DDEC V SYSTEM Low oil pressure Once the malfunction has been corrected, the DDEC system will return the engine to normal operation. Auxiliary shutdown It is important to point out that whenever the AWL or the RSL come on, the DDEC computer will determine where the problem is and will then store this information in its memory. The DDR can distinguish between codes now active and those stored in the ECU memory (inactive). The temperature of air in the intake system is increased with the addition of an EGR. DDEC is programmed to reduce fueling (power) for a short time to reduce air and coolant temperatures when necessary.
DDEC will store an information code that this event occurred, but no corrective action is required as this action is designed to maintain operation without a noticeable affect on vehicle performance. If the malfunction is intermittent, the lights will come on and go off as the computer senses the changing engine condition. Diagnostic Data Reader The Diagnostic Data Reader (DDR) is a special diagnostic tool that can be plugged into the engine computer memory to extract information related to the cause of the problem. See Figure 7. The malfunction code recorded in the computer memory will remain until it is erased by a technician. The malfunction code can also be obtained by the operator.
A Diagnostic Test Mode Switch is provided which, when pressed, will cause the AWL to flash a code number. It will, for example, flash twice. . . pause . . . flash once. . . pause. In other words, a code 21. Code 21 indicates the throttle position sensor input voltage is high. See Figure 8. Figure 7 Diagnostic Data Reader J 38500 NOTE: A code 25 (two flashes followed by 5 flashes) indicates all systems are working satisfactorily. 28 All information subject to change without notice. DDC-SVC-MAN-0039 Copyright © 2009 DETROIT DIESEL CORPORATION