0344040 JOHNSON FITTING, Fuel

Table 1
Module Identifiers    
MID    Description    
30     Caterpillar Monitoring System    
36     Electronic Control Module (ECM) for the engine    
39     Machine Control Module (LHEX)    Component Identifier (CID) - The CID is a number with three or four digits. The CID indicates the component that generated the code. For example, the CID number 17 identifies the fuel shutoff valve.Failure Mode Identifier (FMI) - The FMI is a two digit code that indicates the type of failure. Table 2 is a list of the failure mode identifiers.
Table 2
Failure Mode Identifiers    
FMI    Description    
00     The data is valid, but the data is above the normal range of operation.    
01     The data is valid, but the data is below the normal range of operation.    
02     The data is erratic, intermittent, or incorrect.    
03     The voltage is above normal or shorted high.    
04     The voltage is below normal or shorted low.    
05     The current is below normal or the circuit is open.    
06     The current is above normal or the circuit is grounded.    
07     The mechanical system is not responding correctly.    
08     There is a frequency, a pulse width, or a period that is abnormal.    
09     There has been an abnormal update.    
10     There has been an abnormal rate of change.    
11     The failure mode is not identifiable.    
12     The device or the component is faulty.    
13     The device or the component is out of calibration.    
14-31     Reserved    Note: Do not confuse diagnostic codes with event codes. These events that are logged can be used in order to investigate the engine information. An example would be a low oil pressure event. An event is generated when the engine oil pressure is low but not out of the normal range for the sensor. This does not indicate a problem with the sensor. This event indicates a problem with the engine oil pressure. For information on event codes, see Troubleshooting, "Event Codes".Active Diagnostic Codes
An active diagnostic code represents a problem with the electronic control system. This problem should be investigated and any resulting findings should be corrected as soon as possible. When an active diagnostic code is generated, a diagnostic lamp will indicate the diagnostic code. If the condition that generates the diagnostic code occurs only for a brief moment, the message will disappear and the diagnostic code will be logged in the memory of the ECM.When an active diagnostic code is generated, a warning may be displayed on an electronic display such as the Caterpillar Monitoring System.Logged Diagnostic Codes
When the ECM generates a diagnostic code, the ECM will log the code in the permanent memory of the ECM. The ECM has a diagnostic clock that is internal. This clock records the hour of the first occurrence, the hour of the last occurrence, and the number of occurrences of the code. Knowing the timing of the code and knowing the frequency of the code can be a valuable indicator. These indicators are helpful when problems that are intermittent are being investigated.Note: Cat ET can be used to retrieve logged codes and Cat ET can also be used to erase logged codes. Logged diagnostic codes will automatically be deleted if no additional occurrences are recorded in 100 hours. Be aware of the following information when logged diagnostic codes are investigated.
Some diagnostic codes may log occurrences that did not result in operator complaints. A diagnostic code is logged at a specific time. This time should correlate to a complaint. A repair may not be necessary if there is no correlation.
The most likely cause of an intermittent problem is a faulty connection or damaged wiring. The next most likely cause of an intermittent failure is a component failure such as a sensor or a switch. The least likely cause of an intermittent problem is a failure of the ECM.
Diagnostic codes that are logged repeatedly may indicate a problem that needs special investigation.
The code number will direct you to a procedure in troubleshooting guide. If the symptoms continue, use the proper procedure for troubleshooting the symptoms that have been experienced by the operator. Refer to Troubleshooting, "Troubleshooting without a Diagnostic Code".Note: Always clear logged diagnostic codes after investigating and correcting the problem which generated the code.