How do you check egr on 1999 Ford Explorer?
Why does the check engine light keep reoccuring with the same code PO401 EGR valve after the EGR valve was replaced This is on a Ford Explorer Sport Trac?
This issue is typically caused by a broken or jammed EGR (Exhaust Gas Recirculation Valve). To remedy the problem, you must remove the old EGR valve and replace it. Attached is an Article from AutoZone on how to determine if it is the EGR valve and how to replace the EGR on a Generation 3 (1996-1999) Ford Taurus, It will also determine if your problem lays in other EGR components.
What can you check or replace if the check engine light comes back on and the code is P401 and you have already replaced the EGR valve?
Check the EGR selenoid valve. The vacuum will pass throught the defective selenoid valve and go the EGR valve even if it has not been activated. The ECM will not detect a defective selenoid valve - only an EGR problem. DPFE sensor If it's a Ford product, you may need a DPFE sensor. You should also check for a restriction in the EGR passageway.
Not all Explorer engines had an EGR valve. If you have a 4.0, and it has an EGR, look on the driver's side of the engine, mounted to the upper intake manifold. It will be an aluminum colored metal or black plastic sensor, with one electrical connector and two hoses going to it. If you have a 5.0, it will be at the rear of the engine, mounted on the back of the throttle body.
P0401 is "EGR Flow Insufficient Detected". The possible causes are a bad DPF EGR sensor, a bad EGRVR solenoid or possibly a bad PCM. The first thing to check is the wiring for breaks and be sure the connectors are clean and tight. Also check the vacuum lines for proper routing and that there are no breaks or cracks in them. The emission system is warranted for 5 years/50,000 miles so if you are within…
This may sound crazy, but check the actual accelerator pedal assembly itself. My 2000 Explorer had an EGR system leak at the exhaust manifold which directed incredible heat onto the firewall. This resulted in melting the PLASTIC accelerator arm which is attached to a pivot point on the firewall adjacent from the leak. The arm melted and the pedal eventually rested on the floor, restricting it's stroke. I was pretty surprised, but it happened.