The diagnostic code consists of a component identifier (CID) and a failure mode identifier (FMI). A "DIAG" status indicator is also shown on the upper display. The CID informs the operator of the component that may have failed. The FMI describes the type of failure that has occurred. When the diagnostic code is active the DIAG status indicator FLASHES.
Only inactive diagnostic codes are stored in the fault log. An active diagnostic code that is programmed to be treated as an alarm fault becomes inactive when the problem is no longer occurring. An active diagnostic code that is programmed to be treated as a shutdown fault becomes inactive when the problem is no longer occurring AND the engine control switch (ECS) is turned to the OFF/RESET position. Active diagnostic codes are indicated when "DIAG" is FLASHING. When the problem becomes inactive "DIAG" is ON CONTINUOUSLY. The GSC stores a maximum of 12 diagnostic codes in the fault log. If an additional diagnostic code becomes inactive, the GSC automatically clears the earliest inactive diagnostic code. The GSC then places the new inactive diagnostic code in the fault log.
The GSC automatically clears any inactive diagnostic codes that have been stored in the fault log longer than 750 hours. For example, if a diagnostic code is logged at 10 hours, then the GSC clears the diagnostic code when the hour meter is at 760 hours. If a diagnostic code is logged at 20 hours, then the code remains logged until the hour meter is at 770 hours. This feature prevents old diagnostic codes from clogging the fault log, if service personnel have forgotten to clear the fault log after correcting diagnostic codes.
When an active diagnostic code changes to an inactive diagnostic code, the GSC will function in the following manner.
- The diagnostic code is recorded in the fault log of the GSC.
- If no other active diagnostic codes are present the DIAG indicator will stop FLASHING and the DIAG indicator remains on CONTINUOUSLY.
- The fault alarm indicator that was FLASHING turns OFF or the shutdown fault indicator that was FLASHING turns OFF.
Procedure To View The Fault Log
Note: For a list of all diagnostic codes, seeTesting And Adjusting, "Troubleshooting Diagnostic Codes".
Note: Service Mode cannot be entered when the ECS is in the AUTO position.
Note: Any active shutdown fault must be made inactive in order to access service mode. A FLASHING shutdown indicator indicates that a shutdown fault exists. To temporarily change a shutdown fault from an active shutdown fault to an inactive shutdown fault, turn the ECS to the OFF/RESET position. To permanently change a shutdown fault from an active shutdown fault to an inactive fault, the fault must not be occurring. The ECS must also be turned to the OFF/RESET position. If the jumper that electrically connects terminal 6 to terminal 9 is not installed on the ECS, then the GSC will not power up in OFF/RESET and any active shutdown fault must be corrected before entering service mode.
- Press the "SERVICE MODE" key in order to enter Service Mode. "OP 1" is showing on the lower display. See Systems Operation, "Service Mode"for more information.
- Press "SELECT" key. If more than one diagnostic code is present then the codes begin scrolling on the display. The number of occurrences is shown above the "COUNT" indicator. The lower display shows the value from the hour meter at the first occurrence and the last occurrence of each diagnostic code.
- Press "SELECT" key. The diagnostic codes stop scrolling.
- Press "SCROLL RIGHT" key. If more than one count of a diagnostic code is logged then the first occurrence with a corresponding value from the hour meter is showing on the lower display.
- Press "SELECT" key. Diagnostic codes continue scrolling.
- Press "EXIT" key. "OP 1" is showing on lower display.
- Press "EXIT" key. The display is now in normal mode.