TUBE AS 4425148 - Caterpillar

The main display module detects diagnostic codes that occur with sensor inputs, sender inputs, and main display module outputs. The main display module must be in the normal mode to detect those diagnostic codes. A diagnostic code is detected when the signal is outside a valid range. The main display module then records the diagnostic code. The diagnostic code remains stored for future reference.The main display module detects diagnostic codes and the main display module diagnoses problems in the following circuits:
Display output modules
Action alarm output
Action lamp outputNote: The main display module does not detect problems with the switch inputs.Service personnel can see the diagnostic codes and service personnel can troubleshoot the diagnostic codes when the main display module has detected a problem. All detected failures are shown in the display area as diagnostic codes. The diagnostics of the monitoring system are available to assist with the troubleshooting of failures when the main display module is placed in service mode. A diagnostic code is used to specify each problem. The diagnostic code is made up of three identifiers (MID, CID, and FMI). These identifiers are shown in the display area. The display area continuously changes between the following identifiers when the diagnostic code is on hold: Module Identifier (MID) - The MID is a three-digit code that is shown on the display area. The MID is shown for approximately one second before the diagnostic code is displayed. The ECM that has diagnosed the failure is logged by the MID. An example of the MID follows: Machine ECM ... 039See the table for the Module Identifier (MID) on the Electrical System Schematic for the machine that is being serviced for the most complete list. In order to troubleshoot diagnostic codes, use the Service Manual for the control that detected the problem. Component Identifier (CID) - The components that have failed are noted by the CID. The following components are examples:
Transmission oil temperature sensor
Speed sensor
Action lamp
Boost pressure sensorThe CID is a four-digit code that is shown on the six-digit display area of the Digital Data window. The CID and the FMI are shown together after the MID has been displayed.Failure Mode Identifier (FMI) - The FMI reports the type of failure that has occurred. The FMI is a two-digit code that is shown on the six-digit display area. The CID and the FMI are shown after the MID is displayed. The CID and the FMI are separated by a decimal point ".". See Troubleshooting, " Diagnostic Code List". The table for the Module Identifier (MID) on the Electrical System Schematic will show a list of FMIs for the main display module. Examples of the FMIs follow:
Voltage above normal
Current below normal
Abnormal frequencyWhen the main display module enters the service mode, the MID, the CID, and the FMI are shown. At this time, the diagnostic code that is shown is on hold. The display area continuously changes between the following identifiers when the diagnostic code is on hold:
MID
CID
FMIThe display is maintained as