got a question on an egr code.
i have the p0401 code i checked the voltage on my dpfe sensor and seemed good on that. i hooked all the lines back up to the sensor and started the engine, i then applied vacume to the egr valve and watched the voltage and i only got a .1v change. same thing while reving the engine. shouldn't the voltage go up when the vacume is applied. if this is so then should i replace the egr valve?