I have a 1996 Ford Explorer, 2WD, 5.0L engine with an automatic transmission. It has 192,000 miles. The check engine light is on and the fault code is 401. I have replaced the EGR valve, vacuum diaphragm, vacuum solenoid and the EGR position sensor. I measured vacuum at the outlet of the EGR solenoid at 15 inches. The voltage at the solenoid is 12 volts. I used a vacuum pump to manually operate the EGR valve and the motor speed dropped, indicating that the EGR valve is working properly. After doing all this, clearing the code and driving for 10 miles, the check engine light comes back on with the same fault code. What can I do to correct the problem?
May 28, 2007 at 12:23 PM