I have a F 150 98 truck 4.2 L and I it has the P 1406 code I alreday changed the egr valve, egr selenoid and the DPFE sensor and code still here I already checked all vacuum hoses and are ok the only doubt that i have is that the minimum voltaje in the DPFE sensor must be between .4 and .7 volts but I have 1 volt can be this my problem any suggestions