Hi, I have a question regarding code 33. EGR valve opening not detected. My question is: Is this due to a faulty EGR SENSOR or the actual EGR VALVE? If neither, what else would cause this? I also have a code 41 indicating ssytem lean or no o2 sensor switching. I assume that's just as simple as replacing the 02 sensor? Thanks for all the help!

 

A code 33 is your EGR. Another code is set for the EGR solenoid?...the little electrical connection. A code 41 is indeed an O2 sensor. Replacing both should cost you less than $100, unless you have a V8 with 2 O2 sensors, and doesn't take that much time or labor. A Chilton, Haynes manual, or previous posts on EGR, will tell you how to manually test your EGR valve. After you repair/replace, unplug your battery cables for about 15-30 minutes to reset/clear these codes out of truck's computer memory. Then drive till you drop.