How fix the P0401 in mazda 1999 pick up - 2005 Mazda B3000 Cab

on a mazda protege. 1.8L. You have a clogged vacuum port. On that intake back by the EGR valve there should be a port with a vacuum hose that goes over to the Right side strut tower. That line should have vacuum. That controls your EGR boost solenoid. If that line does not have vacuum it will be clogged at the nipple where it comes out of the intake. Step two. Take off throttle body. Behind the throttle body, looking inside the intake, there should be a big vacuum port. It will be clogged. You will see a big black ring most likely around the hole where the port should be. I usually pull the EGR valve off the intake so it doesn't get carboned up. Blow through that vacuum port with shop air and use a pick and some carb cleaner on it. This should solve your issues with the egr flow issue on this vehicle. 9/10 the ports will be clogged. Good luck.

The basic code - P0401 relates to the EGR.EGR stands for Exhaust Gas Recirculation. This valve is located on the Manifold and can get 'clogged' and not allow the 'air' to escape.

Hi MIKE,maybe this PDFcan help you,Diagnostic Trouble Code Table ,good luck!

DTC's (trouble codes) are 4 digits long. I am taking it that you mean P0401.Here is a link to a page that explains the code and the possible fixes:

http://www.obd-codes.com/p0401

for p0401:
In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.
Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open.
Clean out the EGR valve and/or tubing to remove deposits.
Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model).
Replace the DPFE sensor (with a good quality / OEM one).
Replace the EGR valve.

The p0401 indicates a lack of egr flow. The DPFE sensor (ford basic part number 9J460) is the most common cause of this code. Call a ford dealer for a price and ask if your vehicle is covered under any emissions recall or program for p0401.

p0171-System Adaptive Fuel Too Lean

p0401-EGR

p0452-EVAP Fuel Tank Pressure Sensor Low Input

p0131-Upstream Heated 02 Sensor Circuit

Hope That Helps.

The dealer had an emissions recall for the car u own I suggest phoning the dealer and see if the update has been performed on your car.

p0401 means you have insufficient egr flow, what you will have to do is have the egr ports cleaned out. this will involve removal of the egr valve so it would be best to take it to your local dealer where they will be able to fix ya right up.

spark plugs. wires. or if no petrol pump og filter