Usage:
Active Diagnostic Codes
Diagnostic codes are used by the 3176 system to warn the vehicle operator of a problem and indicate to the service technician the nature of the problem. Some codes are used only to record an event, and do not indicate problems.
An ACTIVE Diagnostic code represents a problem that should be investigated and corrected AS SOON AS POSSIBLE. Repairing the cause of an ACTIVE code will cause the code to be cleared from the ACTIVE Diagnostic Code screen.
When an ACTIVE code is generated, the 3176 Diagnostic Lamp will turn ON and remain ON, blinking every five seconds. If the condition generating the fault occurs only for a brief moment, the lamp will go OFF after five seconds and the fault will be LOGGED.
NOTE: After a problem has been investigated/corrected, the related diagnostic code should be cleared from memory.
ACTIVE codes may be viewed using either of the electronic service tools (ECAP or DDT), and may also be viewed using the diagnostic lamp and cruise control switches. The Diagnostic Lamp should not be confused with the Warning Lamp which is used with 3176 Caterpillar Engine Protection.
NOTE: Some troubleshooting procedures, such as disconnection of a sensor may cause diagnostic codes. Make sure all diagnostic codes are noted prior to the start of the troubleshooting procedure to avoid confusion.
Using The ECAP Or DDT To Display Active Codes
1. With key OFF, install an ECAP or DDT into the 3176 system.
2. Turn key ON (engine does not need to be started to view codes).
3. Refer to the Operating Manual and Special Instructions for the service tool (listed under 3176 Service Tools) to read the code(s). On the ECAP, the display menu will direct you to the proper screen to display diagnostic messages similar to the example below.
Using The Cruise Control Switches To Display Active Codes:
1. Turn key ON (engine does not need to be started to view codes).
2. The 3176 Diagnostic Lamp will turn ON for five seconds, blink OFF, turn ON again for five seconds, then OFF for five seconds. At the end of that time, the lamp will begin to flash the first number of the two-digit code (count the flashes). After two seconds OFF, then it will flash the second digit. If two or more codes are present, they will follow the first after a few seconds and be displayed in the same manner.
3. Active diagnostic codes may be displayed at any time by suing cruise control switches. With key ON or engine running, turn the cruise control ON/OFF switch to OFF, and move the SET/RESUME switch to RESUME position. Once the codes begin to flash the switch may be released. The 3176 Diagnostic Lamp will flash out all the codes that are currently ACTIVE, or intermittent codes that have occurred since the key was turned ON.
Example ECAP Screen: "Display ACTIVE Diagnostic Messages"
Logged Diagnostic Codes
When an ECM generates a diagnostic code, it usually logs the code in permanent memory within the ECM. The time the code occurred (in hours on the internal diagnostic clock) is logged along with the code. The logged codes can then be later retrieved or erased using an ECAP or DDT service tool. They can be a valuable indicator when troubleshooting intermittent problems.
When investigating Logged diagnostic codes, keep in mind:
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NOTE: Some troubleshooting procedures, such as disconnection of a sensor may cause diagnostic codes. Make sure all diagnostic codes are noted prior to the start of the troubleshooting procedure to avoid confusion.* Some codes may be sensitive, and may log occurrences that did not result in driver 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 connections or damaged wiring. Next likely is the component (sensor or injector, for instance). Least likely is the ECM.* Some codes represent "events", not failures. These codes are 71-00Idle Shutdown Override (01), 71-01 Idle Shutdown Occurrence (47), 84-00 Vehicle Overspeed Warning (41), and 190-00 Engine Overspeed Warning (35). The following Engine Protection Codes are events and faults: 100-01 Low Oil Pressure Warning (46), 100-11 Very Low Oil Pressure (46), 110-00 High Coolant Temperature Warning (61), 110-11 Very High Coolant Temperature (61), 111-01 Low Coolant Level Warning (62), 111-11 Very Low Coolant Level (62). Passwords are required to clear these faults from the log. An example of a "Logged Event" is below.* The ECM will automatically delete any logged diagnostic code after 100 ECM hours, except for those requiring Passwords to clear (see previous paragraph).
To troubleshoot a logged diagnostic code, refer to the procedure in this manual for troubleshooting the specific code first (Troubleshooting With A Diagnostic Code). If symptoms continue, use the procedure for troubleshooting symptoms (see Section 3: Troubleshooting Without A Diagnostic Code).
Using The ECAP Or DDT To Display Logged Codes:
With key ON or engine running, follow the directions of the Operating Manual and Special Instructions for ECAP or DDT (listed under 3176 Service Tools) to view the codes. The ECAP menu will direct you to the proper screen to display logged diagnostic messages.
Using The ECAP Or DDT To Clear Logged Codes:
Follow directions in the Operating Manual and Special Instructions for ECAP or DDT to clear logged codes. The ECAP menu will direct you to the proper screen to clear logged diagnostic codes, similar to the example below.
Example ECAP Screen: "Logged Faults"
Example ECAP Screen: "Logged Events"
