Q: I have a check-engine light that comes on after 50 miles or so and the fault code is 44 — that is bad oxygen sensor. I have changed both sensors, but the check engine light comes on with the same fault code. I have had the dealer look at this problem and no one can find a solution. I hope you can help.
A: I believe that you changed two oxygen sensors and it didn’t resolve the problem. I can’t, however, believe a competent repair shop with access to a good diagnostic chart cannot resolve the problem. Let’s start at the beginning. Code 44 is not a trouble code that says you should change the oxygen sensors. Code 44 means the following: There is a problem in the oxygen sensor circuit on the right side cylinder head. The oxygen sensor receives 12 volts for the heater from the fuel pump relay; this wire may be chafed, or the relay may not be functioning properly. Also, the ground circuit for the oxygen sensor needs to be checked with a digital voltage ohm meter. By any chance do you still have your receipt for the parts you bought to use as diagnostic tools? If so, you may want to return them and reinstall your old sensors. If the sensor has more than 60,000 miles on it, you may have just done some good maintenance by updating the sensors. Make sure the shop you are working with has a good understanding of what a Code 44 actually is.
Q: have an 2007 Ford Explorer, 4.6 V8, 6-speed automatic, with 41,000 miles. Over the past three weeks the car has stalled three times — once while taking a left turn, once while stopped at a light, once while approaching a light at 10 mph. No codes are showing, the dealer has no clue, and I’m fearful of a serious accident. Would greatly appreciate your trusted advice.