3500C Marine Engines Caterpillar

Diagnostic Codes

Diagnostic trouble codes are generated by the Electronic Control Module (ECM) in order to alert the operator that a problem has been detected. The problem can be in the electronic system or in the mechanical system. Diagnostic trouble codes are used by the service technician to assist in the identification of the nature of the problem. Caterpillar Electronic Technician (ET) is a software program that can be used by the service technician in order to view the diagnostic code information. Refer to Troubleshooting, "Electronic Service Tools" for detailed information that is related to the functionality of Cat ET.

The CAN data link is used by the ECM to communicate with controllers, display modules, and electronic service tools. The ECM transmits information and the ECM receives information over the CAN data link. The communications protocol and the diagnostic messages over the CAN data link follow the SAE J1939 industrial standards.

Note: The SAE J1939 industrial standards refer to the control module for the engine as the Electronic Control Unit (ECU). This manual refers to this control module as the Electronic Control Module (ECM).

Communications with electronic service tools aid the technician in diagnostics and troubleshooting for the engine and the engine subsystems. When a problem with the engine is detected by the ECM, the ECM communicates information about the problem over the CAN data link. The problem may be physically detected by one of the input or output circuits by the ECM. A problem can also be communicated via the data link to the ECM. The ECM transmits this information over the data link in a form of a diagnostic trouble code and code description.

The diagnostic trouble code has a format of a two-element code. The following terms describe the elements of the code:

Suspect Parameter Number (SPN) - The SPN is a code which is assigned to each component. The SPN identifies the origin of the problem.

Failure Mode Identifier (FMI) - The FMI is used with the SPN in order to provide more information that relates to the problem. The FMI may indicate that a problem with an electronic circuit or an electronic component has been detected. The FMI may also indicate that an abnormal operating condition has been detected.

The codes are displayed in the form “SPN-FMI”. The ECM also attaches a text description to the message that is transmitted over the data link. This text description is used to describe the SPN-FMI code.

The failure mode identifiers can be divided into two categories:

• Codes that indicate that a problem with an electronic circuit or an electronic component has been detected

• Codes that indicate that an engine event or a system event has been detected

The failure mode of the fault is determined by evaluating the electronic signal from the suspect circuit. Typically, the first category of code is generated when the signal for the circuit is outside the range of the sensor. The second category of code is an engine event. An engine event indicates that the sensor signal is OK, but the signal is outside the normal operating range of the engine parameter. Illustration 1 is an example that represents the evaluation of a sensor signal by the ECM.

Illustration 1	g01950177
Example of the typical electrical signal 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. A diagnostic code that indicates an engine event will be generated for the monitored parameter. The sensor circuit does not have an electronic problem. Refer to Systems Operation, "Engine Monitoring System" for additional information that is related to engine events. (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 trouble code that indicates that a problem with the circuit has been detected will be generated.

When you troubleshoot a diagnostic trouble code, be sure to evaluate the problem from the viewpoint of an interpretation of the electrical signal. Refer to the above illustration for an evaluation of the sensor signal.

Cross-Reference Information for Diagnostic Codes

Table 1 is a list of the diagnostic codes for this engine. The diagnostic codes are cross-referenced with the appropriate procedure that can be used to troubleshoot the code.

Active Diagnostic Trouble Codes

An active diagnostic trouble code indicated that a problem with the electronic control system exists at this time. Correct the problem as soon as possible.

When the ECM generates an active diagnostic trouble code, the amber warning lamp is illuminated in order to alert the operator. If the condition that generated the code is momentary, the warning lamp is turned off and the diagnostic trouble code becomes logged.

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 code

This 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.

• 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.

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.

Event Codes

Engine Monitoring

The Electronic Control Module (ECM) monitors the operating parameters of the engine. The ECM will generate an event code if a specific engine parameter exceeds an acceptable range that is defined by the engine monitoring system.

Cross-Reference Information for Event Codes

Parts of the Event Code

Event Code - The E identifies the code as an event code. The XXX(X) is a numeric identifier for the event code. The fourth "(X)" assigns one of three levels to the active event code according to the severity of the abnormal system condition. The code is followed by a description of the code. Refer to the following example:

• E360(1) Low Oil Pressure

• E360(2) Low Oil Pressure

• E360(3) Low Oil Pressure

The definition for the levels of severity for an event are defined below:

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 code

Logged 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 troubleshooting the engine, perform the following steps in order to diagnose a malfunction:

1. Obtain the following information about the complaint:

   • The event and the time of the event

   • Determine the conditions for the event. The conditions will include the engine rpm and the load.

   • Determine if there are any systems that were installed by the dealer or by the customer that could cause the event.

   • Determine whether any additional events occurred.

2. Verify that the complaint is not due to normal engine operation. Verify that the complaint is not due to error of the operator.

3. Narrow the probable cause. Consider the operator information, the conditions of operation, and the history of the engine.

4. Perform a visual inspection. Inspect the following items:

   • Fuel supply

   • Oil level

   • Oil supply

   • Wiring

   • Connectors

Be sure to check the connectors. This check is important for problems that are intermittent. Refer to Troubleshooting, "Electrical Connectors - Inspect".

If these steps do not resolve the problem, refer to Table 2 for the procedure to troubleshoot the event code.

Parameter Settings of the Engine Monitoring System

The default settings for the parameters are programmed at the factory. The parameter settings for the engine monitoring system can also be viewed on Caterpillar Electronic Technician (ET).

Parameters for the Monitoring System