ENGINE AR-PRIM 20R0372 - Caterpillar

Logged Diagnostic Trouble Codes
When the ECM generates a diagnostic trouble code, the ECM logs the code in permanent memory. The ECM has an internal diagnostic clock. The ECM records the following information when a code is generated:
The hour of the first occurrence of the code
The hour of the last occurrence of the code
The number of occurrences of the codeThis information is a valuable indicator for troubleshooting intermittent problems.A code is cleared from memory when one of the following conditions occur:
The service technician manually clears the code.
A new code is logged and there are already ten codes in memory. In this case, the oldest code is cleared.Some diagnostic trouble codes may be easily triggered. Some diagnostic trouble codes may log occurrences that did not result in complaints by the operator. 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 control module. Diagnostic trouble codes that are logged repeatedly may indicate a problem that needs special investigation.Note: Always clear logged diagnostic trouble codes after investigating and correcting the problem which generated the code.Active Event Codes
An active event code represents a problem with engine operation. Correct the problem as soon as possible.Active event codes are listed in ascending numerical order. The code with the lowest number is listed first.Illustration 2 is an example of the operating range of a sensor.
Illustration 2 g01365757
Example of the typical operating range of a sensor
(1) This area represents the normal operating range of the engine parameter.
(2) In these areas, the engine is operating in an unsafe operating range of the monitored parameter. An event code will be generated for the monitored parameter. The sensor circuit does not have an electronic problem.
(3) In these areas, the signal from the sensor is outside of the operating range of the sensor. The sensor circuit has an electronic problem. A diagnostic code will be generated for the sensor circuit. Refer to Troubleshooting, "Diagnostic Trouble Codes" for additional information on diagnostic codes.Logged Event Codes
When the ECM generates an event code, the ECM may log the event code in permanent memory. The ECM has an internal diagnostic clock. The ECM will record the following information when an event code is generated:
The hour of the first occurrence of the code
The hour of the last occurrence of the code
The number of occurrences of the codeLogged events are listed in chronological order. The most recent event code is listed first.This information can be helpful for troubleshooting intermittent problems. Logged codes can also be used to review the performance of the engine.Clearing Event Codes
A code is cleared from memory when one of the following conditions occur:
The code does not recur for 100 hours.
A new code is logged and there are already ten codes in memory. In this case, the oldest code is cleared.
The service technician manually clears the code.Always clear logged event codes after investigating and correcting the problem which generated the code.Troubleshooting
To troubleshoot