This is the error code my Autonostics OBD II CHECK ENGINE SCANNER & ERROR CODE READER gave me for my 97 Ford Ranger. See Fixing Your Check Engine Light on the Cheap for details.
Here are a few useful pages I found online describing a bit more about what that code means. I was hoping maybe it was something I could fix myself but it sounds kind of tricky so I’ll wait on that.
P0401 OBD-II Trouble Code
Insufficient EGR Flow
What does that mean?
EGR stands for Exhaust Gas Recirculation. It is part of the vehicle emmissions system, and is used to reduce combustion temperature and pressure to control Oxides of Nitrogen. There are generally three parts to the EGR system: the EGR valve, an actuator solenoid, and a differential pressure sensor (DPF). These things work together to deliver the correct amount of recirculation based on engine temperature, load, etc. The P0401 code means that OBD detected an insufficient amount of EGR.
Also this page has some potentially useful info for Fixing this on a Toyota.
[tags]P0401, OBD-II, OBD-II Trouble Code, 0401, 401, Ford Ranger, Ranger, Ford[/tags]