Highway Robbery?

I own a car only because it's a necessity. Julie and I own one car that is 9 years old and has over 209,000 miles of use. We bought it used and are attempting to make it last as long as possible.

The check engine light came on so I took it to a garage. It cost $80 to read the "computer" and more to install a new gas filter. I was told that was the most likely cause. Two days later the light came back on. After talking with the mechanics I decided not to spend another $100-plus on the next "most likely cause." Also, I was told something about another issue that I knew to be untrue. I decided not to use the garage in the future and began doing my own routine maintenance work.


Oxygen Sensor. (Larger version)

I took the car to another garage. They charged $75 to read the trouble codes and told me four oxygen sensors and both catalytic converters were bad. Total estimated cost for repairs: $1,500. Things didn't ring true and solid to me. I asked the cost of replacing only the four oxygen sensors and was given an estimate of $750.

I said "No, thanks". After some research I bought an OBD-II reader. When I read the diagnostic codes I found the left front oxygen sensor was bad and that the engine has only three sensors. Also, I found the sensors on the web for $34 each and located them in town for about $53. The math worked out this way: assume 4 sensors at $60 each for a total of $240. Subtract $240 from the $750 estimate and the labor would have come to $510. The time required to replace four sensors is about one hour. $510 per hour?

I decided to test removing the one defective sensor before purchasing a new one. After breaking it loose with a wrench I tightened it back and moved to the electric connector to see what would be involved in reaching into the tight area to disconnect it. That's when I noticed a wire was severed on the sensor.


Severed Wire. (Larger version)

I removed the sensor, soldered the wire, reinstalled it, and cleared the trouble code from the computer. I've read the diagnostics repeatedly in the last week and the sensor is working.

OK, I saved $1,500 less the cost of the OBD-II reader but here's my frustration. Given the sensor's location it seems the severed wire wasn't accidental. It wasn't due to abrasion nor a mouse nor some road debris striking it. It appears the wire had been cut deliberately.

On the bright side, I've had to do some reading, research and learning to diagnose and isolate the correct sensor and understand how the emission system works. I quit keeping up with automotive technology about the time Ralph Nader wrote "Unsafe At Any Speed". This has been a good learning experience.