I went to the mechanic who changed the ERG valve in and reset the code. He said its a generic code and he couldn't do anything else. I went to the toyota dealer who said they would have to change the vavle again since that's the code!!! the smog shop couldn't help they don't give detailed info on 2000 and above vehicles. So I need to pass smog and no one can help. it could be anything with the PO 401 code. I need to find out what it is and fix it. it's a 2000 Toyota Camry 4 cylinder.
7 Answers
P0401 TOYOTA - Exhaust Gas Recirculation Flow Insufficient Detected...Possible causes; EGR passage clogged, Faulty EGR Vacuum Modulator Valve, Faulty EGR Valve, Faulty EGR solenoid valve, EGR solenoid valve harness is open or shorted, EGR solenoid valve circuit poor electrical connection, Dead (Weak) battery, Faulty EGR temperature sensor and circuit, Exhaust gas leaks.....EGR flow malfunction could be caused by a clogged EGR valve or EGR tube. Before replacing any parts try cleaning the EGR valve, tube and passages.
I believe the VSV for that EGR valve ...most common cause for this code...is located under the Intake Manifold. You would need to get under the vehicle to Check and service it. However...if the Mechanic who replaced the EGR Valve it self....did not do a through cleaning of the EGR vacuum passageway in the intake manifold....you will have a restricted EGR Flow.....thus...the above code. Also...that EGR Tube mentioned above must be clear. One must assume it is clear of debris and carbon if the valve is new. My guess....the vsv is bad...or....the Tech who replaced the EGR Valve forgot to check and clean the passage in the intake manifold.
The Mechanic who changed the EGR valve told me that Toyotas don't have a manifold, How can I clean it?
Well....let's see ....if I google 2000 toyota Camry 4 cylinder engine...intake manifold...let's see what comes up.
Suggest you open the hood and look around the Engine compartment. Do you see something that looks like this?
I have a 2000 Toyota Camry and I had the PO401 code. It ended up being the vacuum modulator switch. I replaced the EGR valve and the vacuum modulator valve too but the code was coming from the switch.