A more common failure is when
the EGR passages plug up causing the insufficient flow.
Then this confirms that
the EGR passages inside the plenum ARE NOT clogged.
- clogged or restricted
EGR passages - faulty EGR valve - EGR valve stuck closed - problems with the DPFE sensor (Ford)- problems with hoses to the DPFE sensor (Ford)- problem with the EGR vacuum switching valve (Toyota)- clogged catalytic converter - carboned up EGR temperature sensor - vacuum supply issues at the vacuum - operated EGR valve - electrical problems with the EGR valve control circuit - engine computer problems