3500B Locomotive Engines Caterpillar

Diagnostic codes alert the operator that a problem exists. Diagnostic codes indicate the nature of the problem to the service technician. Diagnostic codes consist of the MID, CID and FMI. The module identifier (MID) indicates the electronic module that generated the diagnostic code. The component identifier (CID) indicates the component in the system. The failure mode identifier (FMI) indicates the failure mode that is present. Diagnostic codes may be viewed on an Electronic Service Tool or one of the various electronic display modules. Do not confuse diagnostic codes with diagnostic events.

Active Diagnostic Codes

An Active diagnostic code represents a problem with the electronic control system. This problem should be corrected as soon as possible. When a active diagnostic code is generated, a display module such as the Caterpillar Monitoring System may produce a warning.

Logged Diagnostic Codes

When the ECM generates a diagnostic code the ECM logs the code in permanent memory. The ECM has an internal diagnostic clock. The ECM will record the hour of the first occurrence of the diagnostic code. The ECM will record the hour of the last occurrence of the diagnostic code. The ECM will record the number of occurrences of the code. This information is a valuable indicator for troubleshooting intermittent problems. Any Logged diagnostic codes will automatically be deleted if no additional occurrences are recorded in 100 hours. Some diagnostic codes may be easily triggered. Some diagnostic codes may log occurrences that did not result in complaints. The most likely cause of an intermittent problem is a faulty connection or damaged wiring. The next likely cause is a component failure. The least likely cause is the failure of the ECM. Diagnostic codes that are logged repeatedly may indicate a problem that needs special investigation.

If the symptoms continue, use the proper procedure for troubleshooting the symptoms that have been experienced by the operator.

Note: Always clear logged diagnostic codes after investigating and correcting the problem which generated the code.

Diagnostic Terminology

Module Identifier (MID)

The module identifier (MID) indicates the electronic module that generated the diagnostic code. The following list contains module identifiers that could be in your system.

• The module identifier (26) indicates the Computerized Monitoring System.

• The module identifier (30) indicates the Caterpillar Monitoring System.

• The module identifier (36) indicates the primary engine ECM.

• The module identifier (47) indicates the secondary engine ECM.

• The module identifier (49) indicates the VIMS and/or the VIDS.

• The module identifier (81) indicates the electronic control module for the vibratory powertrain controller.

• The module identifier (82) indicates the electronic control module for the implement.

• The module identifier (97) indicates the electronic control module for the customer communication module.

• The module identifier (111) indicates the integrated temperature sensing module.

Component Identifier

• The component identifier (CID) indicates a specific component in the system.

Failure Mode Identifier (FMI)

• The FMI (00) indicates that the data is above the normal range.

• The FMI (01) indicates that the data is below the normal range.

• The FMI (02) indicates a incorrect signal.

• The FMI (03) indicates that the voltage is above the normal range.

• The FMI (04) indicates that the voltage is below the normal range.

• The FMI (05) indicates that the current is below the normal range.

• The FMI (06) indicates that the current is above the normal range.

• The FMI (07) indicates that there is an improper mechanical response.

• The FMI (08) indicates an abnormal signal.

• The FMI (09) indicates an abnormal update.

• The FMI (10) indicates an abnormal rate of change.

• The FMI (11) indicates that the failure mode is not identifiable.

• The FMI (12) indicates that a device or a component failed.

• The FMI (13) indicates that a component is out of calibration.