, Salem, MA

January 25, 2014

Auto Scanner: New parts, but check engine light still comes on

Auto Scanner
Larry Rubenstein

---- — Q: I have a check engine light that comes on after 50 miles or so, and the fault code is 44; that is the code for a bad oxygen sensor, and I have changed them both. But after 50 miles, 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 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: I have an ’07 Ford Explorer, 4.6-liter, eight-cylinder, six-speed automatic, 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, and once while approaching a light at 10 mph. No codes are showing. The dealer has no clue. I’m fearful of a serious accident. Would greatly appreciate your trusted advice.

A: Sorry, I have to agree with the dealer on this one. There are no factory service bulletins concerning this problem. There is not a check engine light leaving the technician with a path to follow. The problem has only happened once a week on average. One of the rules in my business is, “In order to fix the problem, we have to be able to duplicate the problem.” I do apologize, as I know this is not what you wanted to hear, but it’s the way it is.

Q: I Have a ’96 Buick Regal with 100,000 miles, which is due for multiple maintenances. What were you referring to in last week’s column as “BG transmission flush?”

A: Flushing the fluids in a car is very important if you hope to keep the vehicle going for a few hundred thousand miles. A BG transmission flush is very simply put: a flush of the transmission fluid using the BG flushing system. You can find a shop near you by going to

Car Care Tip: When leaving your car at a service facility for repairs, make sure you give them a phone number to call you for authorization of repairs. If you change locations and won’t be at that phone, let the service facility know.


Larry Rubenstein is a master technician who owns a North Shore service station. His column appears every Saturday. Write to Larry at The Salem News, c/o Auto Scanner, 32 Dunham Road, Beverly, MA 01915, or send an email to