID is a three digit code. The code that is indicated corresponds to a faulty component. The CID is shown on the upper display. For example if the engine magnetic pickup (MPU) is faulty then "190"would be displayed. See the Testing And Adjusting, "Diagnostic Fault Codes" for a list of CID codes. Control System Identifier - The control system identifier is a single digit. There are two possible control systems that can generate a diagnostic code. If an "E" is showing on the display, the engine ECM has generated the diagnostic code. If there is no "E" on the display, the GSC has generated the diagnostic code.Failure Mode Identifier (FMI) - The FMI is a two digit code. The FMI tells the type of failure that has occurred. The FMI is shown on the upper display at the same time as the CID. For example, FMI "3" means that the signal voltage is too high. See Testing And Adjusting, "Diagnostic Fault Codes" for a list of FMI codes.DIAG indicator - When "DIAG" is FLASHING, the diagnostic fault code (CID FMI) that is showing on the upper display is active. When "DIAG" is ON CONTINUOUSLY, there is an inactive diagnostic fault. The CID and the FMI will be recorded in the fault log. Also, see System Operation, "Fault Log Viewing OP1". When the"DIAG" display is not showing then there are NO diagnostic fault codes.
Illustration 1 g00606749
Upper Display that is showing a "CID 190 FMI 3" Diagnostic Fault CodeNote: The GSC response (alarm or shutdown) to four diagnostic faults is programmable by service personnel. The response that is usually programmed into the GSC is for an alarm. P04 would then be "0". When a shutdown response is programmed P04 would be "1".