Detroit Diesel Electronic Control System Operation Whenever the AWL (Check Engine) or the RSL comes on, the DDEC 10 system will determine where the problem is and will then store this information in its memory. If the malfunction is intermittent, the lights will come on and go off as the computer senses the changing engine condition. 34 All information subject to change without notice. Copyright © 2017 DETROIT DIESEL CORPORATION DDC-SVC-MAN-0192