966H, 972H and 980H Wheel Loaders Power Train Electronic Control System Caterpillar

Illustration 1	g01873681
Temperature conditions for a typical temperature sensor that will determine when an ECM will activate a temperature event code and when the ECM will activate a diagnostic code for the sensor circuit

Event codes are activated by an ECM when a machine system condition is detected that is outside of the expected normal system range. The detected condition is within the operational range of the sensor that is being used to monitor the system.

When the ECM detects a sensor signal that is out of the sensor operational range, a diagnostic code will be activated. Generally, a diagnostic code and an event code will not be activated at the same time for the system and the sensor. However, if an Event Code is activated and a diagnostic code is activated for the involved sensor at the same time, always investigate and resolve the cause of the diagnostic code before troubleshooting the active Event. Resolving the cause of the diagnostic code could also cause the Event to clear.

In most instances, the circuit or the sensor will not be the cause of the active Event as the signal is still within the sensor operational range. The most likely cause of the active Event will be machine conditions that result in an abnormal system condition. For a subsystem that is monitored by a temperature sensor, an active high temperature Event could be caused by a number of conditions such as low coolant levels, dirty filters, clogged intakes, or cooling fan problems. When an Event is activated and a diagnostic code is not active for the involved sensor, always investigate the machine conditions that could be causing the problem before suspecting the sensor as the cause of the problem.

When a control module activates an event code, the operator or the technician will be alerted by an error message on the display. The message and / or an audible alarm will indicate the severity of the problem. All of the active events will be logged by the ECM. The active events and the logged events can be viewed on the Monitoring System Display or Caterpillar Electronic Technician (Cat ET).

Warning Levels

The ECM will assign one of three warnings levels to an active event code according to the severity of the abnormal system condition. Each warning level requires a specific response from the operator. The warning levels and required operator response are listed below.

Warning Level 1

An active warning level 1 event alerts the operator that a machine system could require attention. Level 1 events are logged, not displayed. If a Level 1 event is repeatedly activated, investigate the possible cause of the problem at the first opportunity. Check the involved system condition or perform maintenance on the involved system.

Warning Level 2

An active warning level 2 event can require a change in the operation of the machine to correct a problem. A warning level 2 event can indicate the need for a maintenance procedure. A level 2 warning that remains active or is repeatedly activated should be investigated at the earliest opportunity. Failure to correct the problem may result in the problem becoming more severe or possible damage to machine system components.

Warning Level 3

An active warning level 3 event requires an "Immediate Safe Engine Shutdown" by the operator to avoid possible damage to a machine system. Generally, a warning level 3 event will cause the ECM to disable operation of the involved system. The cause of the active event must be reset or resolved before the system can resume normal operation.

Indications and System Response

Monitoring System Display

Event codes are activated in one of three warning levels according to the severity of the condition.

Level 1 Events are logged only.

The Monitoring System Display will alert the operator when a level 2 or a level 3 Event is active.

The subsystem warning indicators on the display will illuminate when a EID is activated for some subsystems. When level 1 events are active, the subsystem warning indicator will be the only type of indicator that will illuminate.

The action Indicator will flash red when a level 2 warning or level 3 warning is active.

The action alarm is driven as an output directly from the Instrument Cluster. If a level 3 warning is active, the action alarm will sound a pulsing tone. The action alarm will sound these tones to alert the machine operator that immediate action is required.

If two warnings of a different level are active at the same time, the highest level warning will be displayed.

The Monitoring System Display response to these warning levels is shown in the following table.

Electronic Technician Service Tool

When an abnormal system operating condition occurs, the status screen on Cat ET will indicate that there is an active event.

Event codes are displayed on Cat ET in the following format:

EXXXX Description of the code

The "E" indicates that the code is an event code. The "XXXX" is a numeric identifier. The numeric identifier is followed by a description of the code.

Active event codes are listed in ascending numerical order. The code with the lowest number is listed first. The active event code is removed from the list when the condition is no longer present.

Logged Event Codes

All of the Events that are activated by the Transmission ECM are logged. Level 1 events are logged only. The Monitoring System Display will not give any indication that a level 1 event is active. When level 2 events or Level 3 events are active, the events will be logged and an event active message will be displayed on the Monitoring System Display.

Logged event codes are listed in chronological order. The most recent code is listed first.

A logged code is cleared from memory when one of the following conditions occur:

• The service technician manually clears the code.

• The code does not reoccur for 1000 hours.

• A new code is logged and there are already ten logged codes in memory. In this case, the oldest logged code is cleared.

Troubleshooting

General Troubleshooting Guidelines

Perform the following steps to troubleshoot an event:

1. Obtain the following information from the operator:
   • The event and the time of the event

   • Determine the machine operating conditions at the time of the event. Conditions such as engine rpm, machine load, or operating environment may be important.

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

2. Verify that the event is not due to normal machine operation. Verify that the event is not due to an error in the operation of the machine.

3. Attempt to reset the active Event to determine if the cause was due to a momentary condition.

4. Check all fluid levels and all oil levels.

5. Generally, an active event and an active diagnostic code for a related circuit will not be active at the same time. However, always check for active diagnostic codes that are related to the active event condition. Troubleshoot and repair the cause of any diagnostic codes that are active when an event is activated.

6. Locate the EID code for the active event that is listed in the following table and follow the recommended actions. The recommended actions that are suggested in the table are presented as a guide to machine system conditions that could cause the event to be activated. The specific cause of a particular event cannot always be predicted. Use the recommended actions as a guide and investigate any other conditions or circumstances that may indicate the cause of a specific active event.

Note: If a level 3 steering system event is activated, the event will be latched. Once the condition that has caused the event is resolved, the event must be reset by an ON / OFF / ON key start switch cycle.

Transmission ECM Event Codes

The following table lists the event codes that can be activated for machine systems that are controlled by the Transmission ECM. The recommended action is listed as a guide to machine system conditions that could cause the event to be activated. The actual cause of a specific active event may not be limited to the suggested actions that are listed.

Use the Monitoring System Display or Cat ET to determine the event codes that are active or logged.