Diagnostic Codes
Refer to Electronic Troubleshooting for an explanation of each diagnostic code.
Active Diagnostic Codes
The C-10 and the C-12 diagnostic codes are used by the electronic control system in order to warn the vehicle operator of a problem. The diagnostic codes also indicate the nature of the problem to the service technician. Some codes are only used to record an event and the codes do not indicate problems that need repair.
An active diagnostic code represents a problem. The problem should be investigated and the problem should be corrected as soon as possible. Repairing the cause of an active code will cause the code to be cleared.
When an active code is generated, the diagnostic lamp will turn on. The diagnostic lamp will remain on. The diagnostic lamp will flash after 5 seconds. If the condition that generates the fault only occurs for a brief moment, the diagnostic lamp will go off after five seconds. The code will also be logged.
Some codes only record an event. These events are not a performance problem. In these cases, troubleshooting is not required.
Some of the C-10 and C-12 diagnostic codes generate major changes in the engine operation or limits. The major changes occur as a result of the code that was generated.
Logged Diagnostic Codes and Events
When the ECM generates a diagnostic code, the ECM usually logs the code in permanent memory within the ECM. The ECM has an internal diagnostic clock. The ECM records the hour when a code is logged. Knowing the time and the frequency of the code can be a valuable tool to a technician that is troubleshooting intermittent problems. The logged codes can be retrieved with an electronic service tool. The logged codes can be erased with an electronic service tool. The logged codes can be a valuable tool when a technician is troubleshooting intermittent problems.
Note: Diagnostic Codes that are logged repeatedly may indicate a problem that needs special investigation. Some codes that are only logged only a few times. If the drivers do not complain about the codes, the codes may not need attention until a scheduled maintenance interval.
Refer to Electronic Troubleshooting, "Troubleshooting Diagnostic Codes" in order to troubleshoot a logged diagnostic code. If symptoms continue, refer to Electronic Troubleshooting, "Troubleshooting Without a Diagnostic Code".
Note: The most likely cause of an intermittent problem is a faulty connection or damaged wiring. The next likely cause is a component failure (sensor or switch for example). The least likely cause is the ECM.
Electronic Service Tools
The Caterpillar service tools for the C-10 and C-12 electronic control systems are designed to help the service technician do the following tasks:
- The technician can diagnose the faults and the system problems.
- The technician can calibrate the sensors.
- The technician can program the parameters.
- The technician can read the trip data.
- The technician can read status of the sensors and the switches.
The C-10 and the C-12 truck engines require an Electronic Control Analyzer Programmer (ECAP). The engines can also accept the CAT Electronic Technician (ET) in order to communicate with the C-10 and C-12 Electronic Control Module.
Accelerator Pedal Position Sensor
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| Illustration 1 | g00305968 |
Accelerator Pedal Position Sensor | |
The accelerator pedal position sensor is mounted to the back of the pedal. The pedal is supplied by the OEM. The accelerator pedal position sensor requires no adjustments. The accelerator pedal position sensor is automatically calibrated by the ECM. The correct calibration can be displayed with the electronic service tool. The percent throttle reading should be according to the following situations:
- When the throttle is completely released, the reading should be 3 percent of governor control movement.
- When the throttle is completely depressed, the reading should be 100 percent of governor control movement.