QuestionYes I have also replaced the modulator valve.-------------------------
Followup To
Question -
Hello, I have a 1994 Toyota pickup with the v-6, I keep getting the code of 71 (EGR sys), I have replaced my EGR valve, mass air flow sensor, all my vaccum lines, taken off the upper intake manifold and cleaned it out. And I am still getting the same code. The only thing that I can think of left to do is try and replace the ECU. I would like to know if there is anything that I might have missed before I replace the ECU? Thank you for your time.
Answer -
Have you replaced the egr vacuum modulator valve, it's attached to the egr valve on a bracket, try replacing it, if it has been replaced already and the problem persists let me know.
AnswerI would hold off on replacing the ecu since it is the least likely cause, try replacing the egr control vacuum switching valve(VSV) first, also make sure that you use a vacuum hose diagram to make sure the hoses are attached correctly, finally remove the throttle body and make sure that the egr port is open and not clogged up with carbon but it sounds like you may have done that already.
Have you used a vacuum pump to apply vacuum directly the egr valve, does the engine stall when doing so?
