Almost any mechanical problem can be accurately diagnosed under ideal conditions; but, accurate diagnosis can become the norm under everyday conditions. Much of the long term success and acceptance of an engine is actually determined by the efficiency of thousands of shop foremen and technicians.
The purpose of engine diagnostic forms is to provide the customer with satisfaction and assist the technician in troubleshooting. Diagnostic forms provide a guide to finding problems quickly and easily, avoiding unnecessary repairs and expense. Engine diagnostic forms should not remain buried in a book in the service library. They should be taken right to the job and used in providing a systematic and time saving method of diagnosing engine problems.
Engine diagnostic forms begin with the basics progressing to the tests that are more difficult. This leads the technician in a path of diagnosis to check the more common problems first, then proceed to the less likely problems. The form should be followed in sequence, starting at test number one and continuing through to the final test. The order of the tests should be followed because some components depend on the function of other components for proper operation. Performing the tests out of order could cause an incorrect conclusion.
Two diagnostic forms are required to properly diagnose Series 40E diesel engines. The first form, Hard Start/No Start and Performance Engine Diagnostics, guides the technician through hard start or no start conditions in which the engine does not start or is difficult to start. The Performance Engine Diagnostics portion guides the technician through conditions in which the engine is running with some type of performance problem. An example would be a low power complaint. Illustrations when applicable are located on the reverse side of the form. They show the location of test points and how to hook up test equipment at each point.
The second form, Electronic Control System Diagnostics, lists all engine and vehicle related fault codes on the front side. A circuit index adjacent to each fault code is provided to assist the technician in quickly referring to the appropriate section of the manual for each fault code. Fault code descriptions, comments and probable causes are listed for each fault code on the list. This information will allow the technician to understand what the fault code is and the problem associated with it.
The reverse side of this form contains a schematic wiring diagram of the engine and chassis-mounted electronic controls. A chart is supplied that describes the ECM engine —mounted versus chassis-mounted expected signal values under specified conditions. The chart will enable the experienced technician to quickly identify and repair the problem.
|Series 40E Troubleshooting Manual – 6SE241|
|Generated on 10-13-2008|