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| Illustration 1 | g00427558 |
Diagnostic Example (1) First display. (2) Second display. (3) Module identifier (MID). (4) Service code indicator (SERV CODE). (5) Component identifier (CID). (6) Failure Mode identifier (FMI). | |
Service mode is mode 3. The main display module detects faults that occur with sensor inputs, sender inputs, and main display module outputs while the main display module is in normal mode. The signal is at the contact of the main display module. 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 when the CID FMI is not present.
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 output
- Sensor inputs
- Harness code
Note: The main display module does not detect the diagnostic code for the switch input.
Service personnel can see the diagnostic codes and service personnel can troubleshoot the diagnostic codes when the main display module has detected a CID FMI. All detected problems are shown in the display area as a diagnostic code. The diagnostic codes can be placed on hold and the diagnostic codes can be cleared while the main display module is in service mode.
Note: Diagnostic codes from other machine systems under electronic control are shown in the display area of the main display module when the main display module is in Service Mode. The CAT data link allows the transfer of diagnostic information from other electronic control modules to the main display module. This diagnostic information is then shown when the main display module is in service mode. The diagnostic code for faults from other electronic control modules has a MID that is unique to the control. These diagnostic codes can scroll similarly to the diagnostic codes from the Caterpillar Monitoring System. See the following description of Module Identifier (MID).
The diagnostics of the Caterpillar Monitoring System are available to assist with the troubleshooting of diagnostic codes when the main display module is placed in service mode. A diagnostic code is used to specify each CID FMI. 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 that is shown in the same area. The electronic control module that has diagnosed the problem is logged by the MID. The following examples are of some MID.
- Caterpillar Monitoring System ... 030
- Engine Control (ADEM) ... 036
- Machine Control System ... 039
- Engine Control (ADEM) ... 036
See the table for the Module Identifier (MID) on the Electrical System Schematic for the machine that is being serviced for the most complete list. To troubleshoot diagnostic codes, use the service manual for the control that detected the CID FMI.
Component Identifier (CID) - The components that are faulty are noted by the CID. These components are examples: transmission oil temperature sensor, speed sensor, action lamp and boost pressure sensor. The CID is a four digit code that is shown on the six digit display area. The CID and the FMI are shown together after the MID has been displayed. See the table for "Diagnostic Codes For The Caterpillar Monitoring System" in the Troubleshooting, " Diagnostic Code List". This will show a list of component identifiers for the main display module.
Failure Mode Identifier (FMI) - The FMI tells the type of failure that has occurred. The following situations are examples: voltage above normal, current below normal and abnormal frequency. 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 the table for "Detected Faults" in Troubleshooting, "Diagnostic Code List". This table will show a list of failure mode identifiers for the main display module.
When 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 and FMI. This is maintained as long as the service and clear inputs remain open. Troubleshooting is performed while the diagnostic code is on hold.
Note: The display shows "- - -" when the main display module has no diagnostic codes.
All diagnostic codes are shown one at a time in the display area when the diagnostic codes are scrolling. Grounding the service input causes the display to scroll when the main display module is in service mode. This will momentarily show the MID. The display will show the CID and the FMI that corresponds. Removing ground from the service input stops the scrolling when the diagnostic code that is desired is shown. The diagnostic code that is shown is now on hold.
Note: The diagnostic codes from other electronic control modules can be shown on the display. Use the same procedure in order to place the diagnostic codes on hold.
Troubleshooting Intermittent Diagnostic Codes
Diagnostics are provided in order to assist service personnel during troubleshooting of intermittent problems. The service code indicator ("SERV CODE") is shown when the diagnostic code is present. This can aid in troubleshooting of an intermittent CID FMI. Gently shaking the harness connectors will aid the checking of intermittent diagnostic codes. The service code indicator changes from "SERV CODE" that is OFF to "SERV CODE" that is ON. This will occur when the CID FMI changes status. The action alarm SOUNDS briefly during the change of status when the diagnostic code is on hold for a CID FMI. These diagnostics signal the service personnel while inspections are performed. These diagnostics assist in troubleshooting intermittent problems by one service person.
A diagnostic code is removed from the memory of the main display module when the diagnostic code has been cleared. When a CID FMI is corrected, it is necessary to remove the corresponding diagnostic code from the memory of the main display module. In order to remove the diagnostic code from the memory, place the diagnostic code on hold and ground the clear input. The memory of the main display module saves a diagnostic code until the code is cleared. The main display module does not allow clearing of a diagnostic code that corresponds to a CID FMI which is present.
Note: The diagnostic codes from other electronic control modules should be cleared by using the main display module.
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| Illustration 2 | g00427558 |
Diagnostic Example (1) First display. (2) Second display. (3) Module identifier (MID). (4) Service code indicator ("SERV CODE"). (5) Component identifier (CID). (6) Failure Mode identifier (FMI). | |
Brief Explanation
Illustration 2 shows a main display module that is currently receiving a signal. This signal is from the engine coolant temperature sensor and the signal is out of range.
Detailed Explanation
MID (3) - "030". This code concerns the Caterpillar Monitoring System. The Caterpillar Monitoring System service manual should be used to troubleshoot the diagnostic code. If the MID that was shown was "039", the diagnostic code would concern the machine control. The service module for the machine control should be used to troubleshoot the diagnostic code.
CID (5) - "0110". This code means that a problem has occurred in the sensor circuit for the engine coolant temperature of MID "030". See the table "Diagnostic Codes For Caterpillar Monitoring System" in Troubleshooting, " Diagnostic Code List". This will show a list of the component identifiers for the Caterpillar Monitoring System.
FMI (6) - "08". This identifier means that a signal of abnormal frequency, pulse width or period is being received concerning CID "0110". See the table "Diagnostic Codes For Caterpillar Monitoring System" in Troubleshooting, " Diagnostic Code List". This table will show a list of failure mode identifiers for the Caterpillar Monitoring System.
Service code indicator (4) is ON in Illustration 2. When the main display module is in service mode, the service code indicator (4) functions as a fault present indicator. Therefore, the CID "0110" diagnostic code is present. The service code indicator changes from ON to OFF when the CID "0110" diagnostic code changes status. Also, the action alarm sounds when the CID "0110" diagnostic code changes status. This action will take place while the main display module is in service mode.