C9 Urban Transit Bus Engine Caterpillar

Many programmable parameters affect the engine operation. These parameters may be changed with the Caterpillar Electronic Technician (Cat ET). The parameters are stored in the ECM. The parameters are not stored in the personality module. Any parameter can be read. However, passwords protect parameters from unauthorized changes.

Two categories contain various parameters, System Configuration Parameters and Customer Specified Parameters. System Configuration Parameters can be altered with Cat ET only if the proper factory passwords are obtained.

Customer Specified Parameters can be changed with Cat ET only if the proper customer passwords are used. Refer to Troubleshooting, "Customer Passwords" and Troubleshooting, "Factory Passwords" for additional information.

Programming a New ECM

The Engine Control Module or the ECM is the brain of the system. So when a problem occurs, it is easy to assume that the ECM is responsible. This is usually the wrong assumption. Most failures occur at the wiring and connectors or at a sensor input or sensor output. Follow the procedures in the troubleshooting guide, and do not replace an ECM on an assumption. However, when your troubleshooting indicates that a failure has in fact occurred in the ECM, refer to Troubleshooting, "Replacing the ECM".

Note: If a replacement for the ECM is required, the Customer Parameters, the Injector Trim Codes, and the timing calibration can be transferred from the suspect ECM to the replacement ECM. Timing calibration will not be necessary. This feature requires Cat ET and this feature is only possible if the suspect ECM can communicate with Cat ET.