C175 Tier 4 Final Engines for Off-Highway Trucks Caterpillar

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. For information on the engine monitoring system, refer to Troubleshooting, "Engine Monitoring System".

Cross-Reference Information for Event Codes

Event codes are generated when abnormal operating conditions exist. Table 1 is a list of the event codes for the engine. The event codes are cross-referenced with the appropriate procedure that can be used to troubleshoot 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 1 is an example of the operating range of a sensor.

Illustration 1	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 troubleshoot the engine, perform the following steps 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" for additional information.

If these steps do not resolve the problem, refer to Table 1 for the procedure to troubleshoot the event code.