code comes up for egr valve i took it off it moves with vac and i get a change in ohms when vac is applyed how can i test this and what are ohms readings should be
egr valve on 1997 Mazda Millenia
i'd like to know which EGR code came up. There are several but the first two areP0400: "Computer detects too much or too little change in intake pressure during EGR test," and P0404: "EGR valve position sensor circuit malfunction", that is that the EGR position sensor does not reach the targeted position when EGR control solenoid is commanded. First, check for 5.0 volts, key on, at LtGrn-Red wire. If OK, Key off, check for 2.7k Ohms resistance across sensor pins corresponding to LtGrn-Red & Blk-Yel wires. Check for about 500 Ohms resisitance across sensor pins corresponding to Blk-Yel & Red-Blk wires. Check for 2.7k Ohms @ 6"Hg vacuum. Check for 2.4k Ohms resistance across LtGrn-Red & Red-Blk wires, check for 100 Ohms @ 6"Hg vacuum. Sensor connected and key on, check for 0.8 volts at 0"Hg and about 4.8 volts at 6"vacuum. You may have to remove the EGR and check that the EGR passages in the manifold are not clogged with carbon, that's a possibility. I'd check if there's not something wrong with the EGR valve and electronics. Hope that helps.