THE TROUBLE LIGHT KEEPS COMING ON WITH A PO 401 ...
2004 Acura RL
December, 2, 2010 AT 12:48 AM
The trouble light keeps coming on with a PO 401 code (insufficient fuel flow & exhaust valve recirculator). Every time I clear the trouble light it comes back on in a short time. I've put on a new EGR valve, O2 sensor and have put fuel injector cleaner in the gas tank. Now I'm being told to "try and replace the fuel injectors" (+/- $2000). The car runs perfectly, the light just keeps coming on. I plan on keeping the car but don't want to guess at replacing the fuel injectors and spend that kind of money. What will happen if I keep running it just the way it is? Every mechanic has given me a different story and the repairs so far haven't changed anything.
Is the engine pinging/detonating? If not you'll be okay a problem with the EGR system will increase Nox-oxides of nitrogen due to high combustion chamber temperature over 2500F deg
A code P0401 most likely means one or more of the following has happened
There is a blockage in the EGR (tube), most likely carbon buildup
The EGR valve is faulty
The EGR valve may not be opening due to a lack of vaccuum
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, There should be a noticeable 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)
December, 2, 2010 AT 1:05 AM
P0401 IS AN EGR FLOW
Exhaust Gas Recirculation (EGR) Valve Position Sensor Located On top right rear of engine