Usage:
Diagnostic Codes
Diagnostic codes are used by the electronic system to alert the operator that a problem exists and indicates to the service technician the nature of the problem.
The CID, or Component IDentifier, tells which component in the system the diagnostic code is for. The FMI, or Failure Mode Identifier indicates what the failure mode is.
Diagnostic Codes may be viewed using Electronic Service Tools. To troubleshoot a Diagnostic Code, refer to the reference table in this section under the specific code number. The code number will direct you to a procedure in Section 5: System Functional Tests.
Do not confuse diagnostic codes (Active or Logged) with diagnostic events! Events can be logged in the ECM to track operating information about the engine conditions. An example would be a low fuel pressure event. A logged event code is generated when the engine fuel pressure is low, but not out of range for the sensor to communicate with the ECM, which would generate a diagnostic code. This occurrence does not indicate a problem with the engine sensor, rather it would be an indication there is a problem with engine fuel pressure.
Active Diagnostic Codes
An ACTIVE diagnostic code represents a problem with the electronic control system that should be investigated and corrected as soon as it is practical.
When an ACTIVE diagnostic code is generated, a display module such as the Electronic Monitoring may indicate the diagnostic code. If the condition generating the diagnostic occurs only for a brief moment, the message will disappear and the diagnostic code will be LOGGED in the ECM memory.
Logged Diagnostic Codes
When the ECM generates a diagnostic code, it usually logs the code in permanent memory within the ECM. The ECM has an internal diagnostic clock and will record the hour of the first occurrence, the hour of the last occurrence and the number of occurrences of the code. Knowing when and how often the code was generated can be a valuable indicator when troubleshooting intermittent problems.
NOTE: The ECAP Electronic Service Tool can be used but does not support all logged codes.
Logged codes can be retrieved or erased using an Electronic Service Tool. Logged diagnostic codes will automatically be deleted if no additional occurrences are recorded in 100 hours.
When investigating logged diagnostic codes, keep in mind the following information.
- * Some diagnostic codes may be sensitive, and may log occurrences that did not result in operator complaints. If the time the code was logged does not correlate to a complaint, there may be nothing to fix.
- * The most likely cause of an intermittent problem is a faulty connection or damaged wiring. Next likely is a component failure (sensor or switch). Least likely is failure of the ECM itself.
- * Diagnostic codes that are logged repeatedly may indicate a problem that needs special investigation.
- * The most likely cause of an intermittent problem is a faulty connection or damaged wiring. Next likely is a component failure (sensor or switch). Least likely is failure of the ECM itself.
To troubleshoot a logged diagnostic code, refer to the Diagnostic Code Cross Reference to Functional Test Procedures in this section under the specific code number. The code number will direct you to a procedure in Section 5: Functional Test Procedures. If the symptoms continue, use the proper procedure for troubleshooting the symptoms that have been experienced by the operator. Refer to Section 3: Troubleshooting Without a Diagnostic Code.
NOTE: Always clear logged diagnostic codes after investigating and correcting the problem which generated the code.
Logged Events
The ECM can log events. Events refer to engine operating conditions such as low fuel pressure or high Engine Overspeed Warning. Logged events do not indicate an electronic system problem, but may indicate an engine system problem.
Programmable Shutdown, Alarms and Derates
On some applications, shutdown, alarms and derates are programmable. The Electronic Service Tool can be used to turn these features ON and OFF. When the features are turned ON, the display will appear on an electronic monitoring module (i.e. Computerized Monitoring System,) and an EVENT will also be logged in the ECM. When the features are turned OFF, the display will not appear on a monitoring module, but an EVENT will still be logged. Refer to Section 2: Programmable Parameters for additional information.
Using the ECAP to Display ACTIVE or LOGGED Diagnostic Codes
1. Connect an ECAP to the Service Tool Connector.
2. Turn the keyswitch to the ON position, engine OFF.
3. Each diagnostic code CID and FMI are listed and followed by a text description.
4. The ECAP also displays number of times the diagnostic code occurs and the engine hours at the first occurrence of the diagnostic code.
5. The diagnostic status display is located on the far right of the display window.
- The ACTIVE bar indicates the diagnostic is occurring.
Figure 4.1 - ECAP Display Screen
Using ET to Display ACTIVE Diagnostic Codes
1. Connect ET and the Communication Adapter Tool to the Service Tool Connector and run the ET Program.
2. Turn the keyswitch to the ON position, engine OFF.
3. Select the Display Active Diagnostic option from the Tools Menu.
4. Each Diagnostic Code CID and FMI are listed and followed by a text description.
Figure 4.2 - ET Active Diagnostic Code Screen
Using ET to Display LOGGED Diagnostic Codes
1. Connect ET and the Communication Adapter Tool to the Service Tool Connector and run the ET Program.
2. Turn the keyswitch to the ON position, engine OFF.
3. Select the Display Logged Diagnostics option from the Tools Menu.
4. Each Diagnostic Code CID and FMI are listed and followed by a text description.
Figure 4.3 - ET Logged Diagnostic Code Screen
Diagnostic Terminology
- Module Identifier (MID)
- Two or three digit code which is assigned to each module or control system.
- Component Identifier (CID)
- Two or three digit code which is assigned to each component or system.
- Failure Mode Identifier (FMI)
- Type of failure the component experienced (adopted from SAE standard practice J1587 diagnostics).
- Active Code
- The CID and FMI can be sent through the data link through the display module or through the Communication Adapter Tool, then to the Electronic Service Tool or various electronic display modules.
- Logged Code
- The diagnostic will be entered into the permanent memory (Diagnostic Log) when it becomes active. The number of occurrences will be saved in the "good to faulty counter" in the permanent memory (Diagnostic Log). First and last occurrence time (engine hours) will also be saved in the permanent memory (Diagnostic Log). This information is then available for display on the Electronic Service Tool.
Quick Reference Sheet For Diagnostic Codes.
