You are here:

Toyota Repair/Code PO401


1997 Toyota Land Cruiser.  Has 110000 miles on Engine.  Bought LC with Check Engine light on.  Had vacuum hoses checked and then cleared.  Two days later it was back on.  Back into shop they replaced Modulator
three days later CEL is back on.  Back to shop three weeks ago they replaced VSV and kept the vehicle for another week and drove it on local roads and Interstate to Spokane, WA.  I drove it another 300 miles and CEL stayed off.  This past Sunday drove to town and CEL is back and yes it is PO401 still.  What should a next test be?
Thank you for your help.

Have the shop check to see if this is a california certified vehicle, if so it will have a EGR gas remp sensor located on the bottom of the EGR valve casting, these sensors can fail at times. If that's not the problem maybe replacing the EGR valve would help.

Toyota Repair

All Answers

Answers by Expert:

Ask Experts


Ted Ritter


I have more than 28 years experience as toyota technician, I will be able to answer most questions related to the Toyota product line up to the present year models,I am located in the US but welcome questions from other regions of the world. When asking a question please provide specific information: year,model, engine,transmission information. Provide as much information as possible including a brief repair history if possible. I have been a volunteer here for more ten years an have answered over 16,000 questions helping Toyota owners with their problems and save thousands of dollars without any compensation, some of my answers are published on many other websites including google and various automotive forums. DONATIONS ARE VERY MUCH APPRECIATED, IF YOU HAVE RECIEVED HELPFUL INFORMATION PLEASE MAKE A DONATION. AS OF TODAY (JULY 22, 2014) ALL REQUESTED GRAPHICS, ILLUSTRATIONS, DIAGRAMS, PHOTOS, WILL REQUIRE THE MINUMUM DONATION UP FRONT.


Toyota technician since 1979,expert in electrical systems,OBD systems,engine repair, driveability problems,EFI systems,ASE certified,Toyota master technician.
Certified Hybrid Vehicle technician.

Toyota master technician, ASE certified in eight catagories, Hybrid vehicle certified. Toyota technical training: Engine Automatic transmission Manual transmission Drivetrain Electrical systems Brakes and chassis Air conditioning Engine performance and diagnostics Hybrid systems

©2017 All rights reserved.