| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a failure diagnosing device for an exhaust gas recirculation device, preventing wrong diagnosis of an exhaust gas recirculation system by accurately detecting intake pipe pressure with simple control. <P>SOLUTION: Wrong diagnosis of the EGR system 31 is prevented by simple processing without individually and specifically performing judgement at the occurrence of various abnormalities other than the EGR system 31 and by canceling the failure diagnosing of the EGR system 31 with a judgement that intake pipe pressures P1off, Pon, P2off are not detected properly, when at least one of a first OFF time intake pipe pressure P1off and a second OFF time intake pipe pressure P2off is greater than a cancel judging value K. In this case, each intake pipe pressure improperly detected is accurately eliminated by setting especially the cancel judging value K based on an intake pipe pressure P when EGR OFF control is performed in a state with an EGR valve 33 stuck at a fully opened position. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
